Question: What is kubectl taint?

Answer: kubectl taintSynopsisUpdate the taints on one or more nodes.A taint consists of a key, value, and effect. As an argument here, it is expressed as key=value:effect.The key must begin with a letter or number, and may contain letters, numbers, hyphens, dots, and underscores, up to 253 characters.Optionally, the key can begin with a DNS subdomain prefix and a single '/', like example.com/my-app.The value is optional. If given, it must begin with a letter or number, and may contain letters, numbers, hyphens, dots, and underscores, up to 63 characters.The effect must be NoSchedule, PreferNoSchedule or NoExecute.Currently taint can only apply to node.kubectl taint NODE NAME KEY_1=VAL_1:TAINT_EFFECT_1 ... KEY_N=VAL_N:TAINT_EFFECT_N Examples # Update node 'foo' with a taint with key 'dedicated' and value 'special-user' and effect 'NoSchedule' # If a taint with that key and effect already exists, its value is replaced as specified kubectl taint nodes foo dedicated=special-user:NoSchedule # Remove from node 'foo' the taint with key 'dedicated' and effect 'NoSchedule' if one exists kubectl taint nodes foo dedicated:NoSchedule- # Remove from node 'foo' all the taints with key 'dedicated' kubectl taint nodes foo dedicated- # Add a taint with key 'dedicated' on nodes having label myLabel=X kubectl taint node -l myLabel=X dedicated=foo:PreferNoSchedule # Add to node 'foo' a taint with key 'bar' and no value kubectl taint nodes foo bar:NoSchedule Options--allSelect all nodes in the cluster--allow-missing-template-keys Default: trueIf true, ignore any errors in templates when a field or map key is missing in the template. Only applies to golang and jsonpath output formats.--dry-run string[="unchanged"] Default: "none"Must be "none", "server", or "client". If client strategy, only print the object that would be sent, without sending it. If server strategy, submit server-side request without persisting the resource.--field-manager string Default: "kubectl-taint"Name of the manager used to track field ownership.-h, --helphelp for taint-o, --output stringOutput format. One of: (json, yaml, name, go-template, go-template-file, template, templatefile, jsonpath, jsonpath-as-json, jsonpath-file).--overwriteIf true, allow taints to be overwritten, otherwise reject taint updates that overwrite existing taints.-l, --selector stringSelector (label query) to filter on, supports '=', '==', '!=', 'in', 'notin'.(e.g. -l key1=value1,key2=value2,key3 in (value3)). Matching objects must satisfy all of the specified label constraints.--show-managed-fieldsIf true, keep the managedFields when printing objects in JSON or YAML format.--template stringTemplate string or path to template file to use when -o=go-template, -o=go-template-file. The template format is golang templates [http://golang.org/pkg/text/template/#pkg-overview].--validate string[="strict"] Default: "strict"Must be one of: strict (or true), warn, ignore (or false). "true" or "strict" will use a schema to validate the inp


Question: How does kubectl taint work?

Answer: kubectl taintSynopsisUpdate the taints on one or more nodes.A taint consists of a key, value, and effect. As an argument here, it is expressed as key=value:effect.The key must begin with a letter or number, and may contain letters, numbers, hyphens, dots, and underscores, up to 253 characters.Optionally, the key can begin with a DNS subdomain prefix and a single '/', like example.com/my-app.The value is optional. If given, it must begin with a letter or number, and may contain letters, numbers, hyphens, dots, and underscores, up to 63 characters.The effect must be NoSchedule, PreferNoSchedule or NoExecute.Currently taint can only apply to node.kubectl taint NODE NAME KEY_1=VAL_1:TAINT_EFFECT_1 ... KEY_N=VAL_N:TAINT_EFFECT_N Examples # Update node 'foo' with a taint with key 'dedicated' and value 'special-user' and effect 'NoSchedule' # If a taint with that key and effect already exists, its value is replaced as specified kubectl taint nodes foo dedicated=special-user:NoSchedule # Remove from node 'foo' the taint with key 'dedicated' and effect 'NoSchedule' if one exists kubectl taint nodes foo dedicated:NoSchedule- # Remove from node 'foo' all the taints with key 'dedicated' kubectl taint nodes foo dedicated- # Add a taint with key 'dedicated' on nodes having label myLabel=X kubectl taint node -l myLabel=X dedicated=foo:PreferNoSchedule # Add to node 'foo' a taint with key 'bar' and no value kubectl taint nodes foo bar:NoSchedule Options--allSelect all nodes in the cluster--allow-missing-template-keys Default: trueIf true, ignore any errors in templates when a field or map key is missing in the template. Only applies to golang and jsonpath output formats.--dry-run string[="unchanged"] Default: "none"Must be "none", "server", or "client". If client strategy, only print the object that would be sent, without sending it. If server strategy, submit server-side request without persisting the resource.--field-manager string Default: "kubectl-taint"Name of the manager used to track field ownership.-h, --helphelp for taint-o, --output stringOutput format. One of: (json, yaml, name, go-template, go-template-file, template, templatefile, jsonpath, jsonpath-as-json, jsonpath-file).--overwriteIf true, allow taints to be overwritten, otherwise reject taint updates that overwrite existing taints.-l, --selector stringSelector (label query) to filter on, supports '=', '==', '!=', 'in', 'notin'.(e.g. -l key1=value1,key2=value2,key3 in (value3)). Matching objects must satisfy all of the specified label constraints.--show-managed-fieldsIf true, keep the managedFields when printing objects in JSON or YAML format.--template stringTemplate string or path to template file to use when -o=go-template, -o=go-template-file. The template format is golang templates [http://golang.org/pkg/text/template/#pkg-overview].--validate string[="strict"] Default: "strict"Must be one of: strict (or true), warn, ignore (or false). "true" or "strict" will use a schema to validate the inp


Question: When would you use kubectl taint?

Answer: kubectl taintSynopsisUpdate the taints on one or more nodes.A taint consists of a key, value, and effect. As an argument here, it is expressed as key=value:effect.The key must begin with a letter or number, and may contain letters, numbers, hyphens, dots, and underscores, up to 253 characters.Optionally, the key can begin with a DNS subdomain prefix and a single '/', like example.com/my-app.The value is optional. If given, it must begin with a letter or number, and may contain letters, numbers, hyphens, dots, and underscores, up to 63 characters.The effect must be NoSchedule, PreferNoSchedule or NoExecute.Currently taint can only apply to node.kubectl taint NODE NAME KEY_1=VAL_1:TAINT_EFFECT_1 ... KEY_N=VAL_N:TAINT_EFFECT_N Examples # Update node 'foo' with a taint with key 'dedicated' and value 'special-user' and effect 'NoSchedule' # If a taint with that key and effect already exists, its value is replaced as specified kubectl taint nodes foo dedicated=special-user:NoSchedule # Remove from node 'foo' the taint with key 'dedicated' and effect 'NoSchedule' if one exists kubectl taint nodes foo dedicated:NoSchedule- # Remove from node 'foo' all the taints with key 'dedicated' kubectl taint nodes foo dedicated- # Add a taint with key 'dedicated' on nodes having label myLabel=X kubectl taint node -l myLabel=X dedicated=foo:PreferNoSchedule # Add to node 'foo' a taint with key 'bar' and no value kubectl taint nodes foo bar:NoSchedule Options--allSelect all nodes in the cluster--allow-missing-template-keys Default: trueIf true, ignore any errors in templates when a field or map key is missing in the template. Only applies to golang and jsonpath output formats.--dry-run string[="unchanged"] Default: "none"Must be "none", "server", or "client". If client strategy, only print the object that would be sent, without sending it. If server strategy, submit server-side request without persisting the resource.--field-manager string Default: "kubectl-taint"Name of the manager used to track field ownership.-h, --helphelp for taint-o, --output stringOutput format. One of: (json, yaml, name, go-template, go-template-file, template, templatefile, jsonpath, jsonpath-as-json, jsonpath-file).--overwriteIf true, allow taints to be overwritten, otherwise reject taint updates that overwrite existing taints.-l, --selector stringSelector (label query) to filter on, supports '=', '==', '!=', 'in', 'notin'.(e.g. -l key1=value1,key2=value2,key3 in (value3)). Matching objects must satisfy all of the specified label constraints.--show-managed-fieldsIf true, keep the managedFields when printing objects in JSON or YAML format.--template stringTemplate string or path to template file to use when -o=go-template, -o=go-template-file. The template format is golang templates [http://golang.org/pkg/text/template/#pkg-overview].--validate string[="strict"] Default: "strict"Must be one of: strict (or true), warn, ignore (or false). "true" or "strict" will use a schema to validate the inp


Question: What are the benefits of kubectl taint?

Answer: kubectl taintSynopsisUpdate the taints on one or more nodes.A taint consists of a key, value, and effect. As an argument here, it is expressed as key=value:effect.The key must begin with a letter or number, and may contain letters, numbers, hyphens, dots, and underscores, up to 253 characters.Optionally, the key can begin with a DNS subdomain prefix and a single '/', like example.com/my-app.The value is optional. If given, it must begin with a letter or number, and may contain letters, numbers, hyphens, dots, and underscores, up to 63 characters.The effect must be NoSchedule, PreferNoSchedule or NoExecute.Currently taint can only apply to node.kubectl taint NODE NAME KEY_1=VAL_1:TAINT_EFFECT_1 ... KEY_N=VAL_N:TAINT_EFFECT_N Examples # Update node 'foo' with a taint with key 'dedicated' and value 'special-user' and effect 'NoSchedule' # If a taint with that key and effect already exists, its value is replaced as specified kubectl taint nodes foo dedicated=special-user:NoSchedule # Remove from node 'foo' the taint with key 'dedicated' and effect 'NoSchedule' if one exists kubectl taint nodes foo dedicated:NoSchedule- # Remove from node 'foo' all the taints with key 'dedicated' kubectl taint nodes foo dedicated- # Add a taint with key 'dedicated' on nodes having label myLabel=X kubectl taint node -l myLabel=X dedicated=foo:PreferNoSchedule # Add to node 'foo' a taint with key 'bar' and no value kubectl taint nodes foo bar:NoSchedule Options--allSelect all nodes in the cluster--allow-missing-template-keys Default: trueIf true, ignore any errors in templates when a field or map key is missing in the template. Only applies to golang and jsonpath output formats.--dry-run string[="unchanged"] Default: "none"Must be "none", "server", or "client". If client strategy, only print the object that would be sent, without sending it. If server strategy, submit server-side request without persisting the resource.--field-manager string Default: "kubectl-taint"Name of the manager used to track field ownership.-h, --helphelp for taint-o, --output stringOutput format. One of: (json, yaml, name, go-template, go-template-file, template, templatefile, jsonpath, jsonpath-as-json, jsonpath-file).--overwriteIf true, allow taints to be overwritten, otherwise reject taint updates that overwrite existing taints.-l, --selector stringSelector (label query) to filter on, supports '=', '==', '!=', 'in', 'notin'.(e.g. -l key1=value1,key2=value2,key3 in (value3)). Matching objects must satisfy all of the specified label constraints.--show-managed-fieldsIf true, keep the managedFields when printing objects in JSON or YAML format.--template stringTemplate string or path to template file to use when -o=go-template, -o=go-template-file. The template format is golang templates [http://golang.org/pkg/text/template/#pkg-overview].--validate string[="strict"] Default: "strict"Must be one of: strict (or true), warn, ignore (or false). "true" or "strict" will use a schema to validate the inp


Question: What is Synopsis?

Answer: U p d a t e   t h e   t a i n t s   o n   o n e   o r   m o r e   n o d e s .   A   t a i n t   c o n s i s t s   o f   a   k e y ,   v a l u e ,   a n d   e f f e c t .   A s   a n   a r g u m e n t   h e r e ,   i t   i s   e x p r e s s e d   a s   k e y = v a l u e : e f f e c t . T h e   k e y   m u s t   b e g i n   w i t h   a   l e t t e r   o r   n u m b e r ,   a n d   m a y   c o n t a i n   l e t t e r s ,   n u m b e r s ,   h y p h e n s ,   d o t s ,   a n d   u n d e r s c o r e s ,   u p   t o   2 5 3   c h a r a c t e r s . O p t i o n a l l y ,   t h e   k e y   c a n   b e g i n   w i t h   a   D N S   s u b d o m a i n   p r e f i x   a n d   a   s i n g l e   ' / ' ,   l i k e   e x a m p l e . c o m / m y - a p p . T h e   v a l u e   i s   o p t i o n a l .   I f   g i v e n ,   i t   m u s t   b e g i n   w i t h   a   l e t t e r   o r   n u m b e r ,   a n d   m a y   c o n t a i n   l e t t e r s ,   n u m b e r s ,   h y p h e n s ,   d o t s ,   a n d   u n d e r s c o r e s ,   u p   t o   6 3   c h a r a c t e r s . T h e   e f f e c t   m u s t   b e   N o S c h e d u l e ,   P r e f e r N o S c h e d u l e   o r   N o E x e c u t e . C u r r e n t l y   t a i n t   c a n   o n l y   a p p l y   t o   n o d e .   k u b e c t l   t a i n t   N O D E   N A M E   K E Y _ 1 = V A L _ 1 : T A I N T _ E F F E C T _ 1   . . .   K E Y _ N = V A L _ N : T A I N T _ E F F E C T _ N


Question: What is Examples?

