Question: What is Caution:?

Answer: A   F l o w S c h e m a   m a t c h e s   a   g i v e n   r e q u e s t   i f   a t   l e a s t   o n e   o f   i t s   r u l e s   m a t c h e s .   A   r u l e   m a t c h e s   i f   a t   l e a s t   o n e   o f   i t s   s u b j e c t s   a n d   a t   l e a s t   o n e   o f   i t s   r e s o u r c e R u l e s   o r   n o n R e s o u r c e R u l e s   ( d e p e n d i n g   o n   w h e t h e r   t h e   i n c o m i n g   r e q u e s t   i s   f o r   a   r e s o u r c e   o r   n o n - r e s o u r c e   U R L )   m a t c h   t h e   r e q u e s t .   F o r   t h e   n a m e   f i e l d   i n   s u b j e c t s ,   a n d   t h e   v e r b s ,   a p i G r o u p s ,   r e s o u r c e s ,   n a m e s p a c e s ,   a n d   n o n R e s o u r c e U R L s   f i e l d s   o f   r e s o u r c e   a n d   n o n - r e s o u r c e   r u l e s ,   t h e   w i l d c a r d   *   m a y   b e   s p e c i f i e d   t o   m a t c h   a l l   v a l u e s   f o r   t h e   g i v e n   f i e l d ,   e f f e c t i v e l y   r e m o v i n g   i t   f r o m   c o n s i d e r a t i o n .   A   F l o w S c h e m a ' s   d i s t i n g u i s h e r M e t h o d . t y p e   d e t e r m i n e s   h o w   r e q u e s t s   m a t c h i n g   t h a t   s c h e m a   w i l l   b e   s e p a r a t e d   i n t o   f l o w s .   I t   m a y   b e   B y U s e r ,   i n   w h i c h   o n e   r e q u e s t i n g   u s e r   w i l l   n o t   b e   a b l e   t o   s t a r v e   o t h e r   u s e r s   o f   c a p a c i t y ;   B y N a m e s p a c e ,   i n   w h i c h   r e q u e s t s   f o r   r e s o u r c e s   i n   o n e   n a m e s p a c e   w i l l   n o t   b e   a b l e   t o   s t a r v e   r e q u e s t s   f o r   r e s o u r c e s   i n   o t h e r   n a m e s p a c e s   o f   c a p a c i t y ;   o r   b l a n k   ( o r   d i s t i n g u i s h e r M e t h o d   m a y   b e   o m i t t e d   e n t i r e l y ) ,   i n   w h i c h   a l l   r e q u e s t s   m a t c h e d   b y   t h i s   F l


Question: What is Defaults?

Answer: E a c h   k u b e - a p i s e r v e r   m a i n t a i n s   t w o   s o r t s   o f   A P F   c o n f i g u r a t i o n   o b j e c t s :   m a n d a t o r y   a n d   s u g g e s t e d .


Question: What is Mandatory Configuration Objects?

Answer: T h e   f o u r   m a n d a t o r y   c o n f i g u r a t i o n   o b j e c t s   r e f l e c t   f i x e d   b u i l t - i n   g u a r d r a i l   b e h a v i o r .   T h i s   i s   b e h a v i o r   t h a t   t h e   s e r v e r s   h a v e   b e f o r e   t h o s e   o b j e c t s   e x i s t ,   a n d   w h e n   t h o s e   o b j e c t s   e x i s t   t h e i r   s p e c s   r e f l e c t   t h i s   b e h a v i o r .   T h e   f o u r   m a n d a t o r y   o b j e c t s   a r e   a s   f o l l o w s .   T h e   m a n d a t o r y   e x e m p t   p r i o r i t y   l e v e l   i s   u s e d   f o r   r e q u e s t s   t h a t   a r e   n o t   s u b j e c t   t o   f l o w   c o n t r o l   a t   a l l :   t h e y   w i l l   a l w a y s   b e   d i s p a t c h e d   i m m e d i a t e l y .   T h e   m a n d a t o r y   e x e m p t   F l o w S c h e m a   c l a s s i f i e s   a l l   r e q u e s t s   f r o m   t h e   s y s t e m : m a s t e r s   g r o u p   i n t o   t h i s   p r i o r i t y   l e v e l .   Y o u   m a y   d e f i n e   o t h e r   F l o w S c h e m a s   t h a t   d i r e c t   o t h e r   r e q u e s t s   t o   t h i s   p r i o r i t y   l e v e l ,   i f   a p p r o p r i a t e . T h e   m a n d a t o r y   c a t c h - a l l   p r i o r i t y   l e v e l   i s   u s e d   i n   c o m b i n a t i o n   w i t h   t h e   m a n d a t o r y   c a t c h - a l l   F l o w S c h e m a   t o   m a k e   s u r e   t h a t   e v e r y   r e q u e s t   g e t s   s o m e   k i n d   o f   c l a s s i f i c a t i o n .   T y p i c a l l y   y o u   s h o u l d   n o t   r e l y   o n   t h i s   c a t c h - a l l   c o n f i g u r a t i o n ,   a n d   s h o u l d   c r e a t e   y o u r   o w n   c a t c h - a l l   F l o w S c h e m a   a n d   P r i o r i t y L e v e l C o n f i g u r a t i o n   ( o r   u s e   t h e   s u g g e s t e d   g l o b a l - d e f a u l t   p r i o r i t y   l e v e l   t h a t   i s   i n s t a l l e d   b y   d e


Question: What is Suggested Configuration Objects?

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


Question: What is Maintenance of the Mandatory and Suggested Configuration Objects?

Answer: E a c h   k u b e - a p i s e r v e r   i n d e p e n d e n t l y   m a i n t a i n s   t h e   m a n d a t o r y   a n d   s u g g e s t e d   c o n f i g u r a t i o n   o b j e c t s ,   u s i n g   i n i t i a l   a n d   p e r i o d i c   b e h a v i o r .   T h u s ,   i n   a   s i t u a t i o n   w i t h   a   m i x t u r e   o f   s e r v e r s   o f   d i f f e r e n t   v e r s i o n s   t h e r e   m a y   b e   t h r a s h i n g   a s   l o n g   a s   d i f f e r e n t   s e r v e r s   h a v e   d i f f e r e n t   o p i n i o n s   o f   t h e   p r o p e r   c o n t e n t   o f   t h e s e   o b j e c t s .   E a c h   k u b e - a p i s e r v e r   m a k e s   a n   i n i t i a l   m a i n t e n a n c e   p a s s   o v e r   t h e   m a n d a t o r y   a n d   s u g g e s t e d   c o n f i g u r a t i o n   o b j e c t s ,   a n d   a f t e r   t h a t   d o e s   p e r i o d i c   m a i n t e n a n c e   ( o n c e   p e r   m i n u t e )   o f   t h o s e   o b j e c t s .   F o r   t h e   m a n d a t o r y   c o n f i g u r a t i o n   o b j e c t s ,   m a i n t e n a n c e   c o n s i s t s   o f   e n s u r i n g   t h a t   t h e   o b j e c t   e x i s t s   a n d ,   i f   i t   d o e s ,   h a s   t h e   p r o p e r   s p e c .   T h e   s e r v e r   r e f u s e s   t o   a l l o w   a   c r e a t i o n   o r   u p d a t e   w i t h   a   s p e c   t h a t   i s   i n c o n s i s t e n t   w i t h   t h e   s e r v e r ' s   g u a r d r a i l   b e h a v i o r .   M a i n t e n a n c e   o f   s u g g e s t e d   c o n f i g u r a t i o n   o b j e c t s   i s   d e s i g n e d   t o   a l l o w   t h e i r   s p e c s   t o   b e   o v e r r i d d e n .   D e l e t i o n ,   o n   t h e   o t h e r   h a n d ,   i s   n o t   r e s p e c t e d :   m a i n t e n a n c e   w i l l   r e s t o r e   t h e   o b j e c t .   I f   y o u   d o   n o t   w a n t   a   s u g g e s t e d   c o n f i g u r a t i o n   o b j e c t   t h e n   y o


Question: What is Health check concurrency exemption?

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


Question: What is Caution:?

Answer: a p i V e r s i o n :   f l o w c o n t r o l . a p i s e r v e r . k 8 s . i o / v 1   k i n d :   F l o w S c h e m a   m e t a d a t a :   n a m e :   h e a l t h - f o r - s t r a n g e r s   s p e c :   m a t c h i n g P r e c e d e n c e :   1 0 0 0   p r i o r i t y L e v e l C o n f i g u r a t i o n :   n a m e :   e x e m p t   r u l e s :   -   n o n R e s o u r c e R u l e s :   -   n o n R e s o u r c e U R L s :   -   " / h e a l t h z "   -   " / l i v e z "   -   " / r e a d y z "   v e r b s :   -   " * "   s u b j e c t s :   -   k i n d :   G r o u p   g r o u p :   n a m e :   " s y s t e m : u n a u t h e n t i c a t e d "


Question: What is Note:?

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


Question: What is Maturity level BETA?

Answer: a p i s e r v e r _ f l o w c o n t r o l _ r e j e c t e d _ r e q u e s t s _ t o t a l   i s   a   c o u n t e r   v e c t o r   ( c u m u l a t i v e   s i n c e   s e r v e r   s t a r t )   o f   r e q u e s t s   t h a t   w e r e   r e j e c t e d ,   b r o k e n   d o w n   b y   t h e   l a b e l s   f l o w _ s c h e m a   ( i n d i c a t i n g   t h e   o n e   t h a t   m a t c h e d   t h e   r e q u e s t ) ,   p r i o r i t y _ l e v e l   ( i n d i c a t i n g   t h e   o n e   t o   w h i c h   t h e   r e q u e s t   w a s   a s s i g n e d ) ,   a n d   r e a s o n .   T h e   r e a s o n   l a b e l   w i l l   b e   o n e   o f   t h e   f o l l o w i n g   v a l u e s : q u e u e - f u l l ,   i n d i c a t i n g   t h a t   t o o   m a n y   r e q u e s t s   w e r e   a l r e a d y   q u e u e d . c o n c u r r e n c y - l i m i t ,   i n d i c a t i n g   t h a t   t h e   P r i o r i t y L e v e l C o n f i g u r a t i o n   i s   c o n f i g u r e d   t o   r e j e c t   r a t h e r   t h a n   q u e u e   e x c e s s   r e q u e s t s . t i m e - o u t ,   i n d i c a t i n g   t h a t   t h e   r e q u e s t   w a s   s t i l l   i n   t h e   q u e u e   w h e n   i t s   q u e u i n g   t i m e   l i m i t   e x p i r e d . c a n c e l l e d ,   i n d i c a t i n g   t h a t   t h e   r e q u e s t   i s   n o t   p u r g e   l o c k e d   a n d   h a s   b e e n   e j e c t e d   f r o m   t h e   q u e u e . a p i s e r v e r _ f l o w c o n t r o l _ d i s p a t c h e d _ r e q u e s t s _ t o t a l   i s   a   c o u n t e r   v e c t o r   ( c u m u l a t i v e   s i n c e   s e r v e r   s t a r t )   o f   r e q u e s t s   t h a t   b e g a n   e x e c u t i n g ,   b r o k e n   d o w n   b y   f l o w _ s c h e m a   a n d   p r i o r i t y _ l e v e l . a p i s e r v e r _ f l o w c o n t r o l _ c u r r e n t _ i n q u e u e _ r e q u e s t s   i s   a   g a u g e   v e c t o r   h o l d i n g   t h e   i n s t a n t a n e


Question: What is Note:?

