[k8s]subpath解决cm覆盖目录问题

参考

发现cm老覆盖容器原有目录里的内容,后来不得不通过in -s的方式来搞cm, 先将cm挂到/tmp下,然后ln -s文件到指定目录.

后来发现个cm的subpath特性可以解决这个问题

写了busybox的cm和rc测试cm subpath

cat > busybox-cm.yaml <<EOF
apiVersion: v1
kind: ConfigMap
metadata:
  name: busybox-cm
  labels:
      addonmanager.kubernetes.io/mode: EnsureExists
data:
  Corefile: |
    .:53 {
        errors
        log stdout
        health
        kubernetes cluster.local 172.21.0.0/16
        prometheus
        proxy . /etc/resolv.conf
        cache 30
    }
EOF

cat > busybox.yaml <<EOF
apiVersion: v1
kind: ReplicationController
metadata:
  name: busybox-cm
  labels:
    app: busybox-cm
spec:
  replicas: 1
  selector:
    app: busybox-cm
  template:
    metadata:
      name: busybox-cm
      labels:
        app: busybox-cm
    spec:
      containers:
      - image: busybox
        command:
          - sleep
          - "3600"
        imagePullPolicy: IfNotPresent
        name: busybox
        volumeMounts:
        - name: config-volume
          mountPath: /usr/Corefile
          subPath: Corefile
      restartPolicy: Always
      volumes:
        - name: config-volume
          configMap:
            name: busybox-cm
            items:
            - key: Corefile
              path: Corefile
EOF