Answer: #   U p d a t e   n o d e   ' f o o '   w i t h   a   t a i n t   w i t h   k e y   ' d e d i c a t e d '   a n d   v a l u e   ' s p e c i a l - u s e r '   a n d   e f f e c t   ' N o S c h e d u l e '   #   I f   a   t a i n t   w i t h   t h a t   k e y   a n d   e f f e c t   a l r e a d y   e x i s t s ,   i t s   v a l u e   i s   r e p l a c e d   a s   s p e c i f i e d   k u b e c t l   t a i n t   n o d e s   f o o   d e d i c a t e d = s p e c i a l - u s e r : N o S c h e d u l e   #   R e m o v e   f r o m   n o d e   ' f o o '   t h e   t a i n t   w i t h   k e y   ' d e d i c a t e d '   a n d   e f f e c t   ' N o S c h e d u l e '   i f   o n e   e x i s t s   k u b e c t l   t a i n t   n o d e s   f o o   d e d i c a t e d : N o S c h e d u l e -   #   R e m o v e   f r o m   n o d e   ' f o o '   a l l   t h e   t a i n t s   w i t h   k e y   ' d e d i c a t e d '   k u b e c t l   t a i n t   n o d e s   f o o   d e d i c a t e d -   #   A d d   a   t a i n t   w i t h   k e y   ' d e d i c a t e d '   o n   n o d e s   h a v i n g   l a b e l   m y L a b e l = X   k u b e c t l   t a i n t   n o d e   - l   m y L a b e l = X   d e d i c a t e d = f o o : P r e f e r N o S c h e d u l e   #   A d d   t o   n o d e   ' f o o '   a   t a i n t   w i t h   k e y   ' b a r '   a n d   n o   v a l u e   k u b e c t l   t a i n t   n o d e s   f o o   b a r : N o S c h e d u l e


Question: What is Options?

Answer: S e l e c t   a l l   n o d e s   i n   t h e   c l u s t e r   I f   t r u e ,   i g n o r e   a n y   e r r o r s   i n   t e m p l a t e s   w h e n   a   f i e l d   o r   m a p   k e y   i s   m i s s i n g   i n   t h e   t e m p l a t e .   O n l y   a p p l i e s   t o   g o l a n g   a n d   j s o n p a t h   o u t p u t   f o r m a t s .   M u s t   b e   " n o n e " ,   " s e r v e r " ,   o r   " c l i e n t " .   I f   c l i e n t   s t r a t e g y ,   o n l y   p r i n t   t h e   o b j e c t   t h a t   w o u l d   b e   s e n t ,   w i t h o u t   s e n d i n g   i t .   I f   s e r v e r   s t r a t e g y ,   s u b m i t   s e r v e r - s i d e   r e q u e s t   w i t h o u t   p e r s i s t i n g   t h e   r e s o u r c e .   N a m e   o f   t h e   m a n a g e r   u s e d   t o   t r a c k   f i e l d   o w n e r s h i p .   h e l p   f o r   t a i n t   O u t p u t   f o r m a t .   O n e   o f :   ( j s o n ,   y a m l ,   n a m e ,   g o - t e m p l a t e ,   g o - t e m p l a t e - f i l e ,   t e m p l a t e ,   t e m p l a t e f i l e ,   j s o n p a t h ,   j s o n p a t h - a s - j s o n ,   j s o n p a t h - f i l e ) .   I f   t r u e ,   a l l o w   t a i n t s   t o   b e   o v e r w r i t t e n ,   o t h e r w i s e   r e j e c t   t a i n t   u p d a t e s   t h a t   o v e r w r i t e   e x i s t i n g   t a i n t s .   S e l e c t o r   ( l a b e l   q u e r y )   t o   f i l t e r   o n ,   s u p p o r t s   ' = ' ,   ' = = ' ,   ' ! = ' ,   ' i n ' ,   ' n o t i n ' . ( e . g .   - l   k e y 1 = v a l u e 1 , k e y 2 = v a l u e 2 , k e y 3   i n   ( v a l u e 3 ) ) .   M a t c h i n g   o b j e c t s   m u s t   s a t i s f y   a l l   o f   t h e   s p e c i f i e d   l a b e l   c o n s t r a i n t s .   I f   t r u e ,   k e e p   t h e   m a n a g e d F i e l d s   w h e n   p r i n t i n g   o b j e c t s   i n   J S O N   o r   Y A M L   f o r m a t .   T e m p l a t e   s t r i n g   o r   p a t h   t o   t e m p l a t e


Question: What is Parent Options Inherited?

Answer: U s e r n a m e   t o   i m p e r s o n a t e   f o r   t h e   o p e r a t i o n .   U s e r   c o u l d   b e   a   r e g u l a r   u s e r   o r   a   s e r v i c e   a c c o u n t   i n   a   n a m e s p a c e .   G r o u p   t o   i m p e r s o n a t e   f o r   t h e   o p e r a t i o n ,   t h i s   f l a g   c a n   b e   r e p e a t e d   t o   s p e c i f y   m u l t i p l e   g r o u p s .   U I D   t o   i m p e r s o n a t e   f o r   t h e   o p e r a t i o n .   D e f a u l t   c a c h e   d i r e c t o r y   P a t h   t o   a   c e r t   f i l e   f o r   t h e   c e r t i f i c a t e   a u t h o r i t y   P a t h   t o   a   c l i e n t   c e r t i f i c a t e   f i l e   f o r   T L S   P a t h   t o   a   c l i e n t   k e y   f i l e   f o r   T L S   T h e   n a m e   o f   t h e   k u b e c o n f i g   c l u s t e r   t o   u s e   T h e   n a m e   o f   t h e   k u b e c o n f i g   c o n t e x t   t o   u s e   I f   t r u e ,   o p t - o u t   o f   r e s p o n s e   c o m p r e s s i o n   f o r   a l l   r e q u e s t s   t o   t h e   s e r v e r   I f   t r u e ,   t h e   s e r v e r ' s   c e r t i f i c a t e   w i l l   n o t   b e   c h e c k e d   f o r   v a l i d i t y .   T h i s   w i l l   m a k e   y o u r   H T T P S   c o n n e c t i o n s   i n s e c u r e   P a t h   t o   t h e   k u b e c o n f i g   f i l e   t o   u s e   f o r   C L I   r e q u e s t s .   P a t h   t o   t h e   k u b e r c   f i l e   t o   u s e   f o r   p r e f e r e n c e s .   T h i s   c a n   b e   d i s a b l e d   b y   e x p o r t i n g   K U B E C T L _ K U B E R C = f a l s e   f e a t u r e   g a t e   o r   t u r n i n g   o f f   t h e   f e a t u r e   K U B E R C = o f f .   R e q u i r e   s e r v e r   v e r s i o n   t o   m a t c h   c l i e n t   v e r s i o n   I f   p r e s e n t ,   t h e   n a m e s p a c e   s c o p e   f o r   t h i s   C L I   r e q u e s t   P a s s w o r d   f o r   b a s i c   a u t h e n t i c a t


Question: What is See Also?

Answer: k u b e c t l   -   k u b e c t l   c o n t r o l s   t h e   K u b e r n e t e s   c l u s t e r   m a n a g e r   T h i s   p a g e   i s   a u t o m a t i c a l l y   g e n e r a t e d .   I f   y o u   p l a n   t o   r e p o r t   a n   i s s u e   w i t h   t h i s   p a g e ,   m e n t i o n   t h a t   t h e   p a g e   i s   a u t o - g e n e r a t e d   i n   y o u r   i s s u e   d e s c r i p t i o n .   T h e   f i x   m a y   n e e d   t o   h a p p e n   e l s e w h e r e   i n   t h e   K u b e r n e t e s   p r o j e c t .


Question: What is Logging Architecture?

Answer: Logging ArchitectureApplication logs can help you understand what is happening inside your application. The logs are particularly useful for debugging problems and monitoring cluster activity. Most modern applications have some kind of logging mechanism. Likewise, container engines are designed to support logging. The easiest and most adopted logging method for containerized applications is writing to standard output and standard error streams.However, the native functionality provided by a container engine or runtime is usually not enough for a complete logging solution.For example, you may want to access your application's logs if a container crashes, a pod gets evicted, or a node dies.In a cluster, logs should have a separate storage and lifecycle independent of nodes, pods, or containers. This concept is called cluster-level logging.Cluster-level logging architectures require a separate backend to store, analyze, and query logs. Kubernetes does not provide a native storage solution for log data. Instead, there are many logging solutions that integrate with Kubernetes. The following sections describe how to handle and store logs on nodes.Pod and container logsKubernetes captures logs from each container in a running Pod.This example uses a manifest for a Pod with a container that writes text to the standard output stream, once per second.debug/counter-pod.yaml apiVersion: v1 kind: Pod metadata: name: counter spec: containers: - name: count image: busybox:1.28 args: [/bin/sh, -c, 'i=0; while true; do echo "$i: $(date)"; i=$((i+1)); sleep 1; done'] To run this pod, use the following command:kubectl apply -f https://k8s.io/examples/debug/counter-pod.yaml The output is:pod/counter created To fetch the logs, use the kubectl logs command, as follows:kubectl logs counter The output is similar to:0: Fri Apr 1 11:42:23 UTC 2022 1: Fri Apr 1 11:42:24 UTC 2022 2: Fri Apr 1 11:42:25 UTC 2022 You can use kubectl logs --previous to retrieve logs from a previous instantiation of a container. If your pod has multiple containers, specify which container's logs you want to access by appending a container name to the command, with a -c flag, like so:kubectl logs counter -c count Container log streamsFEATURE STATE: Kubernetes v1.32 [alpha] (enabled by default: false)As an alpha feature, the kubelet can split out the logs from the two standard streams produced by a container: standard output and standard error. To use this behavior, you must enable the PodLogsQuerySplitStreams feature gate. With that feature gate enabled, Kubernetes 1.34 allows access to these log streams directly via the Pod API. You can fetch a specific stream by specifying the stream name (either Stdout or Stderr), using the stream query string. You must have access to read the log subresource of that Pod.To demonstrate this feature, you can create a Pod that periodically writes text to both the standard output and error stream.debug/counter-pod-err.yaml apiVersion: v1 kind: Pod metadata: name:


Question: How does Logging Architecture work?

Answer: Logging ArchitectureApplication logs can help you understand what is happening inside your application. The logs are particularly useful for debugging problems and monitoring cluster activity. Most modern applications have some kind of logging mechanism. Likewise, container engines are designed to support logging. The easiest and most adopted logging method for containerized applications is writing to standard output and standard error streams.However, the native functionality provided by a container engine or runtime is usually not enough for a complete logging solution.For example, you may want to access your application's logs if a container crashes, a pod gets evicted, or a node dies.In a cluster, logs should have a separate storage and lifecycle independent of nodes, pods, or containers. This concept is called cluster-level logging.Cluster-level logging architectures require a separate backend to store, analyze, and query logs. Kubernetes does not provide a native storage solution for log data. Instead, there are many logging solutions that integrate with Kubernetes. The following sections describe how to handle and store logs on nodes.Pod and container logsKubernetes captures logs from each container in a running Pod.This example uses a manifest for a Pod with a container that writes text to the standard output stream, once per second.debug/counter-pod.yaml apiVersion: v1 kind: Pod metadata: name: counter spec: containers: - name: count image: busybox:1.28 args: [/bin/sh, -c, 'i=0; while true; do echo "$i: $(date)"; i=$((i+1)); sleep 1; done'] To run this pod, use the following command:kubectl apply -f https://k8s.io/examples/debug/counter-pod.yaml The output is:pod/counter created To fetch the logs, use the kubectl logs command, as follows:kubectl logs counter The output is similar to:0: Fri Apr 1 11:42:23 UTC 2022 1: Fri Apr 1 11:42:24 UTC 2022 2: Fri Apr 1 11:42:25 UTC 2022 You can use kubectl logs --previous to retrieve logs from a previous instantiation of a container. If your pod has multiple containers, specify which container's logs you want to access by appending a container name to the command, with a -c flag, like so:kubectl logs counter -c count Container log streamsFEATURE STATE: Kubernetes v1.32 [alpha] (enabled by default: false)As an alpha feature, the kubelet can split out the logs from the two standard streams produced by a container: standard output and standard error. To use this behavior, you must enable the PodLogsQuerySplitStreams feature gate. With that feature gate enabled, Kubernetes 1.34 allows access to these log streams directly via the Pod API. You can fetch a specific stream by specifying the stream name (either Stdout or Stderr), using the stream query string. You must have access to read the log subresource of that Pod.To demonstrate this feature, you can create a Pod that periodically writes text to both the standard output and error stream.debug/counter-pod-err.yaml apiVersion: v1 kind: Pod metadata: name:


Question: When would you use Logging Architecture?