Answer: a p i s e r v e r _ f l o w c o n t r o l _ n o m i n a l _ l i m i t _ s e a t s   i s   a   g a u g e   v e c t o r   h o l d i n g   e a c h   p r i o r i t y   l e v e l ' s   n o m i n a l   c o n c u r r e n c y   l i m i t ,   c o m p u t e d   f r o m   t h e   A P I   s e r v e r ' s   t o t a l   c o n c u r r e n c y   l i m i t   a n d   t h e   p r i o r i t y   l e v e l ' s   c o n f i g u r e d   n o m i n a l   c o n c u r r e n c y   s h a r e s .


Question: What is Maturity level ALPHA?

Answer: a p i s e r v e r _ c u r r e n t _ i n q u e u e _ r e q u e s t s   i s   a   g a u g e   v e c t o r   o f   r e c e n t   h i g h   w a t e r   m a r k s   o f   t h e   n u m b e r   o f   q u e u e d   r e q u e s t s ,   g r o u p e d   b y   a   l a b e l   n a m e d   r e q u e s t _ k i n d   w h o s e   v a l u e   i s   m u t a t i n g   o r   r e a d O n l y .   T h e s e   h i g h   w a t e r   m a r k s   d e s c r i b e   t h e   l a r g e s t   n u m b e r   s e e n   i n   t h e   o n e   s e c o n d   w i n d o w   m o s t   r e c e n t l y   c o m p l e t e d .   T h e s e   c o m p l e m e n t   t h e   o l d e r   a p i s e r v e r _ c u r r e n t _ i n f l i g h t _ r e q u e s t s   g a u g e   v e c t o r   t h a t   h o l d s   t h e   l a s t   w i n d o w ' s   h i g h   w a t e r   m a r k   o f   n u m b e r   o f   r e q u e s t s   a c t i v e l y   b e i n g   s e r v e d . a p i s e r v e r _ c u r r e n t _ i n q u e u e _ s e a t s   i s   a   g a u g e   v e c t o r   o f   t h e   s u m   o v e r   q u e u e d   r e q u e s t s   o f   t h e   l a r g e s t   n u m b e r   o f   s e a t s   e a c h   w i l l   o c c u p y ,   g r o u p e d   b y   l a b e l s   n a m e d   f l o w _ s c h e m a   a n d   p r i o r i t y _ l e v e l . a p i s e r v e r _ f l o w c o n t r o l _ r e a d _ v s _ w r i t e _ c u r r e n t _ r e q u e s t s   i s   a   h i s t o g r a m   v e c t o r   o f   o b s e r v a t i o n s ,   m a d e   a t   t h e   e n d   o f   e v e r y   n a n o s e c o n d ,   o f   t h e   n u m b e r   o f   r e q u e s t s   b r o k e n   d o w n   b y   t h e   l a b e l s   p h a s e   ( w h i c h   t a k e s   o n   t h e   v a l u e s   w a i t i n g   a n d   e x e c u t i n g )   a n d   r e q u e s t _ k i n d   ( w h i c h   t a k e s   o n   t h e   v a l u e s   m u t a t i n g   a n d   r e a d O n l y ) .   E a c h   o b s e r v e d   v a l u e   i s   a   r a t i o ,   b e t w e e n   0   a n d   1 ,


Question: What is Note:?

Answer: a p i s e r v e r _ f l o w c o n t r o l _ r e q u e s t _ c o n c u r r e n c y _ l i m i t   i s   t h e   s a m e   a s   a p i s e r v e r _ f l o w c o n t r o l _ n o m i n a l _ l i m i t _ s e a t s .   B e f o r e   t h e   i n t r o d u c t i o n   o f   c o n c u r r e n c y   b o r r o w i n g   b e t w e e n   p r i o r i t y   l e v e l s ,   t h i s   w a s   a l w a y s   e q u a l   t o   a p i s e r v e r _ f l o w c o n t r o l _ c u r r e n t _ l i m i t _ s e a t s   ( w h i c h   d i d   n o t   e x i s t   a s   a   d i s t i n c t   m e t r i c ) .   a p i s e r v e r _ f l o w c o n t r o l _ l o w e r _ l i m i t _ s e a t s   i s   a   g a u g e   v e c t o r   h o l d i n g   t h e   l o w e r   b o u n d   o n   e a c h   p r i o r i t y   l e v e l ' s   d y n a m i c   c o n c u r r e n c y   l i m i t .   a p i s e r v e r _ f l o w c o n t r o l _ u p p e r _ l i m i t _ s e a t s   i s   a   g a u g e   v e c t o r   h o l d i n g   t h e   u p p e r   b o u n d   o n   e a c h   p r i o r i t y   l e v e l ' s   d y n a m i c   c o n c u r r e n c y   l i m i t .   a p i s e r v e r _ f l o w c o n t r o l _ d e m a n d _ s e a t s   i s   a   h i s t o g r a m   v e c t o r   c o u n t i n g   o b s e r v a t i o n s ,   a t   t h e   e n d   o f   e v e r y   n a n o s e c o n d ,   o f   e a c h   p r i o r i t y   l e v e l ' s   r a t i o   o f   ( s e a t   d e m a n d )   /   ( n o m i n a l   c o n c u r r e n c y   l i m i t ) .   A   p r i o r i t y   l e v e l ' s   s e a t   d e m a n d   i s   t h e   s u m ,   o v e r   b o t h   q u e u e d   r e q u e s t s   a n d   t h o s e   i n   t h e   i n i t i a l   p h a s e   o f   e x e c u t i o n ,   o f   t h e   m a x i m u m   o f   t h e   n u m b e r   o f   s e a t s   o c c u p i e d   i n   t h e   r e q u e s t ' s   i n i t i a l   a n d   f i n a l   e x e c u t i o n   p h a s e s .   a p i s e r v e r _ f l o w c o n t r o l _ d e m a n d _ s e a t s _ h


Question: What is Good practices for using API Priority and Fairness?

Answer: W h e n   a   g i v e n   p r i o r i t y   l e v e l   e x c e e d s   i t s   p e r m i t t e d   c o n c u r r e n c y ,   r e q u e s t s   c a n   e x p e r i e n c e   i n c r e a s e d   l a t e n c y   o r   b e   d r o p p e d   w i t h   a n   H T T P   4 2 9   ( T o o   M a n y   R e q u e s t s )   e r r o r .   T o   p r e v e n t   t h e s e   s i d e   e f f e c t s   o f   A P F ,   y o u   c a n   m o d i f y   y o u r   w o r k l o a d   o r   t w e a k   y o u r   A P F   s e t t i n g s   t o   e n s u r e   t h e r e   a r e   s u f f i c i e n t   s e a t s   a v a i l a b l e   t o   s e r v e   y o u r   r e q u e s t s .   T o   d e t e c t   w h e t h e r   r e q u e s t s   a r e   b e i n g   r e j e c t e d   d u e   t o   A P F ,   c h e c k   t h e   f o l l o w i n g   m e t r i c s :   a p i s e r v e r _ f l o w c o n t r o l _ r e j e c t e d _ r e q u e s t s _ t o t a l :   t h e   t o t a l   n u m b e r   o f   r e q u e s t s   r e j e c t e d   p e r   F l o w S c h e m a   a n d   P r i o r i t y L e v e l C o n f i g u r a t i o n . a p i s e r v e r _ f l o w c o n t r o l _ c u r r e n t _ i n q u e u e _ r e q u e s t s :   t h e   c u r r e n t   n u m b e r   o f   r e q u e s t s   q u e u e d   p e r   F l o w S c h e m a   a n d   P r i o r i t y L e v e l C o n f i g u r a t i o n . a p i s e r v e r _ f l o w c o n t r o l _ r e q u e s t _ w a i t _ d u r a t i o n _ s e c o n d s :   t h e   l a t e n c y   a d d e d   t o   r e q u e s t s   w a i t i n g   i n   q u e u e s . a p i s e r v e r _ f l o w c o n t r o l _ p r i o r i t y _ l e v e l _ s e a t _ u t i l i z a t i o n :   t h e   s e a t   u t i l i z a t i o n   p e r   P r i o r i t y L e v e l C o n f i g u r a t i o n .


Question: What is Workload modifications?

Answer: T o   p r e v e n t   r e q u e s t s   f r o m   q u e u i n g   a n d   a d d i n g   l a t e n c y   o r   b e i n g   d r o p p e d   d u e   t o   A P F ,   y o u   c a n   o p t i m i z e   y o u r   r e q u e s t s   b y :   R e d u c i n g   t h e   r a t e   a t   w h i c h   r e q u e s t s   a r e   e x e c u t e d .   A   f e w e r   n u m b e r   o f   r e q u e s t s   o v e r   a   f i x e d   p e r i o d   w i l l   r e s u l t   i n   a   f e w e r   n u m b e r   o f   s e a t s   b e i n g   n e e d e d   a t   a   g i v e n   t i m e . A v o i d   i s s u i n g   a   l a r g e   n u m b e r   o f   e x p e n s i v e   r e q u e s t s   c o n c u r r e n t l y .   R e q u e s t s   c a n   b e   o p t i m i z e d   t o   u s e   f e w e r   s e a t s   o r   h a v e   l o w e r   l a t e n c y   s o   t h a t   t h e s e   r e q u e s t s   h o l d   t h o s e   s e a t s   f o r   a   s h o r t e r   d u r a t i o n .   L i s t   r e q u e s t s   c a n   o c c u p y   m o r e   t h a n   1   s e a t   d e p e n d i n g   o n   t h e   n u m b e r   o f   o b j e c t s   f e t c h e d   d u r i n g   t h e   r e q u e s t .   R e s t r i c t i n g   t h e   n u m b e r   o f   o b j e c t s   r e t r i e v e d   i n   a   l i s t   r e q u e s t ,   f o r   e x a m p l e   b y   u s i n g   p a g i n a t i o n ,   w i l l   u s e   l e s s   t o t a l   s e a t s   o v e r   a   s h o r t e r   p e r i o d .   F u r t h e r m o r e ,   r e p l a c i n g   l i s t   r e q u e s t s   w i t h   w a t c h   r e q u e s t s   w i l l   r e q u i r e   l o w e r   t o t a l   c o n c u r r e n c y   s h a r e s   a s   w a t c h   r e q u e s t s   o n l y   o c c u p y   1   s e a t   d u r i n g   i t s   i n i t i a l   b u r s t   o f   n o t i f i c a t i o n s .   I f   u s i n g   s t r e a m i n g   l i s t s   i n   v e r s i o n s   1 . 2 7   a n d   l a t e r ,   w a t c h   r e q u e s t s   w i l l   o c c u p y   t h e   s a m e   n u m


Question: What is Priority and fairness settings?

Answer: Y o u   c a n   a l s o   m o d i f y   t h e   d e f a u l t   F l o w S c h e m a   a n d   P r i o r i t y L e v e l C o n f i g u r a t i o n   o b j e c t s   o r   c r e a t e   n e w   o b j e c t s   o f   t h e s e   t y p e s   t o   b e t t e r   a c c o m m o d a t e   y o u r   w o r k l o a d .   A P F   s e t t i n g s   c a n   b e   m o d i f i e d   t o :   G i v e   m o r e   s e a t s   t o   h i g h   p r i o r i t y   r e q u e s t s . I s o l a t e   n o n - e s s e n t i a l   o r   e x p e n s i v e   r e q u e s t s   t h a t   w o u l d   s t a r v e   a   c o n c u r r e n c y   l e v e l   i f   i t   w a s   s h a r e d   w i t h   o t h e r   f l o w s .


Question: What is Give more seats to high priority requests?

