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ConfigMap ​

创建 ConfigMap ​

From literal ​

bash
$ kubectl create configmap mysql-conf \
    --from-literal=host=mysql \
    --from-literal=port=3306

From file ​

bash
$ echo -n mysql | tee host
$ echo -n 3306 | tee port

$ kubectl create configmap mysql-conf \
    --from-file=host \
    --from-file=port

From directory ​

bash
$ echo -n mysql | tee conf/host
$ echo -n 3306 | tee conf/port

$ kubectl create configmap mysql-conf --from-file=conf/

From env file ​

bash
$ echo "host=mysql\nport=3306" | tee conf.env

$ kubectl create configmap mysql-conf --from-env-file=conf.env

From YAML ​

yaml
apiVersion: v1
kind: ConfigMap
metadata:
  name: mysql-conf
data:
  host: mysql
  port: "3306"
bash
$ kubectl create -f conf.yaml

使用 ConfigMap ​

作为环境变量 ​

可以使用 env 从 ConfigMap 中取出特定的值作为环境变量：

yaml
apiVersion: v1
kind: Pod
metadata:
  name: busybox
spec:
  containers:
  - name: busybox
    image: busybox:1.31.0
    command:
    - /bin/sh
    - -c
    - echo $MYSQL_HOST:$MYSQL_PORT
    env:
    - name: MYSQL_HOST
      valueFrom:
        configMapKeyRef:
          name: mysql-conf
          key: host
    - name: MYSQL_PORT
      valueFrom:
        configMapKeyRef:
          name: mysql-conf
          key: port
  restartPolicy: Never

也可以使用 envFrom 使用整个 ConfigMap 作为环境变量：

yaml
apiVersion: v1
kind: ConfigMap
metadata:
  name: mysql-conf
data:
  MYSQL_HOST: mysql
  MYSQL_PORT: "3306"

---

apiVersion: v1
kind: Pod
metadata:
  name: busybox
spec:
  containers:
  - name: busybox
    image: busybox:1.31.0
    command:
    - /bin/sh
    - -c
    - echo $MYSQL_HOST:$MYSQL_PORT
    envFrom:
    - configMapRef:
        name: mysql-conf
  restartPolicy: Never

作为 Volume ​

yaml
apiVersion: v1
kind: Pod
metadata:
  name: busybox
spec:
  containers:
  - name: busybox
    image: busybox:1.31.0
    command:
    - /bin/sh
    - -c
    - echo $(cat /app/config/mysql-host):$(cat /app/config/mysql-port)
    volumeMounts:
    - name: config
      mountPath: /app/config
      readOnly: true
  volumes:
  - name: config
    configMap:
      name: mysql-conf
      items:
      - key: host
        path: mysql-host
      - key: port
        path: mysql-port
  restartPolicy: Never

ConfigMap 作为 Volume 使用的时候，会覆盖掉 mountPath 目录下的其它文件。如果只是想创建出新的文件，而不会目录下的其它文件产生影响，可以使用 subPath：

yaml
apiVersion: v1
kind: Pod
metadata:
  name: busybox
spec:
  containers:
  - name: busybox
    image: busybox:1.31.0
    command:
    - /bin/sh
    - -c
    - ls /var; sleep 3000
    volumeMounts:
    - name: config
      mountPath: /var/mysql-host
      subPath: mysql-host
  volumes:
  - name: config
    configMap:
      name: mysql-conf
      items:
      - key: host
        path: mysql-host
      - key: port
        path: mysql-port
  restartPolicy: Never

如果 ConfigMap 的数据发生更新，相应的 Volume 内容也会跟着自动更新。需要注意的是，使用了 subPath 的 Volume 内容不会自动更新。

参考 ​

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