Answer: Logging ArchitectureApplication logs can help you understand what is happening inside your application. The logs are particularly useful for debugging problems and monitoring cluster activity. Most modern applications have some kind of logging mechanism. Likewise, container engines are designed to support logging. The easiest and most adopted logging method for containerized applications is writing to standard output and standard error streams.However, the native functionality provided by a container engine or runtime is usually not enough for a complete logging solution.For example, you may want to access your application's logs if a container crashes, a pod gets evicted, or a node dies.In a cluster, logs should have a separate storage and lifecycle independent of nodes, pods, or containers. This concept is called cluster-level logging.Cluster-level logging architectures require a separate backend to store, analyze, and query logs. Kubernetes does not provide a native storage solution for log data. Instead, there are many logging solutions that integrate with Kubernetes. The following sections describe how to handle and store logs on nodes.Pod and container logsKubernetes captures logs from each container in a running Pod.This example uses a manifest for a Pod with a container that writes text to the standard output stream, once per second.debug/counter-pod.yaml apiVersion: v1 kind: Pod metadata: name: counter spec: containers: - name: count image: busybox:1.28 args: [/bin/sh, -c, 'i=0; while true; do echo "$i: $(date)"; i=$((i+1)); sleep 1; done'] To run this pod, use the following command:kubectl apply -f https://k8s.io/examples/debug/counter-pod.yaml The output is:pod/counter created To fetch the logs, use the kubectl logs command, as follows:kubectl logs counter The output is similar to:0: Fri Apr 1 11:42:23 UTC 2022 1: Fri Apr 1 11:42:24 UTC 2022 2: Fri Apr 1 11:42:25 UTC 2022 You can use kubectl logs --previous to retrieve logs from a previous instantiation of a container. If your pod has multiple containers, specify which container's logs you want to access by appending a container name to the command, with a -c flag, like so:kubectl logs counter -c count Container log streamsFEATURE STATE: Kubernetes v1.32 [alpha] (enabled by default: false)As an alpha feature, the kubelet can split out the logs from the two standard streams produced by a container: standard output and standard error. To use this behavior, you must enable the PodLogsQuerySplitStreams feature gate. With that feature gate enabled, Kubernetes 1.34 allows access to these log streams directly via the Pod API. You can fetch a specific stream by specifying the stream name (either Stdout or Stderr), using the stream query string. You must have access to read the log subresource of that Pod.To demonstrate this feature, you can create a Pod that periodically writes text to both the standard output and error stream.debug/counter-pod-err.yaml apiVersion: v1 kind: Pod metadata: name:


Question: What are the benefits of Logging Architecture?

Answer: Logging ArchitectureApplication logs can help you understand what is happening inside your application. The logs are particularly useful for debugging problems and monitoring cluster activity. Most modern applications have some kind of logging mechanism. Likewise, container engines are designed to support logging. The easiest and most adopted logging method for containerized applications is writing to standard output and standard error streams.However, the native functionality provided by a container engine or runtime is usually not enough for a complete logging solution.For example, you may want to access your application's logs if a container crashes, a pod gets evicted, or a node dies.In a cluster, logs should have a separate storage and lifecycle independent of nodes, pods, or containers. This concept is called cluster-level logging.Cluster-level logging architectures require a separate backend to store, analyze, and query logs. Kubernetes does not provide a native storage solution for log data. Instead, there are many logging solutions that integrate with Kubernetes. The following sections describe how to handle and store logs on nodes.Pod and container logsKubernetes captures logs from each container in a running Pod.This example uses a manifest for a Pod with a container that writes text to the standard output stream, once per second.debug/counter-pod.yaml apiVersion: v1 kind: Pod metadata: name: counter spec: containers: - name: count image: busybox:1.28 args: [/bin/sh, -c, 'i=0; while true; do echo "$i: $(date)"; i=$((i+1)); sleep 1; done'] To run this pod, use the following command:kubectl apply -f https://k8s.io/examples/debug/counter-pod.yaml The output is:pod/counter created To fetch the logs, use the kubectl logs command, as follows:kubectl logs counter The output is similar to:0: Fri Apr 1 11:42:23 UTC 2022 1: Fri Apr 1 11:42:24 UTC 2022 2: Fri Apr 1 11:42:25 UTC 2022 You can use kubectl logs --previous to retrieve logs from a previous instantiation of a container. If your pod has multiple containers, specify which container's logs you want to access by appending a container name to the command, with a -c flag, like so:kubectl logs counter -c count Container log streamsFEATURE STATE: Kubernetes v1.32 [alpha] (enabled by default: false)As an alpha feature, the kubelet can split out the logs from the two standard streams produced by a container: standard output and standard error. To use this behavior, you must enable the PodLogsQuerySplitStreams feature gate. With that feature gate enabled, Kubernetes 1.34 allows access to these log streams directly via the Pod API. You can fetch a specific stream by specifying the stream name (either Stdout or Stderr), using the stream query string. You must have access to read the log subresource of that Pod.To demonstrate this feature, you can create a Pod that periodically writes text to both the standard output and error stream.debug/counter-pod-err.yaml apiVersion: v1 kind: Pod metadata: name:


Question: What is Logging Architecture?

Answer: A p p l i c a t i o n   l o g s   c a n   h e l p   y o u   u n d e r s t a n d   w h a t   i s   h a p p e n i n g   i n s i d e   y o u r   a p p l i c a t i o n .   T h e   l o g s   a r e   p a r t i c u l a r l y   u s e f u l   f o r   d e b u g g i n g   p r o b l e m s   a n d   m o n i t o r i n g   c l u s t e r   a c t i v i t y .   M o s t   m o d e r n   a p p l i c a t i o n s   h a v e   s o m e   k i n d   o f   l o g g i n g   m e c h a n i s m .   L i k e w i s e ,   c o n t a i n e r   e n g i n e s   a r e   d e s i g n e d   t o   s u p p o r t   l o g g i n g .   T h e   e a s i e s t   a n d   m o s t   a d o p t e d   l o g g i n g   m e t h o d   f o r   c o n t a i n e r i z e d   a p p l i c a t i o n s   i s   w r i t i n g   t o   s t a n d a r d   o u t p u t   a n d   s t a n d a r d   e r r o r   s t r e a m s .   H o w e v e r ,   t h e   n a t i v e   f u n c t i o n a l i t y   p r o v i d e d   b y   a   c o n t a i n e r   e n g i n e   o r   r u n t i m e   i s   u s u a l l y   n o t   e n o u g h   f o r   a   c o m p l e t e   l o g g i n g   s o l u t i o n .   F o r   e x a m p l e ,   y o u   m a y   w a n t   t o   a c c e s s   y o u r   a p p l i c a t i o n ' s   l o g s   i f   a   c o n t a i n e r   c r a s h e s ,   a   p o d   g e t s   e v i c t e d ,   o r   a   n o d e   d i e s .   I n   a   c l u s t e r ,   l o g s   s h o u l d   h a v e   a   s e p a r a t e   s t o r a g e   a n d   l i f e c y c l e   i n d e p e n d e n t   o f   n o d e s ,   p o d s ,   o r   c o n t a i n e r s .   T h i s   c o n c e p t   i s   c a l l e d   c l u s t e r - l e v e l   l o g g i n g .   C l u s t e r - l e v e l   l o g g i n g   a r c h i t e c t u r e s   r e q u i r e   a   s e p a r a t e   b a c k e n d   t o   s t o r e ,   a n a l y z e ,   a n d   q u e r y   l o g s .   K u b e r n e t e s   d o e s   n o t   p r o v i d e   a   n a t i v e   s t o r a g e   s o l u t i o n   f o r   l o g   d a t a .   I


Question: What is Pod and container logs?

Answer: K u b e r n e t e s   c a p t u r e s   l o g s   f r o m   e a c h   c o n t a i n e r   i n   a   r u n n i n g   P o d .   T h i s   e x a m p l e   u s e s   a   m a n i f e s t   f o r   a   P o d   w i t h   a   c o n t a i n e r   t h a t   w r i t e s   t e x t   t o   t h e   s t a n d a r d   o u t p u t   s t r e a m ,   o n c e   p e r   s e c o n d .   a p i V e r s i o n :   v 1   k i n d :   P o d   m e t a d a t a :   n a m e :   c o u n t e r   s p e c :   c o n t a i n e r s :   -   n a m e :   c o u n t   i m a g e :   b u s y b o x : 1 . 2 8   a r g s :   [ / b i n / s h ,   - c ,   ' i = 0 ;   w h i l e   t r u e ;   d o   e c h o   " $ i :   $ ( d a t e ) " ;   i = $ ( ( i + 1 ) ) ;   s l e e p   1 ;   d o n e ' ]   T o   r u n   t h i s   p o d ,   u s e   t h e   f o l l o w i n g   c o m m a n d :   k u b e c t l   a p p l y   - f   h t t p s : / / k 8 s . i o / e x a m p l e s / d e b u g / c o u n t e r - p o d . y a m l   T h e   o u t p u t   i s :   p o d / c o u n t e r   c r e a t e d   T o   f e t c h   t h e   l o g s ,   u s e   t h e   k u b e c t l   l o g s   c o m m a n d ,   a s   f o l l o w s :   k u b e c t l   l o g s   c o u n t e r   T h e   o u t p u t   i s   s i m i l a r   t o :   0 :   F r i   A p r   1   1 1 : 4 2 : 2 3   U T C   2 0 2 2   1 :   F r i   A p r   1   1 1 : 4 2 : 2 4   U T C   2 0 2 2   2 :   F r i   A p r   1   1 1 : 4 2 : 2 5   U T C   2 0 2 2   Y o u   c a n   u s e   k u b e c t l   l o g s   - - p r e v i o u s   t o   r e t r i e v e   l o g s   f r o m   a   p r e v i o u s   i n s t a n t i a t i o n   o f   a   c o n t a i n e r .   I f   y o u r   p o d   h a s   m u l t i p l e   c o n t a i n e r s ,   s p e c i f y   w h i c h   c o n t a i n e r ' s   l o g s   y o u   w a n t   t o   a c c e s s   b y   a p p e n d i n g   a   c o n t a i n e r   n a m e   t o   t h e   c o m m a n d ,   w i t h   a   - c   f l a g ,   l i k e   s o :   k u b e c t l   l o g s   c o u n t e r   - c   c


Question: What is Container log streams?

Answer: A s   a n   a l p h a   f e a t u r e ,   t h e   k u b e l e t   c a n   s p l i t   o u t   t h e   l o g s   f r o m   t h e   t w o   s t a n d a r d   s t r e a m s   p r o d u c e d   b y   a   c o n t a i n e r :   s t a n d a r d   o u t p u t   a n d   s t a n d a r d   e r r o r .   T o   u s e   t h i s   b e h a v i o r ,   y o u   m u s t   e n a b l e   t h e   P o d L o g s Q u e r y S p l i t S t r e a m s   f e a t u r e   g a t e .   W i t h   t h a t   f e a t u r e   g a t e   e n a b l e d ,   K u b e r n e t e s   1 . 3 4   a l l o w s   a c c e s s   t o   t h e s e   l o g   s t r e a m s   d i r e c t l y   v i a   t h e   P o d   A P I .   Y o u   c a n   f e t c h   a   s p e c i f i c   s t r e a m   b y   s p e c i f y i n g   t h e   s t r e a m   n a m e   ( e i t h e r   S t d o u t   o r   S t d e r r ) ,   u s i n g   t h e   s t r e a m   q u e r y   s t r i n g .   Y o u   m u s t   h a v e   a c c e s s   t o   r e a d   t h e   l o g   s u b r e s o u r c e   o f   t h a t   P o d .   T o   d e m o n s t r a t e   t h i s   f e a t u r e ,   y o u   c a n   c r e a t e   a   P o d   t h a t   p e r i o d i c a l l y   w r i t e s   t e x t   t o   b o t h   t h e   s t a n d a r d   o u t p u t   a n d   e r r o r   s t r e a m .   a p i V e r s i o n :   v 1   k i n d :   P o d   m e t a d a t a :   n a m e :   c o u n t e r - e r r   s p e c :   c o n t a i n e r s :   -   n a m e :   c o u n t   i m a g e :   b u s y b o x : 1 . 2 8   a r g s :   [ / b i n / s h ,   - c ,   ' i = 0 ;   w h i l e   t r u e ;   d o   e c h o   " $ i :   $ ( d a t e ) " ;   e c h o   " $ i :   e r r "   > & 2   ;   i = $ ( ( i + 1 ) ) ;   s l e e p   1 ;   d o n e ' ]   T o   r u n   t h i s   p o d ,   u s e   t h e   f o l l o w i n g   c o m m a n d :   k u b e c t l   a p p l y   - f   h t t p s : / / k 8 s . i o / e x a m p l e s / d e b u g / c o u n t e r - p o d - e r r . y a m l   T o   f e t c h   o n l y   t h e   s t d e r r   l o g


Question: What is How nodes handle container logs?