Answer: I f   p o s s i b l e ,   t h e   n u m b e r   o f   s e a t s   a v a i l a b l e   a c r o s s   a l l   p r i o r i t y   l e v e l s   f o r   a   p a r t i c u l a r   k u b e - a p i s e r v e r   c a n   b e   i n c r e a s e d   b y   i n c r e a s i n g   t h e   v a l u e s   f o r   t h e   m a x - r e q u e s t s - i n f l i g h t   a n d   m a x - m u t a t i n g - r e q u e s t s - i n f l i g h t   f l a g s .   A l t e r n a t i v e l y ,   h o r i z o n t a l l y   s c a l i n g   t h e   n u m b e r   o f   k u b e - a p i s e r v e r   i n s t a n c e s   w i l l   i n c r e a s e   t h e   t o t a l   c o n c u r r e n c y   p e r   p r i o r i t y   l e v e l   a c r o s s   t h e   c l u s t e r   a s s u m i n g   t h e r e   i s   s u f f i c i e n t   l o a d   b a l a n c i n g   o f   r e q u e s t s . Y o u   c a n   c r e a t e   a   n e w   F l o w S c h e m a   w h i c h   r e f e r e n c e s   a   P r i o r i t y L e v e l C o n f i g u r a t i o n   w i t h   a   l a r g e r   c o n c u r r e n c y   l e v e l .   T h i s   n e w   P r i o r i t y L e v e l C o n f i g u r a t i o n   c o u l d   b e   a n   e x i s t i n g   l e v e l   o r   a   n e w   l e v e l   w i t h   i t s   o w n   s e t   o f   n o m i n a l   c o n c u r r e n c y   s h a r e s .   F o r   e x a m p l e ,   a   n e w   F l o w S c h e m a   c o u l d   b e   i n t r o d u c e d   t o   c h a n g e   t h e   P r i o r i t y L e v e l C o n f i g u r a t i o n   f o r   y o u r   r e q u e s t s   f r o m   g l o b a l - d e f a u l t   t o   w o r k l o a d - l o w   t o   i n c r e a s e   t h e   n u m b e r   o f   s e a t s   a v a i l a b l e   t o   y o u r   u s e r .   C r e a t i n g   a   n e w   P r i o r i t y L e v e l C o n f i g u r a t i o n   w i l l   r e d u c e   t h e   n u m b e r   o f   s e a t s   d e s i g n a t e d   f o r   e x i s t i n g   l e v e l s .   R e c a l l   t h a t   e d i t i n g   a   d e f a u l t   F l o w S


Question: What is Isolate non-essential requests from starving other flows?

Answer: F o r   r e q u e s t   i s o l a t i o n ,   y o u   c a n   c r e a t e   a   F l o w S c h e m a   w h o s e   s u b j e c t   m a t c h e s   t h e   u s e r   m a k i n g   t h e s e   r e q u e s t s   o r   c r e a t e   a   F l o w S c h e m a   t h a t   m a t c h e s   w h a t   t h e   r e q u e s t   i s   ( c o r r e s p o n d i n g   t o   t h e   r e s o u r c e R u l e s ) .   N e x t ,   y o u   c a n   m a p   t h i s   F l o w S c h e m a   t o   a   P r i o r i t y L e v e l C o n f i g u r a t i o n   w i t h   a   l o w   s h a r e   o f   s e a t s .   F o r   e x a m p l e ,   s u p p o s e   l i s t   e v e n t   r e q u e s t s   f r o m   P o d s   r u n n i n g   i n   t h e   d e f a u l t   n a m e s p a c e   a r e   u s i n g   1 0   s e a t s   e a c h   a n d   e x e c u t e   f o r   1   m i n u t e .   T o   p r e v e n t   t h e s e   e x p e n s i v e   r e q u e s t s   f r o m   i m p a c t i n g   r e q u e s t s   f r o m   o t h e r   P o d s   u s i n g   t h e   e x i s t i n g   s e r v i c e - a c c o u n t s   F l o w S c h e m a ,   y o u   c a n   a p p l y   t h e   f o l l o w i n g   F l o w S c h e m a   t o   i s o l a t e   t h e s e   l i s t   c a l l s   f r o m   o t h e r   r e q u e s t s .   E x a m p l e   F l o w S c h e m a   o b j e c t   t o   i s o l a t e   l i s t   e v e n t   r e q u e s t s :   a p i V e r s i o n :   f l o w c o n t r o l . a p i s e r v e r . k 8 s . i o / v 1   k i n d :   F l o w S c h e m a   m e t a d a t a :   n a m e :   l i s t - e v e n t s - d e f a u l t - s e r v i c e - a c c o u n t   s p e c :   d i s t i n g u i s h e r M e t h o d :   t y p e :   B y U s e r   m a t c h i n g P r e c e d e n c e :   8 0 0 0   p r i o r i t y L e v e l C o n f i g u r a t i o n :   n a m e :   c a t c h - a l l   r u l e s :   -   r e s o u r c e R u l e s :   -   a p i G r o u p s :   -   ' * '   n a m e s p a c e s :   -   d e f a u l t   r e s o u r c e s :   -   e v e n t


Question: What is What's next?

Answer: Y o u   c a n   v i s i t   f l o w   c o n t r o l   r e f e r e n c e   d o c   t o   l e a r n   m o r e   a b o u t   t r o u b l e s h o o t i n g . F o r   b a c k g r o u n d   i n f o r m a t i o n   o n   d e s i g n   d e t a i l s   f o r   A P I   p r i o r i t y   a n d   f a i r n e s s ,   s e e   t h e   e n h a n c e m e n t   p r o p o s a l . Y o u   c a n   m a k e   s u g g e s t i o n s   a n d   f e a t u r e   r e q u e s t s   v i a   S I G   A P I   M a c h i n e r y   o r   t h e   f e a t u r e ' s   s l a c k   c h a n n e l .


Question: What is 16 - Installing Addons?

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


Question: What is Networking and Network Policy?

Answer: A C I   p r o v i d e s   i n t e g r a t e d   c o n t a i n e r   n e t w o r k i n g   a n d   n e t w o r k   s e c u r i t y   w i t h   C i s c o   A C I . A n t r e a   o p e r a t e s   a t   L a y e r   3 / 4   t o   p r o v i d e   n e t w o r k i n g   a n d   s e c u r i t y   s e r v i c e s   f o r   K u b e r n e t e s ,   l e v e r a g i n g   O p e n   v S w i t c h   a s   t h e   n e t w o r k i n g   d a t a   p l a n e .   A n t r e a   i s   a   C N C F   p r o j e c t   a t   t h e   S a n d b o x   l e v e l . C a l i c o   i s   a   n e t w o r k i n g   a n d   n e t w o r k   p o l i c y   p r o v i d e r .   C a l i c o   s u p p o r t s   a   f l e x i b l e   s e t   o f   n e t w o r k i n g   o p t i o n s   s o   y o u   c a n   c h o o s e   t h e   m o s t   e f f i c i e n t   o p t i o n   f o r   y o u r   s i t u a t i o n ,   i n c l u d i n g   n o n - o v e r l a y   a n d   o v e r l a y   n e t w o r k s ,   w i t h   o r   w i t h o u t   B G P .   C a l i c o   u s e s   t h e   s a m e   e n g i n e   t o   e n f o r c e   n e t w o r k   p o l i c y   f o r   h o s t s ,   p o d s ,   a n d   ( i f   u s i n g   I s t i o   &   E n v o y )   a p p l i c a t i o n s   a t   t h e   s e r v i c e   m e s h   l a y e r . C a n a l   u n i t e s   F l a n n e l   a n d   C a l i c o ,   p r o v i d i n g   n e t w o r k i n g   a n d   n e t w o r k   p o l i c y . C i l i u m   i s   a   n e t w o r k i n g ,   o b s e r v a b i l i t y ,   a n d   s e c u r i t y   s o l u t i o n   w i t h   a n   e B P F - b a s e d   d a t a   p l a n e .   C i l i u m   p r o v i d e s   a   s i m p l e   f l a t   L a y e r   3   n e t w o r k   w i t h   t h e   a b i l i t y   t o   s p a n   m u l t i p l e   c l u s t e r s   i n   e i t h e r   a   n a t i v e   r o u t i n g   o r   o v e r l a y / e n c a p s u l a t i o n   m o d e ,   a n d   c a n   e n f o r c e   n e t w o r k   p o l i c i e s   o n   L 3 - L 7   u s i


Question: What is Service Discovery?

Answer: C o r e D N S   i s   a   f l e x i b l e ,   e x t e n s i b l e   D N S   s e r v e r   w h i c h   c a n   b e   i n s t a l l e d   a s   t h e   i n - c l u s t e r   D N S   f o r   p o d s .


Question: What is Visualization & Control?

Answer: D a s h b o a r d   i s   a   d a s h b o a r d   w e b   i n t e r f a c e   f o r   K u b e r n e t e s .


Question: What is Infrastructure?

Answer: K u b e V i r t   i s   a n   a d d - o n   t o   r u n   v i r t u a l   m a c h i n e s   o n   K u b e r n e t e s .   U s u a l l y   r u n   o n   b a r e - m e t a l   c l u s t e r s . T h e   n o d e   p r o b l e m   d e t e c t o r   r u n s   o n   L i n u x   n o d e s   a n d   r e p o r t s   s y s t e m   i s s u e s   a s   e i t h e r   E v e n t s   o r   N o d e   c o n d i t i o n s .


Question: What is Instrumentation?

Answer: k u b e - s t a t e - m e t r i c s


Question: What is Legacy Add-ons?

Answer: T h e r e   a r e   s e v e r a l   o t h e r   a d d - o n s   d o c u m e n t e d   i n   t h e   d e p r e c a t e d   c l u s t e r / a d d o n s   d i r e c t o r y .   W e l l - m a i n t a i n e d   o n e s   s h o u l d   b e   l i n k e d   t o   h e r e .   P R s   w e l c o m e !


Question: What is 17 - Coordinated Leader Election?

Answer: K u b e r n e t e s   1 . 3 4   i n c l u d e s   a   b e t a   f e a t u r e   t h a t   a l l o w s   c o n t r o l   p l a n e   c o m p o n e n t s   t o   d e t e r m i n i s t i c a l l y   s e l e c t   a   l e a d e r   v i a   c o o r d i n a t e d   l e a d e r   e l e c t i o n .   T h i s   i s   u s e f u l   t o   s a t i s f y   K u b e r n e t e s   v e r s i o n   s k e w   c o n s t r a i n t s   d u r i n g   c l u s t e r   u p g r a d e s .   C u r r e n t l y ,   t h e   o n l y   b u i l t i n   s e l e c t i o n   s t r a t e g y   i s   O l d e s t E m u l a t i o n V e r s i o n ,   p r e f e r r i n g   t h e   l e a d e r   w i t h   t h e   l o w e s t   e m u l a t i o n   v e r s i o n ,   f o l l o w e d   b y   b i n a r y   v e r s i o n ,   f o l l o w e d   b y   c r e a t i o n   t i m e s t a m p .


Question: What is Enabling coordinated leader election?

Answer: E n s u r e   t h a t   C o o r d i n a t e d L e a d e r E l e c t i o n   f e a t u r e   g a t e   i s   e n a b l e d   w h e n   y o u   s t a r t   t h e   A P I   S e r v e r :   a n d   t h a t   t h e   c o o r d i n a t i o n . k 8 s . i o / v 1 b e t a 1   A P I   g r o u p   i s   e n a b l e d .   T h i s   c a n   b e   d o n e   b y   s e t t i n g   f l a g s   - - f e a t u r e - g a t e s = " C o o r d i n a t e d L e a d e r E l e c t i o n = t r u e "   a n d   - - r u n t i m e - c o n f i g = " c o o r d i n a t i o n . k 8 s . i o / v 1 b e t a 1 = t r u e " .


