quality_of_service.md

Quality of Service

• We know that containers require resources to run the application.
• Those resources include
  • memory
  • cpu
• Below are the classes

Best Effort:

• The pods that doesnot specify requests and limits for there containers are consdered as lowest priority and most likely to be terminater first.
• This happens when the node is having shortage or resources

Burstable

• Pods that have requests and limits defined (limits should be greater than requests).
• Obviously, contianer is willing to consume more resources till the limit is reached.
• These pods have a minimal resource guarenty.
• When the nodes is short of resources, these pods are likely to be terminated when there are not best effort pods.

Guaranteed

• Pods that have equal amount of requests and limits.
• These are been considered as the highest priority pods and guaranteed not to be killed before best-effort and burstable pods.

Below is the example for Best Effort

apiVersion: v1
kind: Pod
metadata:
  name: best-effort-pod
spec: 
  containers: 
  - image: nginx
    name: nginx
    ports:
    - containerPort: 80
      protocol: TCP

Below is the example for Burstable

apiVersion: v1
kind: Pod
metadata:
  name: burstable-pod
spec: 
  containers: 
  - image: nginx
    name: nginx
    ports:
    - containerPort: 80
      protocol: TCP
    resources:
      requests:
        cpu: 100m
        memory: 100Mi
      limits:
        cpu: 200m
        memory: 200Mi

Below is the example for guarenteed

apiVersion: v1
kind: Pod
metadata:
  name: guarenty-pod
spec: 
  containers: 
  - image: nginx
    name: nginx
    ports:
    - containerPort: 80
      protocol: TCP
    resources:
      requests:
        cpu: 100m
        memory: 100Mi
      limits:
        cpu: 100m
        memory: 100Mi