Answer: A   c o n t a i n e r   r u n t i m e   h a n d l e s   a n d   r e d i r e c t s   a n y   o u t p u t   g e n e r a t e d   t o   a   c o n t a i n e r i z e d   a p p l i c a t i o n ' s   s t d o u t   a n d   s t d e r r   s t r e a m s .   D i f f e r e n t   c o n t a i n e r   r u n t i m e s   i m p l e m e n t   t h i s   i n   d i f f e r e n t   w a y s ;   h o w e v e r ,   t h e   i n t e g r a t i o n   w i t h   t h e   k u b e l e t   i s   s t a n d a r d i z e d   a s   t h e   C R I   l o g g i n g   f o r m a t .   B y   d e f a u l t ,   i f   a   c o n t a i n e r   r e s t a r t s ,   t h e   k u b e l e t   k e e p s   o n e   t e r m i n a t e d   c o n t a i n e r   w i t h   i t s   l o g s .   I f   a   p o d   i s   e v i c t e d   f r o m   t h e   n o d e ,   a l l   c o r r e s p o n d i n g   c o n t a i n e r s   a r e   a l s o   e v i c t e d ,   a l o n g   w i t h   t h e i r   l o g s .   T h e   k u b e l e t   m a k e s   l o g s   a v a i l a b l e   t o   c l i e n t s   v i a   a   s p e c i a l   f e a t u r e   o f   t h e   K u b e r n e t e s   A P I .   T h e   u s u a l   w a y   t o   a c c e s s   t h i s   i s   b y   r u n n i n g   k u b e c t l   l o g s .


Question: What is Log rotation?

Answer: T h e   k u b e l e t   i s   r e s p o n s i b l e   f o r   r o t a t i n g   c o n t a i n e r   l o g s   a n d   m a n a g i n g   t h e   l o g g i n g   d i r e c t o r y   s t r u c t u r e .   T h e   k u b e l e t   s e n d s   t h i s   i n f o r m a t i o n   t o   t h e   c o n t a i n e r   r u n t i m e   ( u s i n g   C R I ) ,   a n d   t h e   r u n t i m e   w r i t e s   t h e   c o n t a i n e r   l o g s   t o   t h e   g i v e n   l o c a t i o n .   Y o u   c a n   c o n f i g u r e   t w o   k u b e l e t   c o n f i g u r a t i o n   s e t t i n g s ,   c o n t a i n e r L o g M a x S i z e   ( d e f a u l t   1 0 M i )   a n d   c o n t a i n e r L o g M a x F i l e s   ( d e f a u l t   5 ) ,   u s i n g   t h e   k u b e l e t   c o n f i g u r a t i o n   f i l e .   T h e s e   s e t t i n g s   l e t   y o u   c o n f i g u r e   t h e   m a x i m u m   s i z e   f o r   e a c h   l o g   f i l e   a n d   t h e   m a x i m u m   n u m b e r   o f   f i l e s   a l l o w e d   f o r   e a c h   c o n t a i n e r   r e s p e c t i v e l y .   I n   o r d e r   t o   p e r f o r m   a n   e f f i c i e n t   l o g   r o t a t i o n   i n   c l u s t e r s   w h e r e   t h e   v o l u m e   o f   t h e   l o g s   g e n e r a t e d   b y   t h e   w o r k l o a d   i s   l a r g e ,   k u b e l e t   a l s o   p r o v i d e s   a   m e c h a n i s m   t o   t u n e   h o w   t h e   l o g s   a r e   r o t a t e d   i n   t e r m s   o f   h o w   m a n y   c o n c u r r e n t   l o g   r o t a t i o n s   c a n   b e   p e r f o r m e d   a n d   t h e   i n t e r v a l   a t   w h i c h   t h e   l o g s   a r e   m o n i t o r e d   a n d   r o t a t e d   a s   r e q u i r e d .   Y o u   c a n   c o n f i g u r e   t w o   k u b e l e t   c o n f i g u r a t i o n   s e t t i n g s ,   c o n t a i n e r L o g M a x W o r k e r s   a n d   c o n t a i n e r L o g M o n i t o r I n t e r v a l   u s i n g   t h e   k u b e l e t   c


Question: What is Note:?

Answer: O n l y   t h e   c o n t e n t s   o f   t h e   l a t e s t   l o g   f i l e   a r e   a v a i l a b l e   t h r o u g h   k u b e c t l   l o g s .   F o r   e x a m p l e ,   i f   a   P o d   w r i t e s   4 0   M i B   o f   l o g s   a n d   t h e   k u b e l e t   r o t a t e s   l o g s   a f t e r   1 0   M i B ,   r u n n i n g   k u b e c t l   l o g s   r e t u r n s   a t   m o s t   1 0 M i B   o f   d a t a .


Question: What is System component logs?

Answer: T h e r e   a r e   t w o   t y p e s   o f   s y s t e m   c o m p o n e n t s :   t h o s e   t h a t   t y p i c a l l y   r u n   i n   a   c o n t a i n e r ,   a n d   t h o s e   c o m p o n e n t s   d i r e c t l y   i n v o l v e d   i n   r u n n i n g   c o n t a i n e r s .   F o r   e x a m p l e :   T h e   k u b e l e t   a n d   c o n t a i n e r   r u n t i m e   d o   n o t   r u n   i n   c o n t a i n e r s .   T h e   k u b e l e t   r u n s   y o u r   c o n t a i n e r s   ( g r o u p e d   t o g e t h e r   i n   p o d s ) T h e   K u b e r n e t e s   s c h e d u l e r ,   c o n t r o l l e r   m a n a g e r ,   a n d   A P I   s e r v e r   r u n   w i t h i n   p o d s   ( u s u a l l y   s t a t i c   P o d s ) .   T h e   e t c d   c o m p o n e n t   r u n s   i n   t h e   c o n t r o l   p l a n e ,   a n d   m o s t   c o m m o n l y   a l s o   a s   a   s t a t i c   p o d .   I f   y o u r   c l u s t e r   u s e s   k u b e - p r o x y ,   y o u   t y p i c a l l y   r u n   t h i s   a s   a   D a e m o n S e t .


Question: What is Log locations?

Answer: T h e   w a y   t h a t   t h e   k u b e l e t   a n d   c o n t a i n e r   r u n t i m e   w r i t e   l o g s   d e p e n d s   o n   t h e   o p e r a t i n g   s y s t e m   t h a t   t h e   n o d e   u s e s :   O n   L i n u x   n o d e s   t h a t   u s e   s y s t e m d ,   t h e   k u b e l e t   a n d   c o n t a i n e r   r u n t i m e   w r i t e   t o   j o u r n a l d   b y   d e f a u l t .   Y o u   u s e   j o u r n a l c t l   t o   r e a d   t h e   s y s t e m d   j o u r n a l ;   f o r   e x a m p l e :   j o u r n a l c t l   - u   k u b e l e t . I f   s y s t e m d   i s   n o t   p r e s e n t ,   t h e   k u b e l e t   a n d   c o n t a i n e r   r u n t i m e   w r i t e   t o   . l o g   f i l e s   i n   t h e   / v a r / l o g   d i r e c t o r y .   I f   y o u   w a n t   t o   h a v e   l o g s   w r i t t e n   e l s e w h e r e ,   y o u   c a n   i n d i r e c t l y   r u n   t h e   k u b e l e t   v i a   a   h e l p e r   t o o l ,   k u b e - l o g - r u n n e r ,   a n d   u s e   t h a t   t o o l   t o   r e d i r e c t   k u b e l e t   l o g s   t o   a   d i r e c t o r y   t h a t   y o u   c h o o s e . B y   d e f a u l t ,   k u b e l e t   d i r e c t s   y o u r   c o n t a i n e r   r u n t i m e   t o   w r i t e   l o g s   i n t o   d i r e c t o r i e s   w i t h i n   / v a r / l o g / p o d s . F o r   m o r e   i n f o r m a t i o n   o n   k u b e - l o g - r u n n e r ,   r e a d   S y s t e m   L o g s .   O n   L i n u x   n o d e s   t h a t   u s e   s y s t e m d ,   t h e   k u b e l e t   a n d   c o n t a i n e r   r u n t i m e   w r i t e   t o   j o u r n a l d   b y   d e f a u l t .   Y o u   u s e   j o u r n a l c t l   t o   r e a d   t h e   s y s t e m d   j o u r n a l ;   f o r   e x a m p l e :   j o u r n a l c t l   - u   k u b e l e t .   I f   s y s t e m d   i s   n o t   p r e s e n t ,   t h e   k u b e l e t   a n d   c o n t a i n e r   r u n t i m e   w r i t e   t o


Question: What is Caution:?

Answer: I t ' s   i m p o r t a n t   t o   n o t e   t h a t   t h e   d e f a u l t   l o c a t i o n   / v a r / l o g / p o d s   h a s   b e e n   i n   u s e   f o r   a n   e x t e n d e d   p e r i o d   a n d   c e r t a i n   p r o c e s s e s   m i g h t   i m p l i c i t l y   a s s u m e   t h i s   p a t h .   T h e r e f o r e ,   a l t e r i n g   t h i s   p a r a m e t e r   m u s t   b e   a p p r o a c h e d   w i t h   c a u t i o n   a n d   a t   y o u r   o w n   r i s k .   A n o t h e r   c a v e a t   t o   k e e p   i n   m i n d   i s   t h a t   t h e   k u b e l e t   s u p p o r t s   t h e   l o c a t i o n   b e i n g   o n   t h e   s a m e   d i s k   a s   / v a r .   O t h e r w i s e ,   i f   t h e   l o g s   a r e   o n   a   s e p a r a t e   f i l e s y s t e m   f r o m   / v a r ,   t h e n   t h e   k u b e l e t   w i l l   n o t   t r a c k   t h a t   f i l e s y s t e m ' s   u s a g e ,   p o t e n t i a l l y   l e a d i n g   t o   i s s u e s   i f   i t   f i l l s   u p .   F o r   d e t a i l s   a b o u t   e t c d   a n d   i t s   l o g s ,   v i e w   t h e   e t c d   d o c u m e n t a t i o n .   A g a i n ,   y o u   c a n   u s e   K u b e r n e t e s '   s t o r a g e   m e c h a n i s m s   t o   m a p   p e r s i s t e n t   s t o r a g e   i n t o   t h e   c o n t a i n e r   t h a t   r u n s   t h e   c o m p o n e n t .


Question: What is Note:?

Answer: I f   y o u   d e p l o y   K u b e r n e t e s   c l u s t e r   c o m p o n e n t s   ( s u c h   a s   t h e   s c h e d u l e r )   t o   l o g   t o   a   v o l u m e   s h a r e d   f r o m   t h e   p a r e n t   n o d e ,   y o u   n e e d   t o   c o n s i d e r   a n d   e n s u r e   t h a t   t h o s e   l o g s   a r e   r o t a t e d .   K u b e r n e t e s   d o e s   n o t   m a n a g e   t h a t   l o g   r o t a t i o n .   Y o u r   o p e r a t i n g   s y s t e m   m a y   a u t o m a t i c a l l y   i m p l e m e n t   s o m e   l o g   r o t a t i o n   -   f o r   e x a m p l e ,   i f   y o u   s h a r e   t h e   d i r e c t o r y   / v a r / l o g   i n t o   a   s t a t i c   P o d   f o r   a   c o m p o n e n t ,   n o d e - l e v e l   l o g   r o t a t i o n   t r e a t s   a   f i l e   i n   t h a t   d i r e c t o r y   t h e   s a m e   a s   a   f i l e   w r i t t e n   b y   a n y   c o m p o n e n t   o u t s i d e   K u b e r n e t e s .   S o m e   d e p l o y   t o o l s   a c c o u n t   f o r   t h a t   l o g   r o t a t i o n   a n d   a u t o m a t e   i t ;   o t h e r s   l e a v e   t h i s   a s   y o u r   r e s p o n s i b i l i t y .


Question: What is Cluster-level logging architectures?

Answer: W h i l e   K u b e r n e t e s   d o e s   n o t   p r o v i d e   a   n a t i v e   s o l u t i o n   f o r   c l u s t e r - l e v e l   l o g g i n g ,   t h e r e   a r e   s e v e r a l   c o m m o n   a p p r o a c h e s   y o u   c a n   c o n s i d e r .   H e r e   a r e   s o m e   o p t i o n s :   U s e   a   n o d e - l e v e l   l o g g i n g   a g e n t   t h a t   r u n s   o n   e v e r y   n o d e . I n c l u d e   a   d e d i c a t e d   s i d e c a r   c o n t a i n e r   f o r   l o g g i n g   i n   a n   a p p l i c a t i o n   p o d . P u s h   l o g s   d i r e c t l y   t o   a   b a c k e n d   f r o m   w i t h i n   a n   a p p l i c a t i o n .


Question: What is Using a node logging agent?