Question: What is Component configuration?

Answer: P r o v i d e d   t h a t   y o u   h a v e   e n a b l e d   t h e   C o o r d i n a t e d L e a d e r E l e c t i o n   f e a t u r e   g a t e   a n d h a v e   t h e   c o o r d i n a t i o n . k 8 s . i o / v 1 b e t a 1   A P I   g r o u p   e n a b l e d ,   c o m p a t i b l e   c o n t r o l   p l a n e c o m p o n e n t s   a u t o m a t i c a l l y   u s e   t h e   L e a s e C a n d i d a t e   a n d   L e a s e   A P I s   t o   e l e c t   a   l e a d e r a s   n e e d e d .   F o r   K u b e r n e t e s   1 . 3 4 ,   t w o   c o n t r o l   p l a n e   c o m p o n e n t s ( k u b e - c o n t r o l l e r - m a n a g e r   a n d   k u b e - s c h e d u l e r )   a u t o m a t i c a l l y   u s e   c o o r d i n a t e d l e a d e r   e l e c t i o n   w h e n   t h e   f e a t u r e   g a t e   a n d   A P I   g r o u p   a r e   e n a b l e d .   ©   2 0 2 5   T h e   K u b e r n e t e s   A u t h o r s   |   D o c u m e n t a t i o n   D i s t r i b u t e d   u n d e r   C C   B Y   4 . 0   ©   2 0 2 5   T h e   L i n u x   F o u n d a t i o n   ® .   A l l   r i g h t s   r e s e r v e d .   T h e   L i n u x   F o u n d a t i o n   h a s   r e g i s t e r e d   t r a d e m a r k s   a n d   u s e s   t r a d e m a r k s .   F o r   a   l i s t   o f   t r a d e m a r k s   o f   T h e   L i n u x   F o u n d a t i o n ,   p l e a s e   s e e   o u r   T r a d e m a r k   U s a g e   p a g e   I C P   l i c e n s e :   京 I C P 备 1 7 0 7 4 2 6 6 号 - 3


Question: What is Runtime Class?

Answer: Runtime ClassFEATURE STATE: Kubernetes v1.20 [stable]This page describes the RuntimeClass resource and runtime selection mechanism.RuntimeClass is a feature for selecting the container runtime configuration. The container runtime configuration is used to run a Pod's containers.MotivationYou can set a different RuntimeClass between different Pods to provide a balance of performance versus security. For example, if part of your workload deserves a high level of information security assurance, you might choose to schedule those Pods so that they run in a container runtime that uses hardware virtualization. You'd then benefit from the extra isolation of the alternative runtime, at the expense of some additional overhead.You can also use RuntimeClass to run different Pods with the same container runtime but with different settings.SetupConfigure the CRI implementation on nodes (runtime dependent)Create the corresponding RuntimeClass resources1. Configure the CRI implementation on nodesThe configurations available through RuntimeClass are Container Runtime Interface (CRI) implementation dependent. See the corresponding documentation (below) for your CRI implementation for how to configure.Note:RuntimeClass assumes a homogeneous node configuration across the cluster by default (which means that all nodes are configured the same way with respect to container runtimes). To support heterogeneous node configurations, see Scheduling below.The configurations have a corresponding handler name, referenced by the RuntimeClass. The handler must be a valid DNS label name.2. Create the corresponding RuntimeClass resourcesThe configurations setup in step 1 should each have an associated handler name, which identifies the configuration. For each handler, create a corresponding RuntimeClass object.The RuntimeClass resource currently only has 2 significant fields: the RuntimeClass name (metadata.name) and the handler (handler). The object definition looks like this:# RuntimeClass is defined in the node.k8s.io API group apiVersion: node.k8s.io/v1 kind: RuntimeClass metadata: # The name the RuntimeClass will be referenced by. # RuntimeClass is a non-namespaced resource. name: myclass # The name of the corresponding CRI configuration handler: myconfiguration The name of a RuntimeClass object must be a valid DNS subdomain name.Note:It is recommended that RuntimeClass write operations (create/update/patch/delete) be restricted to the cluster administrator. This is typically the default. See Authorization Overview for more details.UsageOnce RuntimeClasses are configured for the cluster, you can specify a runtimeClassName in the Pod spec to use it. For example:apiVersion: v1 kind: Pod metadata: name: mypod spec: runtimeClassName: myclass # ... This will instruct the kubelet to use the named RuntimeClass to run this pod. If the named RuntimeClass does not exist, or the CRI cannot run the corresponding handler, the pod will enter the Failed terminal phase. Look for a correspond


Question: How does Runtime Class work?

Answer: Runtime ClassFEATURE STATE: Kubernetes v1.20 [stable]This page describes the RuntimeClass resource and runtime selection mechanism.RuntimeClass is a feature for selecting the container runtime configuration. The container runtime configuration is used to run a Pod's containers.MotivationYou can set a different RuntimeClass between different Pods to provide a balance of performance versus security. For example, if part of your workload deserves a high level of information security assurance, you might choose to schedule those Pods so that they run in a container runtime that uses hardware virtualization. You'd then benefit from the extra isolation of the alternative runtime, at the expense of some additional overhead.You can also use RuntimeClass to run different Pods with the same container runtime but with different settings.SetupConfigure the CRI implementation on nodes (runtime dependent)Create the corresponding RuntimeClass resources1. Configure the CRI implementation on nodesThe configurations available through RuntimeClass are Container Runtime Interface (CRI) implementation dependent. See the corresponding documentation (below) for your CRI implementation for how to configure.Note:RuntimeClass assumes a homogeneous node configuration across the cluster by default (which means that all nodes are configured the same way with respect to container runtimes). To support heterogeneous node configurations, see Scheduling below.The configurations have a corresponding handler name, referenced by the RuntimeClass. The handler must be a valid DNS label name.2. Create the corresponding RuntimeClass resourcesThe configurations setup in step 1 should each have an associated handler name, which identifies the configuration. For each handler, create a corresponding RuntimeClass object.The RuntimeClass resource currently only has 2 significant fields: the RuntimeClass name (metadata.name) and the handler (handler). The object definition looks like this:# RuntimeClass is defined in the node.k8s.io API group apiVersion: node.k8s.io/v1 kind: RuntimeClass metadata: # The name the RuntimeClass will be referenced by. # RuntimeClass is a non-namespaced resource. name: myclass # The name of the corresponding CRI configuration handler: myconfiguration The name of a RuntimeClass object must be a valid DNS subdomain name.Note:It is recommended that RuntimeClass write operations (create/update/patch/delete) be restricted to the cluster administrator. This is typically the default. See Authorization Overview for more details.UsageOnce RuntimeClasses are configured for the cluster, you can specify a runtimeClassName in the Pod spec to use it. For example:apiVersion: v1 kind: Pod metadata: name: mypod spec: runtimeClassName: myclass # ... This will instruct the kubelet to use the named RuntimeClass to run this pod. If the named RuntimeClass does not exist, or the CRI cannot run the corresponding handler, the pod will enter the Failed terminal phase. Look for a correspond


Question: When would you use Runtime Class?

Answer: Runtime ClassFEATURE STATE: Kubernetes v1.20 [stable]This page describes the RuntimeClass resource and runtime selection mechanism.RuntimeClass is a feature for selecting the container runtime configuration. The container runtime configuration is used to run a Pod's containers.MotivationYou can set a different RuntimeClass between different Pods to provide a balance of performance versus security. For example, if part of your workload deserves a high level of information security assurance, you might choose to schedule those Pods so that they run in a container runtime that uses hardware virtualization. You'd then benefit from the extra isolation of the alternative runtime, at the expense of some additional overhead.You can also use RuntimeClass to run different Pods with the same container runtime but with different settings.SetupConfigure the CRI implementation on nodes (runtime dependent)Create the corresponding RuntimeClass resources1. Configure the CRI implementation on nodesThe configurations available through RuntimeClass are Container Runtime Interface (CRI) implementation dependent. See the corresponding documentation (below) for your CRI implementation for how to configure.Note:RuntimeClass assumes a homogeneous node configuration across the cluster by default (which means that all nodes are configured the same way with respect to container runtimes). To support heterogeneous node configurations, see Scheduling below.The configurations have a corresponding handler name, referenced by the RuntimeClass. The handler must be a valid DNS label name.2. Create the corresponding RuntimeClass resourcesThe configurations setup in step 1 should each have an associated handler name, which identifies the configuration. For each handler, create a corresponding RuntimeClass object.The RuntimeClass resource currently only has 2 significant fields: the RuntimeClass name (metadata.name) and the handler (handler). The object definition looks like this:# RuntimeClass is defined in the node.k8s.io API group apiVersion: node.k8s.io/v1 kind: RuntimeClass metadata: # The name the RuntimeClass will be referenced by. # RuntimeClass is a non-namespaced resource. name: myclass # The name of the corresponding CRI configuration handler: myconfiguration The name of a RuntimeClass object must be a valid DNS subdomain name.Note:It is recommended that RuntimeClass write operations (create/update/patch/delete) be restricted to the cluster administrator. This is typically the default. See Authorization Overview for more details.UsageOnce RuntimeClasses are configured for the cluster, you can specify a runtimeClassName in the Pod spec to use it. For example:apiVersion: v1 kind: Pod metadata: name: mypod spec: runtimeClassName: myclass # ... This will instruct the kubelet to use the named RuntimeClass to run this pod. If the named RuntimeClass does not exist, or the CRI cannot run the corresponding handler, the pod will enter the Failed terminal phase. Look for a correspond


Question: What are the benefits of Runtime Class?

Answer: Runtime ClassFEATURE STATE: Kubernetes v1.20 [stable]This page describes the RuntimeClass resource and runtime selection mechanism.RuntimeClass is a feature for selecting the container runtime configuration. The container runtime configuration is used to run a Pod's containers.MotivationYou can set a different RuntimeClass between different Pods to provide a balance of performance versus security. For example, if part of your workload deserves a high level of information security assurance, you might choose to schedule those Pods so that they run in a container runtime that uses hardware virtualization. You'd then benefit from the extra isolation of the alternative runtime, at the expense of some additional overhead.You can also use RuntimeClass to run different Pods with the same container runtime but with different settings.SetupConfigure the CRI implementation on nodes (runtime dependent)Create the corresponding RuntimeClass resources1. Configure the CRI implementation on nodesThe configurations available through RuntimeClass are Container Runtime Interface (CRI) implementation dependent. See the corresponding documentation (below) for your CRI implementation for how to configure.Note:RuntimeClass assumes a homogeneous node configuration across the cluster by default (which means that all nodes are configured the same way with respect to container runtimes). To support heterogeneous node configurations, see Scheduling below.The configurations have a corresponding handler name, referenced by the RuntimeClass. The handler must be a valid DNS label name.2. Create the corresponding RuntimeClass resourcesThe configurations setup in step 1 should each have an associated handler name, which identifies the configuration. For each handler, create a corresponding RuntimeClass object.The RuntimeClass resource currently only has 2 significant fields: the RuntimeClass name (metadata.name) and the handler (handler). The object definition looks like this:# RuntimeClass is defined in the node.k8s.io API group apiVersion: node.k8s.io/v1 kind: RuntimeClass metadata: # The name the RuntimeClass will be referenced by. # RuntimeClass is a non-namespaced resource. name: myclass # The name of the corresponding CRI configuration handler: myconfiguration The name of a RuntimeClass object must be a valid DNS subdomain name.Note:It is recommended that RuntimeClass write operations (create/update/patch/delete) be restricted to the cluster administrator. This is typically the default. See Authorization Overview for more details.UsageOnce RuntimeClasses are configured for the cluster, you can specify a runtimeClassName in the Pod spec to use it. For example:apiVersion: v1 kind: Pod metadata: name: mypod spec: runtimeClassName: myclass # ... This will instruct the kubelet to use the named RuntimeClass to run this pod. If the named RuntimeClass does not exist, or the CRI cannot run the corresponding handler, the pod will enter the Failed terminal phase. Look for a correspond


Question: What is Runtime Class?

