1.题目

Create a Deployment named deploy-important with label id=very-important (the pods should also have this label) and 3 replicas in namespace dev. It should contain two containers, the first named container1 with image nginx and the second one named container2 with image kubernetes/pause.
There should be only ever one Pod of that Deployment running on one worker node. We have two worker nodes: cluster1-worker1 and cluster1-worker2. Because the Deployment has three replicas the result should be that on both nodes one Pod is running. The third Pod won’t be scheduled, unless a new worker node will be added.

2.解析

本题目利用deployment来实现DaemonSet，考测pod affinity。

3.答案

1. 先创建deployment.yaml

   kubectl create deploy deploy-important -n dev --image=nginx \ 
   --dry-run=client -oyaml > 12.yaml

   编辑该yaml

   apiVersion: apps/v1
   kind: Deployment
   metadata:
   creationTimestamp: null
   labels:
    id: very-important                  # change
   name: deploy-important
   namespace: dev              
   spec:
   replicas: 3                           # change
   selector:
    matchLabels:
      id: very-important                # change
   strategy: {}
   template:
    metadata:
      creationTimestamp: null
      labels:
        id: very-important              # change
    spec:
      containers:
      - image: nginx:1.17.6-alpine
        name: container1                # change
        resources: {}
      - image: kubernetes/pause         # add
        name: container2                # add
      affinity:                                             # add
        podAntiAffinity:                                    # add
          requiredDuringSchedulingIgnoredDuringExecution:   # add
          - labelSelector:                                  # add
              matchExpressions:                             # add
              - key: id                                     # add
                operator: In                                # add
                values:                                     # add
                - very-important                            # add
            topologyKey: kubernetes.io/hostname             # add
   status: {}

   kubectl apply -f 12.yaml