Answer: Y o u   c a n   i m p l e m e n t   c l u s t e r - l e v e l   l o g g i n g   b y   i n c l u d i n g   a   n o d e - l e v e l   l o g g i n g   a g e n t   o n   e a c h   n o d e .   T h e   l o g g i n g   a g e n t   i s   a   d e d i c a t e d   t o o l   t h a t   e x p o s e s   l o g s   o r   p u s h e s   l o g s   t o   a   b a c k e n d .   C o m m o n l y ,   t h e   l o g g i n g   a g e n t   i s   a   c o n t a i n e r   t h a t   h a s   a c c e s s   t o   a   d i r e c t o r y   w i t h   l o g   f i l e s   f r o m   a l l   o f   t h e   a p p l i c a t i o n   c o n t a i n e r s   o n   t h a t   n o d e .   B e c a u s e   t h e   l o g g i n g   a g e n t   m u s t   r u n   o n   e v e r y   n o d e ,   i t   i s   r e c o m m e n d e d   t o   r u n   t h e   a g e n t   a s   a   D a e m o n S e t .   N o d e - l e v e l   l o g g i n g   c r e a t e s   o n l y   o n e   a g e n t   p e r   n o d e   a n d   d o e s n ' t   r e q u i r e   a n y   c h a n g e s   t o   t h e   a p p l i c a t i o n s   r u n n i n g   o n   t h e   n o d e .   C o n t a i n e r s   w r i t e   t o   s t d o u t   a n d   s t d e r r ,   b u t   w i t h   n o   a g r e e d   f o r m a t .   A   n o d e - l e v e l   a g e n t   c o l l e c t s   t h e s e   l o g s   a n d   f o r w a r d s   t h e m   f o r   a g g r e g a t i o n .


Question: What is Using a sidecar container with the logging agent?

Answer: Y o u   c a n   u s e   a   s i d e c a r   c o n t a i n e r   i n   o n e   o f   t h e   f o l l o w i n g   w a y s :   T h e   s i d e c a r   c o n t a i n e r   s t r e a m s   a p p l i c a t i o n   l o g s   t o   i t s   o w n   s t d o u t . T h e   s i d e c a r   c o n t a i n e r   r u n s   a   l o g g i n g   a g e n t ,   w h i c h   i s   c o n f i g u r e d   t o   p i c k   u p   l o g s   f r o m   a n   a p p l i c a t i o n   c o n t a i n e r .


Question: What is Streaming sidecar container?

Answer: B y   h a v i n g   y o u r   s i d e c a r   c o n t a i n e r s   w r i t e   t o   t h e i r   o w n   s t d o u t   a n d   s t d e r r   s t r e a m s ,   y o u   c a n   t a k e   a d v a n t a g e   o f   t h e   k u b e l e t   a n d   t h e   l o g g i n g   a g e n t   t h a t   a l r e a d y   r u n   o n   e a c h   n o d e .   T h e   s i d e c a r   c o n t a i n e r s   r e a d   l o g s   f r o m   a   f i l e ,   a   s o c k e t ,   o r   j o u r n a l d .   E a c h   s i d e c a r   c o n t a i n e r   p r i n t s   a   l o g   t o   i t s   o w n   s t d o u t   o r   s t d e r r   s t r e a m .   T h i s   a p p r o a c h   a l l o w s   y o u   t o   s e p a r a t e   s e v e r a l   l o g   s t r e a m s   f r o m   d i f f e r e n t   p a r t s   o f   y o u r   a p p l i c a t i o n ,   s o m e   o f   w h i c h   c a n   l a c k   s u p p o r t   f o r   w r i t i n g   t o   s t d o u t   o r   s t d e r r .   T h e   l o g i c   b e h i n d   r e d i r e c t i n g   l o g s   i s   m i n i m a l ,   s o   i t ' s   n o t   a   s i g n i f i c a n t   o v e r h e a d .   A d d i t i o n a l l y ,   b e c a u s e   s t d o u t   a n d   s t d e r r   a r e   h a n d l e d   b y   t h e   k u b e l e t ,   y o u   c a n   u s e   b u i l t - i n   t o o l s   l i k e   k u b e c t l   l o g s .   F o r   e x a m p l e ,   a   p o d   r u n s   a   s i n g l e   c o n t a i n e r ,   a n d   t h e   c o n t a i n e r   w r i t e s   t o   t w o   d i f f e r e n t   l o g   f i l e s   u s i n g   t w o   d i f f e r e n t   f o r m a t s .   H e r e ' s   a   m a n i f e s t   f o r   t h e   P o d :   a p i V e r s i o n :   v 1   k i n d :   P o d   m e t a d a t a :   n a m e :   c o u n t e r   s p e c :   c o n t a i n e r s :   -   n a m e :   c o u n t   i m a g e :   b u s y b o x : 1 . 2 8   a r g s :   -   / b i n / s h   -   - c   -   >   i = 0 ;   w h i l e   t r u e ;   d o   e c h o   " $ i :   $ ( d a t e ) "   > >   / v a r /


Question: What is Sidecar container with a logging agent?

Answer: I f   t h e   n o d e - l e v e l   l o g g i n g   a g e n t   i s   n o t   f l e x i b l e   e n o u g h   f o r   y o u r   s i t u a t i o n ,   y o u   c a n   c r e a t e   a   s i d e c a r   c o n t a i n e r   w i t h   a   s e p a r a t e   l o g g i n g   a g e n t   t h a t   y o u   h a v e   c o n f i g u r e d   s p e c i f i c a l l y   t o   r u n   w i t h   y o u r   a p p l i c a t i o n .


Question: What is Note:?

Answer: H e r e   a r e   t w o   e x a m p l e   m a n i f e s t s   t h a t   y o u   c a n   u s e   t o   i m p l e m e n t   a   s i d e c a r   c o n t a i n e r   w i t h   a   l o g g i n g   a g e n t .   T h e   f i r s t   m a n i f e s t   c o n t a i n s   a   C o n f i g M a p   t o   c o n f i g u r e   f l u e n t d .   a p i V e r s i o n :   v 1   k i n d :   C o n f i g M a p   m e t a d a t a :   n a m e :   f l u e n t d - c o n f i g   d a t a :   f l u e n t d . c o n f :   |   < s o u r c e >   t y p e   t a i l   f o r m a t   n o n e   p a t h   / v a r / l o g / 1 . l o g   p o s _ f i l e   / v a r / l o g / 1 . l o g . p o s   t a g   c o u n t . f o r m a t 1   < / s o u r c e >   < s o u r c e >   t y p e   t a i l   f o r m a t   n o n e   p a t h   / v a r / l o g / 2 . l o g   p o s _ f i l e   / v a r / l o g / 2 . l o g . p o s   t a g   c o u n t . f o r m a t 2   < / s o u r c e >   < m a t c h   * * >   t y p e   g o o g l e _ c l o u d   < / m a t c h >


Question: What is Note:?

Answer: T h e   s e c o n d   m a n i f e s t   d e s c r i b e s   a   p o d   t h a t   h a s   a   s i d e c a r   c o n t a i n e r   r u n n i n g   f l u e n t d .   T h e   p o d   m o u n t s   a   v o l u m e   w h e r e   f l u e n t d   c a n   p i c k   u p   i t s   c o n f i g u r a t i o n   d a t a .   a p i V e r s i o n :   v 1   k i n d :   P o d   m e t a d a t a :   n a m e :   c o u n t e r   s p e c :   c o n t a i n e r s :   -   n a m e :   c o u n t   i m a g e :   b u s y b o x : 1 . 2 8   a r g s :   -   / b i n / s h   -   - c   -   >   i = 0 ;   w h i l e   t r u e ;   d o   e c h o   " $ i :   $ ( d a t e ) "   > >   / v a r / l o g / 1 . l o g ;   e c h o   " $ ( d a t e )   I N F O   $ i "   > >   / v a r / l o g / 2 . l o g ;   i = $ ( ( i + 1 ) ) ;   s l e e p   1 ;   d o n e   v o l u m e M o u n t s :   -   n a m e :   v a r l o g   m o u n t P a t h :   / v a r / l o g   -   n a m e :   c o u n t - a g e n t   i m a g e :   r e g i s t r y . k 8 s . i o / f l u e n t d - g c p : 1 . 3 0   e n v :   -   n a m e :   F L U E N T D _ A R G S   v a l u e :   - c   / e t c / f l u e n t d - c o n f i g / f l u e n t d . c o n f   v o l u m e M o u n t s :   -   n a m e :   v a r l o g   m o u n t P a t h :   / v a r / l o g   -   n a m e :   c o n f i g - v o l u m e   m o u n t P a t h :   / e t c / f l u e n t d - c o n f i g   v o l u m e s :   -   n a m e :   v a r l o g   e m p t y D i r :   { }   -   n a m e :   c o n f i g - v o l u m e   c o n f i g M a p :   n a m e :   f l u e n t d - c o n f i g


Question: What is Exposing logs directly from the application?

Answer: C l u s t e r - l o g g i n g   t h a t   e x p o s e s   o r   p u s h e s   l o g s   d i r e c t l y   f r o m   e v e r y   a p p l i c a t i o n   i s   o u t s i d e   t h e   s c o p e   o f   K u b e r n e t e s .


Question: What is What's next?

Answer: R e a d   a b o u t   K u b e r n e t e s   s y s t e m   l o g s L e a r n   a b o u t   T r a c e s   F o r   K u b e r n e t e s   S y s t e m   C o m p o n e n t s L e a r n   h o w   t o   c u s t o m i s e   t h e   t e r m i n a t i o n   m e s s a g e   t h a t   K u b e r n e t e s   r e c o r d s   w h e n   a   P o d   f a i l s


Question: What is Cluster Administration?

Answer: Cluster AdministrationLower-level detail relevant to creating or administering a Kubernetes cluster.The cluster administration overview is for anyone creating or administering a Kubernetes cluster. It assumes some familiarity with core Kubernetes concepts.Planning a clusterSee the guides in Setup for examples of how to plan, set up, and configure Kubernetes clusters. The solutions listed in this article are called distros.Note:Not all distros are actively maintained. Choose distros which have been tested with a recent version of Kubernetes.Before choosing a guide, here are some considerations:Do you want to try out Kubernetes on your computer, or do you want to build a high-availability, multi-node cluster? Choose distros best suited for your needs.Will you be using a hosted Kubernetes cluster, such as Google Kubernetes Engine, or hosting your own cluster?Will your cluster be on-premises, or in the cloud (IaaS)? Kubernetes does not directly support hybrid clusters. Instead, you can set up multiple clusters.If you are configuring Kubernetes on-premises, consider which networking model fits best.Will you be running Kubernetes on "bare metal" hardware or on virtual machines (VMs)?Do you want to run a cluster, or do you expect to do active development of Kubernetes project code? If the latter, choose an actively-developed distro. Some distros only use binary releases, but offer a greater variety of choices.Familiarize yourself with the components needed to run a cluster.Managing a clusterLearn how to manage nodes.Read about Node autoscaling.Learn how to set up and manage the resource quota for shared clusters.Securing a clusterGenerate Certificates describes the steps to generate certificates using different tool chains.Kubernetes Container Environment describes the environment for Kubelet managed containers on a Kubernetes node.Controlling Access to the Kubernetes API describes how Kubernetes implements access control for its own API.Authenticating explains authentication in Kubernetes, including the various authentication options.Authorization is separate from authentication, and controls how HTTP calls are handled.Using Admission Controllers explains plug-ins which intercepts requests to the Kubernetes API server after authentication and authorization.Admission Webhook Good Practices provides good practices and considerations when designing mutating admission webhooks and validating admission webhooks.Using Sysctls in a Kubernetes Cluster describes to an administrator how to use the sysctl command-line tool to set kernel parameters .Auditing describes how to interact with Kubernetes' audit logs.Securing the kubeletControl Plane-Node communicationTLS bootstrappingKubelet authentication/authorizationOptional Cluster ServicesDNS Integration describes how to resolve a DNS name directly to a Kubernetes service.Logging and Monitoring Cluster Activity explains how logging in Kubernetes works and how to implement it.


Question: How does Cluster Administration work?