Answer: T h i s   p a g e   d e s c r i b e s   t h e   R u n t i m e C l a s s   r e s o u r c e   a n d   r u n t i m e   s e l e c t i o n   m e c h a n i s m .   R u n t i m e C l a s s   i s   a   f e a t u r e   f o r   s e l e c t i n g   t h e   c o n t a i n e r   r u n t i m e   c o n f i g u r a t i o n .   T h e   c o n t a i n e r   r u n t i m e   c o n f i g u r a t i o n   i s   u s e d   t o   r u n   a   P o d ' s   c o n t a i n e r s .


Question: What is Motivation?

Answer: Y o u   c a n   s e t   a   d i f f e r e n t   R u n t i m e C l a s s   b e t w e e n   d i f f e r e n t   P o d s   t o   p r o v i d e   a   b a l a n c e   o f   p e r f o r m a n c e   v e r s u s   s e c u r i t y .   F o r   e x a m p l e ,   i f   p a r t   o f   y o u r   w o r k l o a d   d e s e r v e s   a   h i g h   l e v e l   o f   i n f o r m a t i o n   s e c u r i t y   a s s u r a n c e ,   y o u   m i g h t   c h o o s e   t o   s c h e d u l e   t h o s e   P o d s   s o   t h a t   t h e y   r u n   i n   a   c o n t a i n e r   r u n t i m e   t h a t   u s e s   h a r d w a r e   v i r t u a l i z a t i o n .   Y o u ' d   t h e n   b e n e f i t   f r o m   t h e   e x t r a   i s o l a t i o n   o f   t h e   a l t e r n a t i v e   r u n t i m e ,   a t   t h e   e x p e n s e   o f   s o m e   a d d i t i o n a l   o v e r h e a d .   Y o u   c a n   a l s o   u s e   R u n t i m e C l a s s   t o   r u n   d i f f e r e n t   P o d s   w i t h   t h e   s a m e   c o n t a i n e r   r u n t i m e   b u t   w i t h   d i f f e r e n t   s e t t i n g s .


Question: What is Setup?

Answer: C o n f i g u r e   t h e   C R I   i m p l e m e n t a t i o n   o n   n o d e s   ( r u n t i m e   d e p e n d e n t ) C r e a t e   t h e   c o r r e s p o n d i n g   R u n t i m e C l a s s   r e s o u r c e s


Question: What is 1. Configure the CRI implementation on nodes?

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


Question: What is Note:?

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


Question: What is 2. Create the corresponding RuntimeClass resources?

Answer: T h e   c o n f i g u r a t i o n s   s e t u p   i n   s t e p   1   s h o u l d   e a c h   h a v e   a n   a s s o c i a t e d   h a n d l e r   n a m e ,   w h i c h   i d e n t i f i e s   t h e   c o n f i g u r a t i o n .   F o r   e a c h   h a n d l e r ,   c r e a t e   a   c o r r e s p o n d i n g   R u n t i m e C l a s s   o b j e c t .   T h e   R u n t i m e C l a s s   r e s o u r c e   c u r r e n t l y   o n l y   h a s   2   s i g n i f i c a n t   f i e l d s :   t h e   R u n t i m e C l a s s   n a m e   ( m e t a d a t a . n a m e )   a n d   t h e   h a n d l e r   ( h a n d l e r ) .   T h e   o b j e c t   d e f i n i t i o n   l o o k s   l i k e   t h i s :   #   R u n t i m e C l a s s   i s   d e f i n e d   i n   t h e   n o d e . k 8 s . i o   A P I   g r o u p   a p i V e r s i o n :   n o d e . k 8 s . i o / v 1   k i n d :   R u n t i m e C l a s s   m e t a d a t a :   #   T h e   n a m e   t h e   R u n t i m e C l a s s   w i l l   b e   r e f e r e n c e d   b y .   #   R u n t i m e C l a s s   i s   a   n o n - n a m e s p a c e d   r e s o u r c e .   n a m e :   m y c l a s s   #   T h e   n a m e   o f   t h e   c o r r e s p o n d i n g   C R I   c o n f i g u r a t i o n   h a n d l e r :   m y c o n f i g u r a t i o n   T h e   n a m e   o f   a   R u n t i m e C l a s s   o b j e c t   m u s t   b e   a   v a l i d   D N S   s u b d o m a i n   n a m e .


Question: What is Usage?

Answer: O n c e   R u n t i m e C l a s s e s   a r e   c o n f i g u r e d   f o r   t h e   c l u s t e r ,   y o u   c a n   s p e c i f y   a   r u n t i m e C l a s s N a m e   i n   t h e   P o d   s p e c   t o   u s e   i t .   F o r   e x a m p l e :   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 :   m y p o d   s p e c :   r u n t i m e C l a s s N a m e :   m y c l a s s   #   . . .   T h i s   w i l l   i n s t r u c t   t h e   k u b e l e t   t o   u s e   t h e   n a m e d   R u n t i m e C l a s s   t o   r u n   t h i s   p o d .   I f   t h e   n a m e d   R u n t i m e C l a s s   d o e s   n o t   e x i s t ,   o r   t h e   C R I   c a n n o t   r u n   t h e   c o r r e s p o n d i n g   h a n d l e r ,   t h e   p o d   w i l l   e n t e r   t h e   F a i l e d   t e r m i n a l   p h a s e .   L o o k   f o r   a   c o r r e s p o n d i n g   e v e n t   f o r   a n   e r r o r   m e s s a g e .   I f   n o   r u n t i m e C l a s s N a m e   i s   s p e c i f i e d ,   t h e   d e f a u l t   R u n t i m e H a n d l e r   w i l l   b e   u s e d ,   w h i c h   i s   e q u i v a l e n t   t o   t h e   b e h a v i o r   w h e n   t h e   R u n t i m e C l a s s   f e a t u r e   i s   d i s a b l e d .


Question: What is CRI Configuration?

Answer: F o r   m o r e   d e t a i l s   o n   s e t t i n g   u p   C R I   r u n t i m e s ,   s e e   C R I   i n s t a l l a t i o n .


Question: What is containerd?

Answer: R u n t i m e   h a n d l e r s   a r e   c o n f i g u r e d   t h r o u g h   c o n t a i n e r d ' s   c o n f i g u r a t i o n   a t   / e t c / c o n t a i n e r d / c o n f i g . t o m l .   V a l i d   h a n d l e r s   a r e   c o n f i g u r e d   u n d e r   t h e   r u n t i m e s   s e c t i o n :   [ p l u g i n s . " i o . c o n t a i n e r d . g r p c . v 1 . c r i " . c o n t a i n e r d . r u n t i m e s . $ { H A N D L E R _ N A M E } ]   S e e   c o n t a i n e r d ' s   c o n f i g   d o c u m e n t a t i o n   f o r   m o r e   d e t a i l s :


Question: What is CRI-O?

Answer: R u n t i m e   h a n d l e r s   a r e   c o n f i g u r e d   t h r o u g h   C R I - O ' s   c o n f i g u r a t i o n   a t   / e t c / c r i o / c r i o . c o n f .   V a l i d   h a n d l e r s   a r e   c o n f i g u r e d   u n d e r   t h e   c r i o . r u n t i m e   t a b l e :   [ c r i o . r u n t i m e . r u n t i m e s . $ { H A N D L E R _ N A M E } ]   r u n t i m e _ p a t h   =   " $ { P A T H _ T O _ B I N A R Y } "   S e e   C R I - O ' s   c o n f i g   d o c u m e n t a t i o n   f o r   m o r e   d e t a i l s .


Question: What is Scheduling?

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


Question: What is Pod Overhead?

Answer: Y o u   c a n   s p e c i f y   o v e r h e a d   r e s o u r c e s   t h a t   a r e   a s s o c i a t e d   w i t h   r u n n i n g   a   P o d .   D e c l a r i n g   o v e r h e a d   a l l o w s   t h e   c l u s t e r   ( i n c l u d i n g   t h e   s c h e d u l e r )   t o   a c c o u n t   f o r   i t   w h e n   m a k i n g   d e c i s i o n s   a b o u t   P o d s   a n d   r e s o u r c e s .   P o d   o v e r h e a d   i s   d e f i n e d   i n   R u n t i m e C l a s s   t h r o u g h   t h e   o v e r h e a d   f i e l d .   T h r o u g h   t h e   u s e   o f   t h i s   f i e l d ,   y o u   c a n   s p e c i f y   t h e   o v e r h e a d   o f   r u n n i n g   p o d s   u t i l i z i n g   t h i s   R u n t i m e C l a s s   a n d   e n s u r e   t h e s e   o v e r h e a d s   a r e   a c c o u n t e d   f o r   i n   K u b e r n e t e s .


Question: What is What's next?

Answer: R u n t i m e C l a s s   D e s i g n R u n t i m e C l a s s   S c h e d u l i n g   D e s i g n R e a d   a b o u t   t h e   P o d   O v e r h e a d   c o n c e p t P o d O v e r h e a d   F e a t u r e   D e s i g n


Question: What is Manage Memory, CPU, and API Resources?

Answer: Manage Memory, CPU, and API ResourcesConfigure Default Memory Requests and Limits for a NamespaceDefine a default memory resource limit for a namespace, so that every new Pod in that namespace has a memory resource limit configured.Configure Default CPU Requests and Limits for a NamespaceDefine a default CPU resource limits for a namespace, so that every new Pod in that namespace has a CPU resource limit configured.Configure Minimum and Maximum Memory Constraints for a NamespaceDefine a range of valid memory resource limits for a namespace, so that every new Pod in that namespace falls within the range you configure.Configure Minimum and Maximum CPU Constraints for a NamespaceDefine a range of valid CPU resource limits for a namespace, so that every new Pod in that namespace falls within the range you configure.Configure Memory and CPU Quotas for a NamespaceDefine overall memory and CPU resource limits for a namespace.Configure a Pod Quota for a NamespaceRestrict how many Pods you can create within a namespace.


Question: How does Manage Memory, CPU, and API Resources work?

Answer: Manage Memory, CPU, and API ResourcesConfigure Default Memory Requests and Limits for a NamespaceDefine a default memory resource limit for a namespace, so that every new Pod in that namespace has a memory resource limit configured.Configure Default CPU Requests and Limits for a NamespaceDefine a default CPU resource limits for a namespace, so that every new Pod in that namespace has a CPU resource limit configured.Configure Minimum and Maximum Memory Constraints for a NamespaceDefine a range of valid memory resource limits for a namespace, so that every new Pod in that namespace falls within the range you configure.Configure Minimum and Maximum CPU Constraints for a NamespaceDefine a range of valid CPU resource limits for a namespace, so that every new Pod in that namespace falls within the range you configure.Configure Memory and CPU Quotas for a NamespaceDefine overall memory and CPU resource limits for a namespace.Configure a Pod Quota for a NamespaceRestrict how many Pods you can create within a namespace.


Question: When would you use Manage Memory, CPU, and API Resources?

