configmap

字符串创建

$ kubectl create configmap special-config --from-literal=special.how=very --from-literal=special.type=charm
configmap "special-config" created
$ kubectl get configmap special-config -o go-template='{{.data}}'
map[special.how:very]
指定键为special.how值为very

目录创建

[root@k8s-master ~]# ls configmap/
game.properties  ui.properties
[root@k8s-master ~]# kubectl create configmap all --from-file=./configmap
[root@k8s-master ~]# kubectl describe cm all
Name:         all
Namespace:    default
Labels:       <none>
Annotations:  <none>

Data
====
game.properties:
----
enemies=aliens
#键为文件名称，值为文件内容

文件创建

apiVersion: v1
kind: ConfigMap
metadata:
  name: special-config
  namespace: default
data:
  special.how: very
  special.type: charm

作用：设置环境变量、设置容器命令行参数以及在 Volume 中直接挂载文件或目录。

设置环境变量

apiVersion: v1
kind: Pod
metadata:
  name: test-pod
spec:
  containers:
    - name: test-container
      image: gcr.io/google_containers/busybox
      command: ["/bin/sh", "-c", "env"]
      env:
        - name: SPECIAL_LEVEL_KEY #环境变量名称
          valueFrom:
            configMapKeyRef:
              name: special-config #cm名称
              key: special.how #引用cm的哪个键
        - name: SPECIAL_TYPE_KEY
          valueFrom:
            configMapKeyRef:
              name: special-config
              key: special.type
      envFrom:
        - configMapRef: 
            name: env-config #另一种设置环境变量的方式，调用这个cm里的值
  restartPolicy: Never

挂载

apiVersion: v1
kind: Pod
metadata:
  name: vol-test-pod
spec:
  containers:
    - name: test-container
      image: gcr.io/google_containers/busybox
      command: ["/bin/sh", "-c", "cat /etc/config/special.how"]
      volumeMounts:
      - name: config-volume
        mountPath: /etc/config/nginx.conf
        subPath: nginx.conf #只挂载单个文件
  volumes:
    - name: config-volume
      configMap:
        name: special-config
  restartPolicy: Never
#key值会做为文件名称，键为文件内容

将创建的 ConfigMap 中 special.how 这个 key 挂载到 / etc/config 目录下的一个相对路径 / keys/special.level。如果存在同名文件，直接覆盖。其他的 key 不挂载

apiVersion: v1
kind: Pod
metadata:
  name: dapi-test-pod
spec:
  containers:
    - name: test-container
      image: gcr.io/google_containers/busybox
      command: ["/bin/sh","-c","cat /etc/config/keys/special.level"]
      volumeMounts:
      - name: config-volume
        mountPath: /etc/config
        subPath: special.how #使用subpath对挂载的目录不覆盖
  volumes:
    - name: config-volume
      configMap:
        name: special-config
        items:
        - key: special.how
          path: keys/special.level
  restartPolicy: Never

更新 ConfigMap 后：使用该 ConfigMap 挂载的 Env 不会同步更新使用该 ConfigMap 挂载的 Volume 中的数据需要一段时间（实测大概10秒）才能同步更新