Answer: Cluster AdministrationLower-level detail relevant to creating or administering a Kubernetes cluster.The cluster administration overview is for anyone creating or administering a Kubernetes cluster. It assumes some familiarity with core Kubernetes concepts.Planning a clusterSee the guides in Setup for examples of how to plan, set up, and configure Kubernetes clusters. The solutions listed in this article are called distros.Note:Not all distros are actively maintained. Choose distros which have been tested with a recent version of Kubernetes.Before choosing a guide, here are some considerations:Do you want to try out Kubernetes on your computer, or do you want to build a high-availability, multi-node cluster? Choose distros best suited for your needs.Will you be using a hosted Kubernetes cluster, such as Google Kubernetes Engine, or hosting your own cluster?Will your cluster be on-premises, or in the cloud (IaaS)? Kubernetes does not directly support hybrid clusters. Instead, you can set up multiple clusters.If you are configuring Kubernetes on-premises, consider which networking model fits best.Will you be running Kubernetes on "bare metal" hardware or on virtual machines (VMs)?Do you want to run a cluster, or do you expect to do active development of Kubernetes project code? If the latter, choose an actively-developed distro. Some distros only use binary releases, but offer a greater variety of choices.Familiarize yourself with the components needed to run a cluster.Managing a clusterLearn how to manage nodes.Read about Node autoscaling.Learn how to set up and manage the resource quota for shared clusters.Securing a clusterGenerate Certificates describes the steps to generate certificates using different tool chains.Kubernetes Container Environment describes the environment for Kubelet managed containers on a Kubernetes node.Controlling Access to the Kubernetes API describes how Kubernetes implements access control for its own API.Authenticating explains authentication in Kubernetes, including the various authentication options.Authorization is separate from authentication, and controls how HTTP calls are handled.Using Admission Controllers explains plug-ins which intercepts requests to the Kubernetes API server after authentication and authorization.Admission Webhook Good Practices provides good practices and considerations when designing mutating admission webhooks and validating admission webhooks.Using Sysctls in a Kubernetes Cluster describes to an administrator how to use the sysctl command-line tool to set kernel parameters .Auditing describes how to interact with Kubernetes' audit logs.Securing the kubeletControl Plane-Node communicationTLS bootstrappingKubelet authentication/authorizationOptional Cluster ServicesDNS Integration describes how to resolve a DNS name directly to a Kubernetes service.Logging and Monitoring Cluster Activity explains how logging in Kubernetes works and how to implement it.


Question: When would you use Cluster Administration?

Answer: Cluster AdministrationLower-level detail relevant to creating or administering a Kubernetes cluster.The cluster administration overview is for anyone creating or administering a Kubernetes cluster. It assumes some familiarity with core Kubernetes concepts.Planning a clusterSee the guides in Setup for examples of how to plan, set up, and configure Kubernetes clusters. The solutions listed in this article are called distros.Note:Not all distros are actively maintained. Choose distros which have been tested with a recent version of Kubernetes.Before choosing a guide, here are some considerations:Do you want to try out Kubernetes on your computer, or do you want to build a high-availability, multi-node cluster? Choose distros best suited for your needs.Will you be using a hosted Kubernetes cluster, such as Google Kubernetes Engine, or hosting your own cluster?Will your cluster be on-premises, or in the cloud (IaaS)? Kubernetes does not directly support hybrid clusters. Instead, you can set up multiple clusters.If you are configuring Kubernetes on-premises, consider which networking model fits best.Will you be running Kubernetes on "bare metal" hardware or on virtual machines (VMs)?Do you want to run a cluster, or do you expect to do active development of Kubernetes project code? If the latter, choose an actively-developed distro. Some distros only use binary releases, but offer a greater variety of choices.Familiarize yourself with the components needed to run a cluster.Managing a clusterLearn how to manage nodes.Read about Node autoscaling.Learn how to set up and manage the resource quota for shared clusters.Securing a clusterGenerate Certificates describes the steps to generate certificates using different tool chains.Kubernetes Container Environment describes the environment for Kubelet managed containers on a Kubernetes node.Controlling Access to the Kubernetes API describes how Kubernetes implements access control for its own API.Authenticating explains authentication in Kubernetes, including the various authentication options.Authorization is separate from authentication, and controls how HTTP calls are handled.Using Admission Controllers explains plug-ins which intercepts requests to the Kubernetes API server after authentication and authorization.Admission Webhook Good Practices provides good practices and considerations when designing mutating admission webhooks and validating admission webhooks.Using Sysctls in a Kubernetes Cluster describes to an administrator how to use the sysctl command-line tool to set kernel parameters .Auditing describes how to interact with Kubernetes' audit logs.Securing the kubeletControl Plane-Node communicationTLS bootstrappingKubelet authentication/authorizationOptional Cluster ServicesDNS Integration describes how to resolve a DNS name directly to a Kubernetes service.Logging and Monitoring Cluster Activity explains how logging in Kubernetes works and how to implement it.


Question: What are the benefits of Cluster Administration?

Answer: Cluster AdministrationLower-level detail relevant to creating or administering a Kubernetes cluster.The cluster administration overview is for anyone creating or administering a Kubernetes cluster. It assumes some familiarity with core Kubernetes concepts.Planning a clusterSee the guides in Setup for examples of how to plan, set up, and configure Kubernetes clusters. The solutions listed in this article are called distros.Note:Not all distros are actively maintained. Choose distros which have been tested with a recent version of Kubernetes.Before choosing a guide, here are some considerations:Do you want to try out Kubernetes on your computer, or do you want to build a high-availability, multi-node cluster? Choose distros best suited for your needs.Will you be using a hosted Kubernetes cluster, such as Google Kubernetes Engine, or hosting your own cluster?Will your cluster be on-premises, or in the cloud (IaaS)? Kubernetes does not directly support hybrid clusters. Instead, you can set up multiple clusters.If you are configuring Kubernetes on-premises, consider which networking model fits best.Will you be running Kubernetes on "bare metal" hardware or on virtual machines (VMs)?Do you want to run a cluster, or do you expect to do active development of Kubernetes project code? If the latter, choose an actively-developed distro. Some distros only use binary releases, but offer a greater variety of choices.Familiarize yourself with the components needed to run a cluster.Managing a clusterLearn how to manage nodes.Read about Node autoscaling.Learn how to set up and manage the resource quota for shared clusters.Securing a clusterGenerate Certificates describes the steps to generate certificates using different tool chains.Kubernetes Container Environment describes the environment for Kubelet managed containers on a Kubernetes node.Controlling Access to the Kubernetes API describes how Kubernetes implements access control for its own API.Authenticating explains authentication in Kubernetes, including the various authentication options.Authorization is separate from authentication, and controls how HTTP calls are handled.Using Admission Controllers explains plug-ins which intercepts requests to the Kubernetes API server after authentication and authorization.Admission Webhook Good Practices provides good practices and considerations when designing mutating admission webhooks and validating admission webhooks.Using Sysctls in a Kubernetes Cluster describes to an administrator how to use the sysctl command-line tool to set kernel parameters .Auditing describes how to interact with Kubernetes' audit logs.Securing the kubeletControl Plane-Node communicationTLS bootstrappingKubelet authentication/authorizationOptional Cluster ServicesDNS Integration describes how to resolve a DNS name directly to a Kubernetes service.Logging and Monitoring Cluster Activity explains how logging in Kubernetes works and how to implement it.


Question: What is Cluster Administration?

Answer: T h e   c l u s t e r   a d m i n i s t r a t i o n   o v e r v i e w   i s   f o r   a n y o n e   c r e a t i n g   o r   a d m i n i s t e r i n g   a   K u b e r n e t e s   c l u s t e r .   I t   a s s u m e s   s o m e   f a m i l i a r i t y   w i t h   c o r e   K u b e r n e t e s   c o n c e p t s .


Question: What is Planning a cluster?

Answer: S e e   t h e   g u i d e s   i n   S e t u p   f o r   e x a m p l e s   o f   h o w   t o   p l a n ,   s e t   u p ,   a n d   c o n f i g u r e   K u b e r n e t e s   c l u s t e r s .   T h e   s o l u t i o n s   l i s t e d   i n   t h i s   a r t i c l e   a r e   c a l l e d   d i s t r o s .


Question: What is Note:?

Answer: B e f o r e   c h o o s i n g   a   g u i d e ,   h e r e   a r e   s o m e   c o n s i d e r a t i o n s :   D o   y o u   w a n t   t o   t r y   o u t   K u b e r n e t e s   o n   y o u r   c o m p u t e r ,   o r   d o   y o u   w a n t   t o   b u i l d   a   h i g h - a v a i l a b i l i t y ,   m u l t i - n o d e   c l u s t e r ?   C h o o s e   d i s t r o s   b e s t   s u i t e d   f o r   y o u r   n e e d s . W i l l   y o u   b e   u s i n g   a   h o s t e d   K u b e r n e t e s   c l u s t e r ,   s u c h   a s   G o o g l e   K u b e r n e t e s   E n g i n e ,   o r   h o s t i n g   y o u r   o w n   c l u s t e r ? W i l l   y o u r   c l u s t e r   b e   o n - p r e m i s e s ,   o r   i n   t h e   c l o u d   ( I a a S ) ?   K u b e r n e t e s   d o e s   n o t   d i r e c t l y   s u p p o r t   h y b r i d   c l u s t e r s .   I n s t e a d ,   y o u   c a n   s e t   u p   m u l t i p l e   c l u s t e r s . I f   y o u   a r e   c o n f i g u r i n g   K u b e r n e t e s   o n - p r e m i s e s ,   c o n s i d e r   w h i c h   n e t w o r k i n g   m o d e l   f i t s   b e s t . W i l l   y o u   b e   r u n n i n g   K u b e r n e t e s   o n   " b a r e   m e t a l "   h a r d w a r e   o r   o n   v i r t u a l   m a c h i n e s   ( V M s ) ? D o   y o u   w a n t   t o   r u n   a   c l u s t e r ,   o r   d o   y o u   e x p e c t   t o   d o   a c t i v e   d e v e l o p m e n t   o f   K u b e r n e t e s   p r o j e c t   c o d e ?   I f   t h e   l a t t e r ,   c h o o s e   a n   a c t i v e l y - d e v e l o p e d   d i s t r o .   S o m e   d i s t r o s   o n l y   u s e   b i n a r y   r e l e a s e s ,   b u t   o f f e r   a   g r e a t e r   v a r i e t y   o f   c h o i c e s . F a m i l i a r i z e   y o u r s e l f   w i t h   t h e   c o m p o n e n t s   n e e d e d   t o   r u n   a   c l u s t e r .


Question: What is Managing a cluster?

Answer: L e a r n   h o w   t o   m a n a g e   n o d e s . R e a d   a b o u t   N o d e   a u t o s c a l i n g . L e a r n   h o w   t o   s e t   u p   a n d   m a n a g e   t h e   r e s o u r c e   q u o t a   f o r   s h a r e d   c l u s t e r s .   L e a r n   h o w   t o   m a n a g e   n o d e s .   R e a d   a b o u t   N o d e   a u t o s c a l i n g .   L e a r n   h o w   t o   s e t   u p   a n d   m a n a g e   t h e   r e s o u r c e   q u o t a   f o r   s h a r e d   c l u s t e r s .


Question: What is Securing a cluster?

Answer: G e n e r a t e   C e r t i f i c a t e s   d e s c r i b e s   t h e   s t e p s   t o   g e n e r a t e   c e r t i f i c a t e s   u s i n g   d i f f e r e n t   t o o l   c h a i n s . K u b e r n e t e s   C o n t a i n e r   E n v i r o n m e n t   d e s c r i b e s   t h e   e n v i r o n m e n t   f o r   K u b e l e t   m a n a g e d   c o n t a i n e r s   o n   a   K u b e r n e t e s   n o d e . C o n t r o l l i n g   A c c e s s   t o   t h e   K u b e r n e t e s   A P I   d e s c r i b e s   h o w   K u b e r n e t e s   i m p l e m e n t s   a c c e s s   c o n t r o l   f o r   i t s   o w n   A P I . A u t h e n t i c a t i n g   e x p l a i n s   a u t h e n t i c a t i o n   i n   K u b e r n e t e s ,   i n c l u d i n g   t h e   v a r i o u s   a u t h e n t i c a t i o n   o p t i o n s . A u t h o r i z a t i o n   i s   s e p a r a t e   f r o m   a u t h e n t i c a t i o n ,   a n d   c o n t r o l s   h o w   H T T P   c a l l s   a r e   h a n d l e d . U s i n g   A d m i s s i o n   C o n t r o l l e r s   e x p l a i n s   p l u g - i n s   w h i c h   i n t e r c e p t s   r e q u e s t s   t o   t h e   K u b e r n e t e s   A P I   s e r v e r   a f t e r   a u t h e n t i c a t i o n   a n d   a u t h o r i z a t i o n . A d m i s s i o n   W e b h o o k   G o o d   P r a c t i c e s   p r o v i d e s   g o o d   p r a c t i c e s   a n d   c o n s i d e r a t i o n s   w h e n   d e s i g n i n g   m u t a t i n g   a d m i s s i o n   w e b h o o k s   a n d   v a l i d a t i n g   a d m i s s i o n   w e b h o o k s . U s i n g   S y s c t l s   i n   a   K u b e r n e t e s   C l u s t e r   d e s c r i b e s   t o   a n   a d m i n i s t r a t o r   h o w   t o   u s e   t h e   s y s c t l   c o m m a n d - l i n e   t o o l   t o   s e t   k e r n e l   p a r a m e t e r s   . A u d i t i n g   d e s c r i b e s   h o w   t o   i n t e r a c t   w i t h   K u b e r n e t e s '   a u d i t   l o g s .   G e n e r a t e


Question: What is Securing the kubelet?

Answer: C o n t r o l   P l a n e - N o d e   c o m m u n i c a t i o n T L S   b o o t s t r a p p i n g K u b e l e t   a u t h e n t i c a t i o n / a u t h o r i z a t i o n


Question: What is Optional Cluster Services?