Answer: Manage Memory, CPU, and API ResourcesConfigure Default Memory Requests and Limits for a NamespaceDefine a default memory resource limit for a namespace, so that every new Pod in that namespace has a memory resource limit configured.Configure Default CPU Requests and Limits for a NamespaceDefine a default CPU resource limits for a namespace, so that every new Pod in that namespace has a CPU resource limit configured.Configure Minimum and Maximum Memory Constraints for a NamespaceDefine a range of valid memory resource limits for a namespace, so that every new Pod in that namespace falls within the range you configure.Configure Minimum and Maximum CPU Constraints for a NamespaceDefine a range of valid CPU resource limits for a namespace, so that every new Pod in that namespace falls within the range you configure.Configure Memory and CPU Quotas for a NamespaceDefine overall memory and CPU resource limits for a namespace.Configure a Pod Quota for a NamespaceRestrict how many Pods you can create within a namespace.


Question: What are the benefits of Manage Memory, CPU, and API Resources?

Answer: Manage Memory, CPU, and API ResourcesConfigure Default Memory Requests and Limits for a NamespaceDefine a default memory resource limit for a namespace, so that every new Pod in that namespace has a memory resource limit configured.Configure Default CPU Requests and Limits for a NamespaceDefine a default CPU resource limits for a namespace, so that every new Pod in that namespace has a CPU resource limit configured.Configure Minimum and Maximum Memory Constraints for a NamespaceDefine a range of valid memory resource limits for a namespace, so that every new Pod in that namespace falls within the range you configure.Configure Minimum and Maximum CPU Constraints for a NamespaceDefine a range of valid CPU resource limits for a namespace, so that every new Pod in that namespace falls within the range you configure.Configure Memory and CPU Quotas for a NamespaceDefine overall memory and CPU resource limits for a namespace.Configure a Pod Quota for a NamespaceRestrict how many Pods you can create within a namespace.


Question: What is Configure Default Memory Requests and Limits for a Namespace?

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


Question: What is Configure Default CPU Requests and Limits for a Namespace?

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


Question: What is Configure Minimum and Maximum Memory Constraints for a Namespace?

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


Question: What is Configure Minimum and Maximum CPU Constraints for a Namespace?

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


Question: What is Configure Memory and CPU Quotas for a Namespace?

Answer: D e f i n e   o v e r a l l   m e m o r y   a n d   C P U   r e s o u r c e   l i m i t s   f o r   a   n a m e s p a c e .


Question: What is Configure a Pod Quota for a Namespace?

Answer: R e s t r i c t   h o w   m a n y   P o d s   y o u   c a n   c r e a t e   w i t h i n   a   n a m e s p a c e .


Question: What is Disruptions?

Answer: DisruptionsThis guide is for application owners who want to build highly available applications, and thus need to understand what types of disruptions can happen to Pods.It is also for cluster administrators who want to perform automated cluster actions, like upgrading and autoscaling clusters.Voluntary and involuntary disruptionsPods do not disappear until someone (a person or a controller) destroys them, or there is an unavoidable hardware or system software error.We call these unavoidable cases involuntary disruptions to an application. Examples are:a hardware failure of the physical machine backing the nodecluster administrator deletes VM (instance) by mistakecloud provider or hypervisor failure makes VM disappeara kernel panicthe node disappears from the cluster due to cluster network partitioneviction of a pod due to the node being out-of-resources.Except for the out-of-resources condition, all these conditions should be familiar to most users; they are not specific to Kubernetes.We call other cases voluntary disruptions. These include both actions initiated by the application owner and those initiated by a Cluster Administrator. Typical application owner actions include:deleting the deployment or other controller that manages the podupdating a deployment's pod template causing a restartdirectly deleting a pod (e.g. by accident)Cluster administrator actions include:Draining a node for repair or upgrade.Draining a node from a cluster to scale the cluster down (learn about Node Autoscaling).Removing a pod from a node to permit something else to fit on that node.These actions might be taken directly by the cluster administrator, or by automation run by the cluster administrator, or by your cluster hosting provider.Ask your cluster administrator or consult your cloud provider or distribution documentation to determine if any sources of voluntary disruptions are enabled for your cluster. If none are enabled, you can skip creating Pod Disruption Budgets.Caution:Not all voluntary disruptions are constrained by Pod Disruption Budgets. For example, deleting deployments or pods bypasses Pod Disruption Budgets.Dealing with disruptionsHere are some ways to mitigate involuntary disruptions:Ensure your pod requests the resources it needs.Replicate your application if you need higher availability. (Learn about running replicated stateless and stateful applications.)For even higher availability when running replicated applications, spread applications across racks (using anti-affinity) or across zones (if using a multi-zone cluster.)The frequency of voluntary disruptions varies. On a basic Kubernetes cluster, there are no automated voluntary disruptions (only user-triggered ones). However, your cluster administrator or hosting provider may run some additional services which cause voluntary disruptions. For example, rolling out node software updates can cause voluntary disruptions. Also, some implementations of cluster (node) autoscaling may cause voluntary


Question: How does Disruptions work?

Answer: DisruptionsThis guide is for application owners who want to build highly available applications, and thus need to understand what types of disruptions can happen to Pods.It is also for cluster administrators who want to perform automated cluster actions, like upgrading and autoscaling clusters.Voluntary and involuntary disruptionsPods do not disappear until someone (a person or a controller) destroys them, or there is an unavoidable hardware or system software error.We call these unavoidable cases involuntary disruptions to an application. Examples are:a hardware failure of the physical machine backing the nodecluster administrator deletes VM (instance) by mistakecloud provider or hypervisor failure makes VM disappeara kernel panicthe node disappears from the cluster due to cluster network partitioneviction of a pod due to the node being out-of-resources.Except for the out-of-resources condition, all these conditions should be familiar to most users; they are not specific to Kubernetes.We call other cases voluntary disruptions. These include both actions initiated by the application owner and those initiated by a Cluster Administrator. Typical application owner actions include:deleting the deployment or other controller that manages the podupdating a deployment's pod template causing a restartdirectly deleting a pod (e.g. by accident)Cluster administrator actions include:Draining a node for repair or upgrade.Draining a node from a cluster to scale the cluster down (learn about Node Autoscaling).Removing a pod from a node to permit something else to fit on that node.These actions might be taken directly by the cluster administrator, or by automation run by the cluster administrator, or by your cluster hosting provider.Ask your cluster administrator or consult your cloud provider or distribution documentation to determine if any sources of voluntary disruptions are enabled for your cluster. If none are enabled, you can skip creating Pod Disruption Budgets.Caution:Not all voluntary disruptions are constrained by Pod Disruption Budgets. For example, deleting deployments or pods bypasses Pod Disruption Budgets.Dealing with disruptionsHere are some ways to mitigate involuntary disruptions:Ensure your pod requests the resources it needs.Replicate your application if you need higher availability. (Learn about running replicated stateless and stateful applications.)For even higher availability when running replicated applications, spread applications across racks (using anti-affinity) or across zones (if using a multi-zone cluster.)The frequency of voluntary disruptions varies. On a basic Kubernetes cluster, there are no automated voluntary disruptions (only user-triggered ones). However, your cluster administrator or hosting provider may run some additional services which cause voluntary disruptions. For example, rolling out node software updates can cause voluntary disruptions. Also, some implementations of cluster (node) autoscaling may cause voluntary


Question: When would you use Disruptions?

Answer: DisruptionsThis guide is for application owners who want to build highly available applications, and thus need to understand what types of disruptions can happen to Pods.It is also for cluster administrators who want to perform automated cluster actions, like upgrading and autoscaling clusters.Voluntary and involuntary disruptionsPods do not disappear until someone (a person or a controller) destroys them, or there is an unavoidable hardware or system software error.We call these unavoidable cases involuntary disruptions to an application. Examples are:a hardware failure of the physical machine backing the nodecluster administrator deletes VM (instance) by mistakecloud provider or hypervisor failure makes VM disappeara kernel panicthe node disappears from the cluster due to cluster network partitioneviction of a pod due to the node being out-of-resources.Except for the out-of-resources condition, all these conditions should be familiar to most users; they are not specific to Kubernetes.We call other cases voluntary disruptions. These include both actions initiated by the application owner and those initiated by a Cluster Administrator. Typical application owner actions include:deleting the deployment or other controller that manages the podupdating a deployment's pod template causing a restartdirectly deleting a pod (e.g. by accident)Cluster administrator actions include:Draining a node for repair or upgrade.Draining a node from a cluster to scale the cluster down (learn about Node Autoscaling).Removing a pod from a node to permit something else to fit on that node.These actions might be taken directly by the cluster administrator, or by automation run by the cluster administrator, or by your cluster hosting provider.Ask your cluster administrator or consult your cloud provider or distribution documentation to determine if any sources of voluntary disruptions are enabled for your cluster. If none are enabled, you can skip creating Pod Disruption Budgets.Caution:Not all voluntary disruptions are constrained by Pod Disruption Budgets. For example, deleting deployments or pods bypasses Pod Disruption Budgets.Dealing with disruptionsHere are some ways to mitigate involuntary disruptions:Ensure your pod requests the resources it needs.Replicate your application if you need higher availability. (Learn about running replicated stateless and stateful applications.)For even higher availability when running replicated applications, spread applications across racks (using anti-affinity) or across zones (if using a multi-zone cluster.)The frequency of voluntary disruptions varies. On a basic Kubernetes cluster, there are no automated voluntary disruptions (only user-triggered ones). However, your cluster administrator or hosting provider may run some additional services which cause voluntary disruptions. For example, rolling out node software updates can cause voluntary disruptions. Also, some implementations of cluster (node) autoscaling may cause voluntary


Question: What are the benefits of Disruptions?

Answer: DisruptionsThis guide is for application owners who want to build highly available applications, and thus need to understand what types of disruptions can happen to Pods.It is also for cluster administrators who want to perform automated cluster actions, like upgrading and autoscaling clusters.Voluntary and involuntary disruptionsPods do not disappear until someone (a person or a controller) destroys them, or there is an unavoidable hardware or system software error.We call these unavoidable cases involuntary disruptions to an application. Examples are:a hardware failure of the physical machine backing the nodecluster administrator deletes VM (instance) by mistakecloud provider or hypervisor failure makes VM disappeara kernel panicthe node disappears from the cluster due to cluster network partitioneviction of a pod due to the node being out-of-resources.Except for the out-of-resources condition, all these conditions should be familiar to most users; they are not specific to Kubernetes.We call other cases voluntary disruptions. These include both actions initiated by the application owner and those initiated by a Cluster Administrator. Typical application owner actions include:deleting the deployment or other controller that manages the podupdating a deployment's pod template causing a restartdirectly deleting a pod (e.g. by accident)Cluster administrator actions include:Draining a node for repair or upgrade.Draining a node from a cluster to scale the cluster down (learn about Node Autoscaling).Removing a pod from a node to permit something else to fit on that node.These actions might be taken directly by the cluster administrator, or by automation run by the cluster administrator, or by your cluster hosting provider.Ask your cluster administrator or consult your cloud provider or distribution documentation to determine if any sources of voluntary disruptions are enabled for your cluster. If none are enabled, you can skip creating Pod Disruption Budgets.Caution:Not all voluntary disruptions are constrained by Pod Disruption Budgets. For example, deleting deployments or pods bypasses Pod Disruption Budgets.Dealing with disruptionsHere are some ways to mitigate involuntary disruptions:Ensure your pod requests the resources it needs.Replicate your application if you need higher availability. (Learn about running replicated stateless and stateful applications.)For even higher availability when running replicated applications, spread applications across racks (using anti-affinity) or across zones (if using a multi-zone cluster.)The frequency of voluntary disruptions varies. On a basic Kubernetes cluster, there are no automated voluntary disruptions (only user-triggered ones). However, your cluster administrator or hosting provider may run some additional services which cause voluntary disruptions. For example, rolling out node software updates can cause voluntary disruptions. Also, some implementations of cluster (node) autoscaling may cause voluntary


Question: What is Disruptions?

