Kubernetes中文文档

名词解释:ConfigMap

ConfigMap

ConfigMap用于保存配置数据的键值对,可以用来保存单个属性,也可以用来保存配置文件。ConfigMap跟secret很类似,但它可以更方便地处理不包含敏感信息的字符串。

ConfigMap创建

可以使用kubectl create configmap从文件、目录或者key-value字符串创建等创建ConfigMap。

# 从key-value字符串创建ConfigMap
$ kubectl create configmap special-config --from-literal=special.how=very
configmap "special-config" created
$ kubectl get configmap special-config -o go-template='{{.data}}'
map[special.how:very]

# 从env文件创建
$ echo -e "a=b\nc=d" | tee config.env
a=b
c=d
$ kubectl create configmap special-config --from-env-file=config.env
configmap "special-config" created
$ kubectl get configmap special-config -o go-template='{{.data}}'
map[a:b c:d]

# 从目录创建
$ mkdir config
$ echo a>config/a
$ echo b>config/b
$ kubectl create configmap special-config --from-file=config/
configmap "special-config" created
$ kubectl get configmap special-config -o go-template='{{.data}}'
map[a:a
 b:b
]

ConfigMap使用

ConfigMap可以通过多种方式在Pod中使用,比如设置环境变量、设置容器命令行参数、在Volume中创建配置文件等。

注意

  • ConfigMap必须在Pod引用它之前创建
  • 使用envFrom时,将会自动忽略无效的键
  • Pod只能使用同一个命名空间内的ConfigMap

用作环境变量

首先创建ConfigMap:

$ kubectl create configmap special-config --from-literal=special.how=very --from-literal=special.type=charm
$ kubectl create configmap env-config --from-literal=log_level=INFO

然后以环境变量方式引用

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
          valueFrom:
            configMapKeyRef:
              name: special-config
              key: special.how
        - name: SPECIAL_TYPE_KEY
          valueFrom:
            configMapKeyRef:
              name: special-config
              key: special.type
      envFrom:
        - configMapRef:
            name: env-config
  restartPolicy: Never

当pod运行结束后,它的输出会包括

SPECIAL_LEVEL_KEY=very
SPECIAL_TYPE_KEY=charm
log_level=INFO

用作命令行参数

将ConfigMap用作命令行参数时,需要先把ConfigMap的数据保存在环境变量中,然后通过$(VAR_NAME)的方式引用环境变量.

apiVersion: v1
kind: Pod
metadata:
  name: dapi-test-pod
spec:
  containers:
    - name: test-container
      image: gcr.io/google_containers/busybox
      command: [ "/bin/sh", "-c", "echo $(SPECIAL_LEVEL_KEY) $(SPECIAL_TYPE_KEY)" ]
      env:
        - name: SPECIAL_LEVEL_KEY
          valueFrom:
            configMapKeyRef:
              name: special-config
              key: special.how
        - name: SPECIAL_TYPE_KEY
          valueFrom:
            configMapKeyRef:
              name: special-config
              key: special.type
  restartPolicy: Never

当Pod结束后会输出

very charm

使用volume将ConfigMap作为文件或目录直接挂载

将创建的ConfigMap直接挂载至Pod的/etc/config目录下,其中每一个key-value键值对都会生成一个文件,key为文件名,value为内容

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
  volumes:
    - name: config-volume
      configMap:
        name: special-config
  restartPolicy: Never

当Pod结束后会输出

very

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
  volumes:
    - name: config-volume
      configMap:
        name: special-config
        items:
        - key: special.how
          path: keys/special.level
  restartPolicy: Never

当Pod结束后会输出

very

参考:https://feisky.gitbooks.io/kubernetes/concepts/configmap.html

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  1. #2

    先来个沙发再提问

    大牛哥7年前 (2017-07-26)
  2. #1

    创建configmap时怎么指定namespace

    大牛哥7年前 (2017-07-26)