Answer: D N S   I n t e g r a t i o n   d e s c r i b e s   h o w   t o   r e s o l v e   a   D N S   n a m e   d i r e c t l y   t o   a   K u b e r n e t e s   s e r v i c e . L o g g i n g   a n d   M o n i t o r i n g   C l u s t e r   A c t i v i t y   e x p l a i n s   h o w   l o g g i n g   i n   K u b e r n e t e s   w o r k s   a n d   h o w   t o   i m p l e m e n t   i t .   D N S   I n t e g r a t i o n   d e s c r i b e s   h o w   t o   r e s o l v e   a   D N S   n a m e   d i r e c t l y   t o   a   K u b e r n e t e s   s e r v i c e .   L o g g i n g   a n d   M o n i t o r i n g   C l u s t e r   A c t i v i t y   e x p l a i n s   h o w   l o g g i n g   i n   K u b e r n e t e s   w o r k s   a n d   h o w   t o   i m p l e m e n t   i t .


Question: What is Network Policies?

Answer: Network PoliciesIf you want to control traffic flow at the IP address or port level (OSI layer 3 or 4), NetworkPolicies allow you to specify rules for traffic flow within your cluster, and also between Pods and the outside world. Your cluster must use a network plugin that supports NetworkPolicy enforcement.If you want to control traffic flow at the IP address or port level for TCP, UDP, and SCTP protocols, then you might consider using Kubernetes NetworkPolicies for particular applications in your cluster. NetworkPolicies are an application-centric construct which allow you to specify how a pod is allowed to communicate with various network "entities" (we use the word "entity" here to avoid overloading the more common terms such as "endpoints" and "services", which have specific Kubernetes connotations) over the network. NetworkPolicies apply to a connection with a pod on one or both ends, and are not relevant to other connections.The entities that a Pod can communicate with are identified through a combination of the following three identifiers:Other pods that are allowed (exception: a pod cannot block access to itself)Namespaces that are allowedIP blocks (exception: traffic to and from the node where a Pod is running is always allowed, regardless of the IP address of the Pod or the node)When defining a pod- or namespace-based NetworkPolicy, you use a selector to specify what traffic is allowed to and from the Pod(s) that match the selector.Meanwhile, when IP-based NetworkPolicies are created, we define policies based on IP blocks (CIDR ranges).PrerequisitesNetwork policies are implemented by the network plugin. To use network policies, you must be using a networking solution which supports NetworkPolicy. Creating a NetworkPolicy resource without a controller that implements it will have no effect.The two sorts of pod isolationThere are two sorts of isolation for a pod: isolation for egress, and isolation for ingress. They concern what connections may be established. "Isolation" here is not absolute, rather it means "some restrictions apply". The alternative, "non-isolated for $direction", means that no restrictions apply in the stated direction. The two sorts of isolation (or not) are declared independently, and are both relevant for a connection from one pod to another.By default, a pod is non-isolated for egress; all outbound connections are allowed. A pod is isolated for egress if there is any NetworkPolicy that both selects the pod and has "Egress" in its policyTypes; we say that such a policy applies to the pod for egress. When a pod is isolated for egress, the only allowed connections from the pod are those allowed by the egress list of some NetworkPolicy that applies to the pod for egress. Reply traffic for those allowed connections will also be implicitly allowed. The effects of those egress lists combine additively.By default, a pod is non-isolated for ingress; all inbound connections are allowed. A pod is isolated for ingress if ther


Question: How does Network Policies work?

Answer: Network PoliciesIf you want to control traffic flow at the IP address or port level (OSI layer 3 or 4), NetworkPolicies allow you to specify rules for traffic flow within your cluster, and also between Pods and the outside world. Your cluster must use a network plugin that supports NetworkPolicy enforcement.If you want to control traffic flow at the IP address or port level for TCP, UDP, and SCTP protocols, then you might consider using Kubernetes NetworkPolicies for particular applications in your cluster. NetworkPolicies are an application-centric construct which allow you to specify how a pod is allowed to communicate with various network "entities" (we use the word "entity" here to avoid overloading the more common terms such as "endpoints" and "services", which have specific Kubernetes connotations) over the network. NetworkPolicies apply to a connection with a pod on one or both ends, and are not relevant to other connections.The entities that a Pod can communicate with are identified through a combination of the following three identifiers:Other pods that are allowed (exception: a pod cannot block access to itself)Namespaces that are allowedIP blocks (exception: traffic to and from the node where a Pod is running is always allowed, regardless of the IP address of the Pod or the node)When defining a pod- or namespace-based NetworkPolicy, you use a selector to specify what traffic is allowed to and from the Pod(s) that match the selector.Meanwhile, when IP-based NetworkPolicies are created, we define policies based on IP blocks (CIDR ranges).PrerequisitesNetwork policies are implemented by the network plugin. To use network policies, you must be using a networking solution which supports NetworkPolicy. Creating a NetworkPolicy resource without a controller that implements it will have no effect.The two sorts of pod isolationThere are two sorts of isolation for a pod: isolation for egress, and isolation for ingress. They concern what connections may be established. "Isolation" here is not absolute, rather it means "some restrictions apply". The alternative, "non-isolated for $direction", means that no restrictions apply in the stated direction. The two sorts of isolation (or not) are declared independently, and are both relevant for a connection from one pod to another.By default, a pod is non-isolated for egress; all outbound connections are allowed. A pod is isolated for egress if there is any NetworkPolicy that both selects the pod and has "Egress" in its policyTypes; we say that such a policy applies to the pod for egress. When a pod is isolated for egress, the only allowed connections from the pod are those allowed by the egress list of some NetworkPolicy that applies to the pod for egress. Reply traffic for those allowed connections will also be implicitly allowed. The effects of those egress lists combine additively.By default, a pod is non-isolated for ingress; all inbound connections are allowed. A pod is isolated for ingress if ther


Question: When would you use Network Policies?

Answer: Network PoliciesIf you want to control traffic flow at the IP address or port level (OSI layer 3 or 4), NetworkPolicies allow you to specify rules for traffic flow within your cluster, and also between Pods and the outside world. Your cluster must use a network plugin that supports NetworkPolicy enforcement.If you want to control traffic flow at the IP address or port level for TCP, UDP, and SCTP protocols, then you might consider using Kubernetes NetworkPolicies for particular applications in your cluster. NetworkPolicies are an application-centric construct which allow you to specify how a pod is allowed to communicate with various network "entities" (we use the word "entity" here to avoid overloading the more common terms such as "endpoints" and "services", which have specific Kubernetes connotations) over the network. NetworkPolicies apply to a connection with a pod on one or both ends, and are not relevant to other connections.The entities that a Pod can communicate with are identified through a combination of the following three identifiers:Other pods that are allowed (exception: a pod cannot block access to itself)Namespaces that are allowedIP blocks (exception: traffic to and from the node where a Pod is running is always allowed, regardless of the IP address of the Pod or the node)When defining a pod- or namespace-based NetworkPolicy, you use a selector to specify what traffic is allowed to and from the Pod(s) that match the selector.Meanwhile, when IP-based NetworkPolicies are created, we define policies based on IP blocks (CIDR ranges).PrerequisitesNetwork policies are implemented by the network plugin. To use network policies, you must be using a networking solution which supports NetworkPolicy. Creating a NetworkPolicy resource without a controller that implements it will have no effect.The two sorts of pod isolationThere are two sorts of isolation for a pod: isolation for egress, and isolation for ingress. They concern what connections may be established. "Isolation" here is not absolute, rather it means "some restrictions apply". The alternative, "non-isolated for $direction", means that no restrictions apply in the stated direction. The two sorts of isolation (or not) are declared independently, and are both relevant for a connection from one pod to another.By default, a pod is non-isolated for egress; all outbound connections are allowed. A pod is isolated for egress if there is any NetworkPolicy that both selects the pod and has "Egress" in its policyTypes; we say that such a policy applies to the pod for egress. When a pod is isolated for egress, the only allowed connections from the pod are those allowed by the egress list of some NetworkPolicy that applies to the pod for egress. Reply traffic for those allowed connections will also be implicitly allowed. The effects of those egress lists combine additively.By default, a pod is non-isolated for ingress; all inbound connections are allowed. A pod is isolated for ingress if ther


Question: What are the benefits of Network Policies?

Answer: Network PoliciesIf you want to control traffic flow at the IP address or port level (OSI layer 3 or 4), NetworkPolicies allow you to specify rules for traffic flow within your cluster, and also between Pods and the outside world. Your cluster must use a network plugin that supports NetworkPolicy enforcement.If you want to control traffic flow at the IP address or port level for TCP, UDP, and SCTP protocols, then you might consider using Kubernetes NetworkPolicies for particular applications in your cluster. NetworkPolicies are an application-centric construct which allow you to specify how a pod is allowed to communicate with various network "entities" (we use the word "entity" here to avoid overloading the more common terms such as "endpoints" and "services", which have specific Kubernetes connotations) over the network. NetworkPolicies apply to a connection with a pod on one or both ends, and are not relevant to other connections.The entities that a Pod can communicate with are identified through a combination of the following three identifiers:Other pods that are allowed (exception: a pod cannot block access to itself)Namespaces that are allowedIP blocks (exception: traffic to and from the node where a Pod is running is always allowed, regardless of the IP address of the Pod or the node)When defining a pod- or namespace-based NetworkPolicy, you use a selector to specify what traffic is allowed to and from the Pod(s) that match the selector.Meanwhile, when IP-based NetworkPolicies are created, we define policies based on IP blocks (CIDR ranges).PrerequisitesNetwork policies are implemented by the network plugin. To use network policies, you must be using a networking solution which supports NetworkPolicy. Creating a NetworkPolicy resource without a controller that implements it will have no effect.The two sorts of pod isolationThere are two sorts of isolation for a pod: isolation for egress, and isolation for ingress. They concern what connections may be established. "Isolation" here is not absolute, rather it means "some restrictions apply". The alternative, "non-isolated for $direction", means that no restrictions apply in the stated direction. The two sorts of isolation (or not) are declared independently, and are both relevant for a connection from one pod to another.By default, a pod is non-isolated for egress; all outbound connections are allowed. A pod is isolated for egress if there is any NetworkPolicy that both selects the pod and has "Egress" in its policyTypes; we say that such a policy applies to the pod for egress. When a pod is isolated for egress, the only allowed connections from the pod are those allowed by the egress list of some NetworkPolicy that applies to the pod for egress. Reply traffic for those allowed connections will also be implicitly allowed. The effects of those egress lists combine additively.By default, a pod is non-isolated for ingress; all inbound connections are allowed. A pod is isolated for ingress if ther


Question: What is Network Policies?

Answer: I f   y o u   w a n t   t o   c o n t r o l   t r a f f i c   f l o w   a t   t h e   I P   a d d r e s s   o r   p o r t   l e v e l   f o r   T C P ,   U D P ,   a n d   S C T P   p r o t o c o l s ,   t h e n   y o u   m i g h t   c o n s i d e r   u s i n g   K u b e r n e t e s   N e t w o r k P o l i c i e s   f o r   p a r t i c u l a r   a p p l i c a t i o n s   i n   y o u r   c l u s t e r .   N e t w o r k P o l i c i e s   a r e   a n   a p p l i c a t i o n - c e n t r i c   c o n s t r u c t   w h i c h   a l l o w   y o u   t o   s p e c i f y   h o w   a   p o d   i s   a l l o w e d   t o   c o m m u n i c a t e   w i t h   v a r i o u s   n e t w o r k   " e n t i t i e s "   ( w e   u s e   t h e   w o r d   " e n t i t y "   h e r e   t o   a v o i d   o v e r l o a d i n g   t h e   m o r e   c o m m o n   t e r m s   s u c h   a s   " e n d p o i n t s "   a n d   " s e r v i c e s " ,   w h i c h   h a v e   s p e c i f i c   K u b e r n e t e s   c o n n o t a t i o n s )   o v e r   t h e   n e t w o r k .   N e t w o r k P o l i c i e s   a p p l y   t o   a   c o n n e c t i o n   w i t h   a   p o d   o n   o n e   o r   b o t h   e n d s ,   a n d   a r e   n o t   r e l e v a n t   t o   o t h e r   c o n n e c t i o n s .   T h e   e n t i t i e s   t h a t   a   P o d   c a n   c o m m u n i c a t e   w i t h   a r e   i d e n t i f i e d   t h r o u g h   a   c o m b i n a t i o n   o f   t h e   f o l l o w i n g   t h r e e   i d e n t i f i e r s :   O t h e r   p o d s   t h a t   a r e   a l l o w e d   ( e x c e p t i o n :   a   p o d   c a n n o t   b l o c k   a c c e s s   t o   i t s e l f ) N a m e s p a c e s   t h a t   a r e   a l l o w e d I P   b l o c k s   ( e x c e p t i o n :   t r a f f i c   t o   a n d   f r o m   t h e   n o d e   w h e r e   a   P o d   i s   r u n n i n g   i s   a l w a y s   a l l o w e d ,   r e g a r d l e s s   o f   t h e   I P   a d d r e s s   o f   t h e   P o d   o r   t h e   n


Question: What is Prerequisites?