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


Question: What is Voluntary and involuntary disruptions?

Answer: P o d s   d o   n o t   d i s a p p e a r   u n t i l   s o m e o n e   ( a   p e r s o n   o r   a   c o n t r o l l e r )   d e s t r o y s   t h e m ,   o r   t h e r e   i s   a n   u n a v o i d a b l e   h a r d w a r e   o r   s y s t e m   s o f t w a r e   e r r o r .   W e   c a l l   t h e s e   u n a v o i d a b l e   c a s e s   i n v o l u n t a r y   d i s r u p t i o n s   t o   a n   a p p l i c a t i o n .   E x a m p l e s   a r e :   a   h a r d w a r e   f a i l u r e   o f   t h e   p h y s i c a l   m a c h i n e   b a c k i n g   t h e   n o d e c l u s t e r   a d m i n i s t r a t o r   d e l e t e s   V M   ( i n s t a n c e )   b y   m i s t a k e c l o u d   p r o v i d e r   o r   h y p e r v i s o r   f a i l u r e   m a k e s   V M   d i s a p p e a r a   k e r n e l   p a n i c t h e   n o d e   d i s a p p e a r s   f r o m   t h e   c l u s t e r   d u e   t o   c l u s t e r   n e t w o r k   p a r t i t i o n e v i c t i o n   o f   a   p o d   d u e   t o   t h e   n o d e   b e i n g   o u t - o f - r e s o u r c e s .   E x c e p t   f o r   t h e   o u t - o f - r e s o u r c e s   c o n d i t i o n ,   a l l   t h e s e   c o n d i t i o n s   s h o u l d   b e   f a m i l i a r   t o   m o s t   u s e r s ;   t h e y   a r e   n o t   s p e c i f i c   t o   K u b e r n e t e s .   W e   c a l l   o t h e r   c a s e s   v o l u n t a r y   d i s r u p t i o n s .   T h e s e   i n c l u d e   b o t h   a c t i o n s   i n i t i a t e d   b y   t h e   a p p l i c a t i o n   o w n e r   a n d   t h o s e   i n i t i a t e d   b y   a   C l u s t e r   A d m i n i s t r a t o r .   T y p i c a l   a p p l i c a t i o n   o w n e r   a c t i o n s   i n c l u d e :   d e l e t i n g   t h e   d e p l o y m e n t   o r   o t h e r   c o n t r o l l e r   t h a t   m a n a g e s   t h e   p o d u p d a t i n g   a   d e p l o y m e n t ' s   p o d   t e m p l a t e   c a u s i n g   a   r e s t a r t d i r e c t l y   d e l e


Question: What is Dealing with disruptions?

Answer: H e r e   a r e   s o m e   w a y s   t o   m i t i g a t e   i n v o l u n t a r y   d i s r u p t i o n s :   E n s u r e   y o u r   p o d   r e q u e s t s   t h e   r e s o u r c e s   i t   n e e d s . R e p l i c a t e   y o u r   a p p l i c a t i o n   i f   y o u   n e e d   h i g h e r   a v a i l a b i l i t y .   ( L e a r n   a b o u t   r u n n i n g   r e p l i c a t e d   s t a t e l e s s   a n d   s t a t e f u l   a p p l i c a t i o n s . ) F o r   e v e n   h i g h e r   a v a i l a b i l i t y   w h e n   r u n n i n g   r e p l i c a t e d   a p p l i c a t i o n s ,   s p r e a d   a p p l i c a t i o n s   a c r o s s   r a c k s   ( u s i n g   a n t i - a f f i n i t y )   o r   a c r o s s   z o n e s   ( i f   u s i n g   a   m u l t i - z o n e   c l u s t e r . )   T h e   f r e q u e n c y   o f   v o l u n t a r y   d i s r u p t i o n s   v a r i e s .   O n   a   b a s i c   K u b e r n e t e s   c l u s t e r ,   t h e r e   a r e   n o   a u t o m a t e d   v o l u n t a r y   d i s r u p t i o n s   ( o n l y   u s e r - t r i g g e r e d   o n e s ) .   H o w e v e r ,   y o u r   c l u s t e r   a d m i n i s t r a t o r   o r   h o s t i n g   p r o v i d e r   m a y   r u n   s o m e   a d d i t i o n a l   s e r v i c e s   w h i c h   c a u s e   v o l u n t a r y   d i s r u p t i o n s .   F o r   e x a m p l e ,   r o l l i n g   o u t   n o d e   s o f t w a r e   u p d a t e s   c a n   c a u s e   v o l u n t a r y   d i s r u p t i o n s .   A l s o ,   s o m e   i m p l e m e n t a t i o n s   o f   c l u s t e r   ( n o d e )   a u t o s c a l i n g   m a y   c a u s e   v o l u n t a r y   d i s r u p t i o n s   t o   d e f r a g m e n t   a n d   c o m p a c t   n o d e s .   Y o u r   c l u s t e r   a d m i n i s t r a t o r   o r   h o s t i n g   p r o v i d e r   s h o u l d   h a v e   d o c u m e n t e d   w h a t   l e v e l   o f   v o l u n t a r y   d i s r u p t i o n s ,   i f   a n y ,   t o   e


Question: What is Pod disruption budgets?

Answer: K u b e r n e t e s   o f f e r s   f e a t u r e s   t o   h e l p   y o u   r u n   h i g h l y   a v a i l a b l e   a p p l i c a t i o n s   e v e n   w h e n   y o u   i n t r o d u c e   f r e q u e n t   v o l u n t a r y   d i s r u p t i o n s .   A s   a n   a p p l i c a t i o n   o w n e r ,   y o u   c a n   c r e a t e   a   P o d D i s r u p t i o n B u d g e t   ( P D B )   f o r   e a c h   a p p l i c a t i o n .   A   P D B   l i m i t s   t h e   n u m b e r   o f   P o d s   o f   a   r e p l i c a t e d   a p p l i c a t i o n   t h a t   a r e   d o w n   s i m u l t a n e o u s l y   f r o m   v o l u n t a r y   d i s r u p t i o n s .   F o r   e x a m p l e ,   a   q u o r u m - b a s e d   a p p l i c a t i o n   w o u l d   l i k e   t o   e n s u r e   t h a t   t h e   n u m b e r   o f   r e p l i c a s   r u n n i n g   i s   n e v e r   b r o u g h t   b e l o w   t h e   n u m b e r   n e e d e d   f o r   a   q u o r u m .   A   w e b   f r o n t   e n d   m i g h t   w a n t   t o   e n s u r e   t h a t   t h e   n u m b e r   o f   r e p l i c a s   s e r v i n g   l o a d   n e v e r   f a l l s   b e l o w   a   c e r t a i n   p e r c e n t a g e   o f   t h e   t o t a l .   C l u s t e r   m a n a g e r s   a n d   h o s t i n g   p r o v i d e r s   s h o u l d   u s e   t o o l s   w h i c h   r e s p e c t   P o d D i s r u p t i o n B u d g e t s   b y   c a l l i n g   t h e   E v i c t i o n   A P I   i n s t e a d   o f   d i r e c t l y   d e l e t i n g   p o d s   o r   d e p l o y m e n t s .   F o r   e x a m p l e ,   t h e   k u b e c t l   d r a i n   s u b c o m m a n d   l e t s   y o u   m a r k   a   n o d e   a s   g o i n g   o u t   o f   s e r v i c e .   W h e n   y o u   r u n   k u b e c t l   d r a i n ,   t h e   t o o l   t r i e s   t o   e v i c t   a l l   o f   t h e   P o d s   o n   t h e   N o d e   y o u ' r e   t a k i n g   o u t   o f   s e r v i c e .   T h e   e v i c t i o n   r


Question: What is PodDisruptionBudget example?

Answer: C o n s i d e r   a   c l u s t e r   w i t h   3   n o d e s ,   n o d e - 1   t h r o u g h   n o d e - 3 .   T h e   c l u s t e r   i s   r u n n i n g   s e v e r a l   a p p l i c a t i o n s .   O n e   o f   t h e m   h a s   3   r e p l i c a s   i n i t i a l l y   c a l l e d   p o d - a ,   p o d - b ,   a n d   p o d - c .   A n o t h e r ,   u n r e l a t e d   p o d   w i t h o u t   a   P D B ,   c a l l e d   p o d - x ,   i s   a l s o   s h o w n .   I n i t i a l l y ,   t h e   p o d s   a r e   l a i d   o u t   a s   f o l l o w s :   A l l   3   p o d s   a r e   p a r t   o f   a   d e p l o y m e n t ,   a n d   t h e y   c o l l e c t i v e l y   h a v e   a   P D B   w h i c h   r e q u i r e s   t h e r e   b e   a t   l e a s t   2   o f   t h e   3   p o d s   t o   b e   a v a i l a b l e   a t   a l l   t i m e s .   F o r   e x a m p l e ,   a s s u m e   t h e   c l u s t e r   a d m i n i s t r a t o r   w a n t s   t o   r e b o o t   i n t o   a   n e w   k e r n e l   v e r s i o n   t o   f i x   a   b u g   i n   t h e   k e r n e l .   T h e   c l u s t e r   a d m i n i s t r a t o r   f i r s t   t r i e s   t o   d r a i n   n o d e - 1   u s i n g   t h e   k u b e c t l   d r a i n   c o m m a n d .   T h a t   t o o l   t r i e s   t o   e v i c t   p o d - a   a n d   p o d - x .   T h i s   s u c c e e d s   i m m e d i a t e l y .   B o t h   p o d s   g o   i n t o   t h e   t e r m i n a t i n g   s t a t e   a t   t h e   s a m e   t i m e .   T h i s   p u t s   t h e   c l u s t e r   i n   t h i s   s t a t e :   T h e   d e p l o y m e n t   n o t i c e s   t h a t   o n e   o f   t h e   p o d s   i s   t e r m i n a t i n g ,   s o   i t   c r e a t e s   a   r e p l a c e m e n t   c a l l e d   p o d - d .   S i n c e   n o d e - 1   i s   c o r d o n e d ,   i t   l a n d s   o n   a n o t h e r   n o d e .   S o m e t h i n g   h a s   a l s o   c r e a t e d   p o d - y   a s   a   r e p l a c e m e n


Question: What is Pod disruption conditions?

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


Question: What is Note:?

Answer: A l o n g   w i t h   c l e a n i n g   u p   t h e   p o d s ,   t h e   P o d   g a r b a g e   c o l l e c t o r   ( P o d G C )   w i l l   a l s o   m a r k   t h e m   a s   f a i l e d   i f   t h e y   a r e   i n   a   n o n - t e r m i n a l   p h a s e   ( s e e   a l s o   P o d   g a r b a g e   c o l l e c t i o n ) .   W h e n   u s i n g   a   J o b   ( o r   C r o n J o b ) ,   y o u   m a y   w a n t   t o   u s e   t h e s e   P o d   d i s r u p t i o n   c o n d i t i o n s   a s   p a r t   o f   y o u r   J o b ' s   P o d   f a i l u r e   p o l i c y .


Question: What is Separating Cluster Owner and Application Owner Roles?

Answer: O f t e n ,   i t   i s   u s e f u l   t o   t h i n k   o f   t h e   C l u s t e r   M a n a g e r   a n d   A p p l i c a t i o n   O w n e r   a s   s e p a r a t e   r o l e s   w i t h   l i m i t e d   k n o w l e d g e   o f   e a c h   o t h e r .   T h i s   s e p a r a t i o n   o f   r e s p o n s i b i l i t i e s   m a y   m a k e   s e n s e   i n   t h e s e   s c e n a r i o s :   w h e n   t h e r e   a r e   m a n y   a p p l i c a t i o n   t e a m s   s h a r i n g   a   K u b e r n e t e s   c l u s t e r ,   a n d   t h e r e   i s   n a t u r a l   s p e c i a l i z a t i o n   o f   r o l e s w h e n   t h i r d - p a r t y   t o o l s   o r   s e r v i c e s   a r e   u s e d   t o   a u t o m a t e   c l u s t e r   m a n a g e m e n t   P o d   D i s r u p t i o n   B u d g e t s   s u p p o r t   t h i s   s e p a r a t i o n   o f   r o l e s   b y   p r o v i d i n g   a n   i n t e r f a c e   b e t w e e n   t h e   r o l e s .   I f   y o u   d o   n o t   h a v e   s u c h   a   s e p a r a t i o n   o f   r e s p o n s i b i l i t i e s   i n   y o u r   o r g a n i z a t i o n ,   y o u   m a y   n o t   n e e d   t o   u s e   P o d   D i s r u p t i o n   B u d g e t s .


Question: What is How to perform Disruptive Actions on your Cluster?

Answer: I f   y o u   a r e   a   C l u s t e r   A d m i n i s t r a t o r ,   a n d   y o u   n e e d   t o   p e r f o r m   a   d i s r u p t i v e   a c t i o n   o n   a l l   t h e   n o d e s   i n   y o u r   c l u s t e r ,   s u c h   a s   a   n o d e   o r   s y s t e m   s o f t w a r e   u p g r a d e ,   h e r e   a r e   s o m e   o p t i o n s :   A c c e p t   d o w n t i m e   d u r i n g   t h e   u p g r a d e . F a i l o v e r   t o   a n o t h e r   c o m p l e t e   r e p l i c a   c l u s t e r . N o   d o w n t i m e ,   b u t   m a y   b e   c o s t l y   b o t h   f o r   t h e   d u p l i c a t e d   n o d e s   a n d   f o r   h u m a n   e f f o r t   t o   o r c h e s t r a t e   t h e   s w i t c h o v e r . W r i t e   d i s r u p t i o n   t o l e r a n t   a p p l i c a t i o n s   a n d   u s e   P D B s . N o   d o w n t i m e . M i n i m a l   r e s o u r c e   d u p l i c a t i o n . A l l o w s   m o r e   a u t o m a t i o n   o f   c l u s t e r   a d m i n i s t r a t i o n . W r i t i n g   d i s r u p t i o n - t o l e r a n t   a p p l i c a t i o n s   i s   t r i c k y ,   b u t   t h e   w o r k   t o   t o l e r a t e   v o l u n t a r y   d i s r u p t i o n s   l a r g e l y   o v e r l a p s   w i t h   w o r k   t o   s u p p o r t   a u t o s c a l i n g   a n d   t o l e r a t i n g   i n v o l u n t a r y   d i s r u p t i o n s .   N o   d o w n t i m e ,   b u t   m a y   b e   c o s t l y   b o t h   f o r   t h e   d u p l i c a t e d   n o d e s   a n d   f o r   h u m a n   e f f o r t   t o   o r c h e s t r a t e   t h e   s w i t c h o v e r .   N o   d o w n t i m e . M i n i m a l   r e s o u r c e   d u p l i c a t i o n . A l l o w s   m o r e   a u t o m a t i o n   o f   c l u s t e r   a d m i n i s t r a t i o n . W r i t i n g   d i s r u p t i o n - t o l e r a n t   a p p l i c a t i o n s   i s   t r i c k y ,   b u t   t h e   w o r k   t o   t o l e r a t e   v o l u n t a r y   d i s r u p t


Question: What is What's next?

Answer: F o l l o w   s t e p s   t o   p r o t e c t   y o u r   a p p l i c a t i o n   b y   c o n f i g u r i n g   a   P o d   D i s r u p t i o n   B u d g e t . L e a r n   m o r e   a b o u t   d r a i n i n g   n o d e s L e a r n   a b o u t   u p d a t i n g   a   d e p l o y m e n t   i n c l u d i n g   s t e p s   t o   m a i n t a i n   i t s   a v a i l a b i l i t y   d u r i n g   t h e   r o l l o u t .   F o l l o w   s t e p s   t o   p r o t e c t   y o u r   a p p l i c a t i o n   b y   c o n f i g u r i n g   a   P o d   D i s r u p t i o n   B u d g e t .   L e a r n   m o r e   a b o u t   d r a i n i n g   n o d e s   L e a r n   a b o u t   u p d a t i n g   a   d e p l o y m e n t   i n c l u d i n g   s t e p s   t o   m a i n t a i n   i t s   a v a i l a b i l i t y   d u r i n g   t h e   r o l l o u t .


Question: What is Using Minikube to Create a Cluster?

Answer: Using Minikube to Create a ClusterObjectivesLearn what a Kubernetes cluster is.Learn what Minikube is.Start a Kubernetes cluster on your computer.Kubernetes ClustersKubernetes is a production-grade, open-source platform that orchestrates the placement (scheduling) and execution of application containers within and across computer clusters.Kubernetes coordinates a highly available cluster of computers that are connected to work as a single unit. The abstractions in Kubernetes allow you to deploy containerized applications to a cluster without tying them specifically to individual machines. To make use of this new model of deployment, applications need to be packaged in a way that decouples them from individual hosts: they need to be containerized. Containerized applications are more flexible and available than in past deployment models, where applications were installed directly onto specific machines as packages deeply integrated into the host. Kubernetes automates the distribution and scheduling of application containers across a cluster in a more efficient way. Kubernetes is an open-source platform and is production-ready.A Kubernetes cluster consists of two types of resources:The Control Plane coordinates the clusterNodes are the workers that run applicationsCluster DiagramThe Control Plane is responsible for managing the cluster. The Control Plane coordinates all activities in your cluster, such as scheduling applications, maintaining applications' desired state, scaling applications, and rolling out new updates.Control Planes manage the cluster and the nodes that are used to host the running applications.A node is a VM or a physical computer that serves as a worker machine in a Kubernetes cluster. Each node has a Kubelet, which is an agent for managing the node and communicating with the Kubernetes control plane. The node should also have tools for handling container operations, such as containerd or CRI-O. A Kubernetes cluster that handles production traffic should have a minimum of three nodes because if one node goes down, both an etcd member and a control plane instance are lost, and redundancy is compromised. You can mitigate this risk by adding more control plane nodes.When you deploy applications on Kubernetes, you tell the control plane to start the application containers. The control plane schedules the containers to run on the cluster's nodes. Node-level components, such as the kubelet, communicate with the control plane using the Kubernetes API, which the control plane exposes. End users can also use the Kubernetes API directly to interact with the cluster.A Kubernetes cluster can be deployed on either physical or virtual machines. To get started with Kubernetes development, you can use Minikube. Minikube is a lightweight Kubernetes implementation that creates a VM on your local machine and deploys a simple cluster containing only one node. Minikube is available for Linux, macOS, and Windows systems. The Minikube CLI provides basi


Question: How does Using Minikube to Create a Cluster work?

Answer: Using Minikube to Create a ClusterObjectivesLearn what a Kubernetes cluster is.Learn what Minikube is.Start a Kubernetes cluster on your computer.Kubernetes ClustersKubernetes is a production-grade, open-source platform that orchestrates the placement (scheduling) and execution of application containers within and across computer clusters.Kubernetes coordinates a highly available cluster of computers that are connected to work as a single unit. The abstractions in Kubernetes allow you to deploy containerized applications to a cluster without tying them specifically to individual machines. To make use of this new model of deployment, applications need to be packaged in a way that decouples them from individual hosts: they need to be containerized. Containerized applications are more flexible and available than in past deployment models, where applications were installed directly onto specific machines as packages deeply integrated into the host. Kubernetes automates the distribution and scheduling of application containers across a cluster in a more efficient way. Kubernetes is an open-source platform and is production-ready.A Kubernetes cluster consists of two types of resources:The Control Plane coordinates the clusterNodes are the workers that run applicationsCluster DiagramThe Control Plane is responsible for managing the cluster. The Control Plane coordinates all activities in your cluster, such as scheduling applications, maintaining applications' desired state, scaling applications, and rolling out new updates.Control Planes manage the cluster and the nodes that are used to host the running applications.A node is a VM or a physical computer that serves as a worker machine in a Kubernetes cluster. Each node has a Kubelet, which is an agent for managing the node and communicating with the Kubernetes control plane. The node should also have tools for handling container operations, such as containerd or CRI-O. A Kubernetes cluster that handles production traffic should have a minimum of three nodes because if one node goes down, both an etcd member and a control plane instance are lost, and redundancy is compromised. You can mitigate this risk by adding more control plane nodes.When you deploy applications on Kubernetes, you tell the control plane to start the application containers. The control plane schedules the containers to run on the cluster's nodes. Node-level components, such as the kubelet, communicate with the control plane using the Kubernetes API, which the control plane exposes. End users can also use the Kubernetes API directly to interact with the cluster.A Kubernetes cluster can be deployed on either physical or virtual machines. To get started with Kubernetes development, you can use Minikube. Minikube is a lightweight Kubernetes implementation that creates a VM on your local machine and deploys a simple cluster containing only one node. Minikube is available for Linux, macOS, and Windows systems. The Minikube CLI provides basi


Question: When would you use Using Minikube to Create a Cluster?

Answer: Using Minikube to Create a ClusterObjectivesLearn what a Kubernetes cluster is.Learn what Minikube is.Start a Kubernetes cluster on your computer.Kubernetes ClustersKubernetes is a production-grade, open-source platform that orchestrates the placement (scheduling) and execution of application containers within and across computer clusters.Kubernetes coordinates a highly available cluster of computers that are connected to work as a single unit. The abstractions in Kubernetes allow you to deploy containerized applications to a cluster without tying them specifically to individual machines. To make use of this new model of deployment, applications need to be packaged in a way that decouples them from individual hosts: they need to be containerized. Containerized applications are more flexible and available than in past deployment models, where applications were installed directly onto specific machines as packages deeply integrated into the host. Kubernetes automates the distribution and scheduling of application containers across a cluster in a more efficient way. Kubernetes is an open-source platform and is production-ready.A Kubernetes cluster consists of two types of resources:The Control Plane coordinates the clusterNodes are the workers that run applicationsCluster DiagramThe Control Plane is responsible for managing the cluster. The Control Plane coordinates all activities in your cluster, such as scheduling applications, maintaining applications' desired state, scaling applications, and rolling out new updates.Control Planes manage the cluster and the nodes that are used to host the running applications.A node is a VM or a physical computer that serves as a worker machine in a Kubernetes cluster. Each node has a Kubelet, which is an agent for managing the node and communicating with the Kubernetes control plane. The node should also have tools for handling container operations, such as containerd or CRI-O. A Kubernetes cluster that handles production traffic should have a minimum of three nodes because if one node goes down, both an etcd member and a control plane instance are lost, and redundancy is compromised. You can mitigate this risk by adding more control plane nodes.When you deploy applications on Kubernetes, you tell the control plane to start the application containers. The control plane schedules the containers to run on the cluster's nodes. Node-level components, such as the kubelet, communicate with the control plane using the Kubernetes API, which the control plane exposes. End users can also use the Kubernetes API directly to interact with the cluster.A Kubernetes cluster can be deployed on either physical or virtual machines. To get started with Kubernetes development, you can use Minikube. Minikube is a lightweight Kubernetes implementation that creates a VM on your local machine and deploys a simple cluster containing only one node. Minikube is available for Linux, macOS, and Windows systems. The Minikube CLI provides basi