Answer: N e t w o r k   p o l i c i e s   a r e   i m p l e m e n t e d   b y   t h e   n e t w o r k   p l u g i n .   T o   u s e   n e t w o r k   p o l i c i e s ,   y o u   m u s t   b e   u s i n g   a   n e t w o r k i n g   s o l u t i o n   w h i c h   s u p p o r t s   N e t w o r k P o l i c y .   C r e a t i n g   a   N e t w o r k P o l i c y   r e s o u r c e   w i t h o u t   a   c o n t r o l l e r   t h a t   i m p l e m e n t s   i t   w i l l   h a v e   n o   e f f e c t .


Question: What is The two sorts of pod isolation?

Answer: T h e r e   a r e   t w o   s o r t s   o f   i s o l a t i o n   f o r   a   p o d :   i s o l a t i o n   f o r   e g r e s s ,   a n d   i s o l a t i o n   f o r   i n g r e s s .   T h e y   c o n c e r n   w h a t   c o n n e c t i o n s   m a y   b e   e s t a b l i s h e d .   " I s o l a t i o n "   h e r e   i s   n o t   a b s o l u t e ,   r a t h e r   i t   m e a n s   " s o m e   r e s t r i c t i o n s   a p p l y " .   T h e   a l t e r n a t i v e ,   " n o n - i s o l a t e d   f o r   $ d i r e c t i o n " ,   m e a n s   t h a t   n o   r e s t r i c t i o n s   a p p l y   i n   t h e   s t a t e d   d i r e c t i o n .   T h e   t w o   s o r t s   o f   i s o l a t i o n   ( o r   n o t )   a r e   d e c l a r e d   i n d e p e n d e n t l y ,   a n d   a r e   b o t h   r e l e v a n t   f o r   a   c o n n e c t i o n   f r o m   o n e   p o d   t o   a n o t h e r .   B y   d e f a u l t ,   a   p o d   i s   n o n - i s o l a t e d   f o r   e g r e s s ;   a l l   o u t b o u n d   c o n n e c t i o n s   a r e   a l l o w e d .   A   p o d   i s   i s o l a t e d   f o r   e g r e s s   i f   t h e r e   i s   a n y   N e t w o r k P o l i c y   t h a t   b o t h   s e l e c t s   t h e   p o d   a n d   h a s   " E g r e s s "   i n   i t s   p o l i c y T y p e s ;   w e   s a y   t h a t   s u c h   a   p o l i c y   a p p l i e s   t o   t h e   p o d   f o r   e g r e s s .   W h e n   a   p o d   i s   i s o l a t e d   f o r   e g r e s s ,   t h e   o n l y   a l l o w e d   c o n n e c t i o n s   f r o m   t h e   p o d   a r e   t h o s e   a l l o w e d   b y   t h e   e g r e s s   l i s t   o f   s o m e   N e t w o r k P o l i c y   t h a t   a p p l i e s   t o   t h e   p o d   f o r   e g r e s s .   R e p l y   t r a f f i c   f o r   t h o s e   a l l o w e d   c o n n e c t i o n s   w i l l   a l s o   b e   i m p l i c i t l y   a l l o w e d .   T h e   e f f e c t s   o f   t h o s e   e g r e s s   l i s t s


Question: What is The NetworkPolicy resource?

Answer: S e e   t h e   N e t w o r k P o l i c y   r e f e r e n c e   f o r   a   f u l l   d e f i n i t i o n   o f   t h e   r e s o u r c e .   A n   e x a m p l e   N e t w o r k P o l i c y   m i g h t   l o o k   l i k e   t h i s :   a p i V e r s i o n :   n e t w o r k i n g . k 8 s . i o / v 1   k i n d :   N e t w o r k P o l i c y   m e t a d a t a :   n a m e :   t e s t - n e t w o r k - p o l i c y   n a m e s p a c e :   d e f a u l t   s p e c :   p o d S e l e c t o r :   m a t c h L a b e l s :   r o l e :   d b   p o l i c y T y p e s :   -   I n g r e s s   -   E g r e s s   i n g r e s s :   -   f r o m :   -   i p B l o c k :   c i d r :   1 7 2 . 1 7 . 0 . 0 / 1 6   e x c e p t :   -   1 7 2 . 1 7 . 1 . 0 / 2 4   -   n a m e s p a c e S e l e c t o r :   m a t c h L a b e l s :   p r o j e c t :   m y p r o j e c t   -   p o d S e l e c t o r :   m a t c h L a b e l s :   r o l e :   f r o n t e n d   p o r t s :   -   p r o t o c o l :   T C P   p o r t :   6 3 7 9   e g r e s s :   -   t o :   -   i p B l o c k :   c i d r :   1 0 . 0 . 0 . 0 / 2 4   p o r t s :   -   p r o t o c o l :   T C P   p o r t :   5 9 7 8


Question: What is Note:?

Answer: M a n d a t o r y   F i e l d s :   A s   w i t h   a l l   o t h e r   K u b e r n e t e s   c o n f i g ,   a   N e t w o r k P o l i c y   n e e d s   a p i V e r s i o n ,   k i n d ,   a n d   m e t a d a t a   f i e l d s .   F o r   g e n e r a l   i n f o r m a t i o n   a b o u t   w o r k i n g   w i t h   c o n f i g   f i l e s ,   s e e   C o n f i g u r e   a   P o d   t o   U s e   a   C o n f i g M a p ,   a n d   O b j e c t   M a n a g e m e n t .   s p e c :   N e t w o r k P o l i c y   s p e c   h a s   a l l   t h e   i n f o r m a t i o n   n e e d e d   t o   d e f i n e   a   p a r t i c u l a r   n e t w o r k   p o l i c y   i n   t h e   g i v e n   n a m e s p a c e .   p o d S e l e c t o r :   E a c h   N e t w o r k P o l i c y   i n c l u d e s   a   p o d S e l e c t o r   w h i c h   s e l e c t s   t h e   g r o u p i n g   o f   p o d s   t o   w h i c h   t h e   p o l i c y   a p p l i e s .   T h e   e x a m p l e   p o l i c y   s e l e c t s   p o d s   w i t h   t h e   l a b e l   " r o l e = d b " .   A n   e m p t y   p o d S e l e c t o r   s e l e c t s   a l l   p o d s   i n   t h e   n a m e s p a c e .   p o l i c y T y p e s :   E a c h   N e t w o r k P o l i c y   i n c l u d e s   a   p o l i c y T y p e s   l i s t   w h i c h   m a y   i n c l u d e   e i t h e r   I n g r e s s ,   E g r e s s ,   o r   b o t h .   T h e   p o l i c y T y p e s   f i e l d   i n d i c a t e s   w h e t h e r   o r   n o t   t h e   g i v e n   p o l i c y   a p p l i e s   t o   i n g r e s s   t r a f f i c   t o   s e l e c t e d   p o d ,   e g r e s s   t r a f f i c   f r o m   s e l e c t e d   p o d s ,   o r   b o t h .   I f   n o   p o l i c y T y p e s   a r e   s p e c i f i e d   o n   a   N e t w o r k P o l i c y   t h e n   b y   d e f a u l t   I n g r e s s   w i l l   a l w a y s   b e   s e t   a n d   E g r e s s   w i l l   b e   s e t   i f   t h e   N e t w o r k P o l i c y   h a s   a n y   e g r e


Question: What is Behavior of to and from selectors?

Answer: T h e r e   a r e   f o u r   k i n d s   o f   s e l e c t o r s   t h a t   c a n   b e   s p e c i f i e d   i n   a n   i n g r e s s   f r o m   s e c t i o n   o r   e g r e s s   t o   s e c t i o n :   p o d S e l e c t o r :   T h i s   s e l e c t s   p a r t i c u l a r   P o d s   i n   t h e   s a m e   n a m e s p a c e   a s   t h e   N e t w o r k P o l i c y   w h i c h   s h o u l d   b e   a l l o w e d   a s   i n g r e s s   s o u r c e s   o r   e g r e s s   d e s t i n a t i o n s .   n a m e s p a c e S e l e c t o r :   T h i s   s e l e c t s   p a r t i c u l a r   n a m e s p a c e s   f o r   w h i c h   a l l   P o d s   s h o u l d   b e   a l l o w e d   a s   i n g r e s s   s o u r c e s   o r   e g r e s s   d e s t i n a t i o n s .   n a m e s p a c e S e l e c t o r   a n d   p o d S e l e c t o r :   A   s i n g l e   t o / f r o m   e n t r y   t h a t   s p e c i f i e s   b o t h   n a m e s p a c e S e l e c t o r   a n d   p o d S e l e c t o r   s e l e c t s   p a r t i c u l a r   P o d s   w i t h i n   p a r t i c u l a r   n a m e s p a c e s .   B e   c a r e f u l   t o   u s e   c o r r e c t   Y A M L   s y n t a x .   F o r   e x a m p l e :   . . .   i n g r e s s :   -   f r o m :   -   n a m e s p a c e S e l e c t o r :   m a t c h L a b e l s :   u s e r :   a l i c e   p o d S e l e c t o r :   m a t c h L a b e l s :   r o l e :   c l i e n t   . . .   T h i s   p o l i c y   c o n t a i n s   a   s i n g l e   f r o m   e l e m e n t   a l l o w i n g   c o n n e c t i o n s   f r o m   P o d s   w i t h   t h e   l a b e l   r o l e = c l i e n t   i n   n a m e s p a c e s   w i t h   t h e   l a b e l   u s e r = a l i c e .   B u t   t h e   f o l l o w i n g   p o l i c y   i s   d i f f e r e n t :   . . .   i n g r e s s :   -   f r o m :   -   n a m e s p a c e S e l e c t o r :   m a t c h L a b e l s :   u s e r :   a l i c e   -   p o d S e l e c t o r :   m a t c h L a b e l s :   r o l e :


Question: What is Default policies?

Answer: B y   d e f a u l t ,   i f   n o   p o l i c i e s   e x i s t   i n   a   n a m e s p a c e ,   t h e n   a l l   i n g r e s s   a n d   e g r e s s   t r a f f i c   i s   a l l o w e d   t o   a n d   f r o m   p o d s   i n   t h a t   n a m e s p a c e .   T h e   f o l l o w i n g   e x a m p l e s   l e t   y o u   c h a n g e   t h e   d e f a u l t   b e h a v i o r   i n   t h a t   n a m e s p a c e .


Question: What is Default deny all ingress traffic?

Answer: Y o u   c a n   c r e a t e   a   " d e f a u l t "   i n g r e s s   i s o l a t i o n   p o l i c y   f o r   a   n a m e s p a c e   b y   c r e a t i n g   a   N e t w o r k P o l i c y   t h a t   s e l e c t s   a l l   p o d s   b u t   d o e s   n o t   a l l o w   a n y   i n g r e s s   t r a f f i c   t o   t h o s e   p o d s .   - - -   a p i V e r s i o n :   n e t w o r k i n g . k 8 s . i o / v 1   k i n d :   N e t w o r k P o l i c y   m e t a d a t a :   n a m e :   d e f a u l t - d e n y - i n g r e s s   s p e c :   p o d S e l e c t o r :   { }   p o l i c y T y p e s :   -   I n g r e s s   T h i s   e n s u r e s   t h a t   e v e n   p o d s   t h a t   a r e n ' t   s e l e c t e d   b y   a n y   o t h e r   N e t w o r k P o l i c y   w i l l   s t i l l   b e   i s o l a t e d   f o r   i n g r e s s .   T h i s   p o l i c y   d o e s   n o t   a f f e c t   i s o l a t i o n   f o r   e g r e s s   f r o m   a n y   p o d .


Question: What is Allow all ingress traffic?

Answer: I f   y o u   w a n t   t o   a l l o w   a l l   i n c o m i n g   c o n n e c t i o n s   t o   a l l   p o d s   i n   a   n a m e s p a c e ,   y o u   c a n   c r e a t e   a   p o l i c y   t h a t   e x p l i c i t l y   a l l o w s   t h a t .   - - -   a p i V e r s i o n :   n e t w o r k i n g . k 8 s . i o / v 1   k i n d :   N e t w o r k P o l i c y   m e t a d a t a :   n a m e :   a l l o w - a l l - i n g r e s s   s p e c :   p o d S e l e c t o r :   { }   i n g r e s s :   -   { }   p o l i c y T y p e s :   -   I n g r e s s   W i t h   t h i s   p o l i c y   i n   p l a c e ,   n o   a d d i t i o n a l   p o l i c y   o r   p o l i c i e s   c a n   c a u s e   a n y   i n c o m i n g   c o n n e c t i o n   t o   t h o s e   p o d s   t o   b e   d e n i e d .   T h i s   p o l i c y   h a s   n o   e f f e c t   o n   i s o l a t i o n   f o r   e g r e s s   f r o m   a n y   p o d .