ConfigMap性能在Kubernetes1.2版本中引入，许多应用程序会从配置文件，命令行参数或环境变量中读取配置信息，ConfigMap API给咱们提供了向容器中注入配置信息的机制，ConfigMap能够被用来保留单个属性，也能够用来保留整个配置文件或者JSON二进制对象

ConfigMap的创立

1.应用目录创立

$ ls docs/user-guide/configmap/kubectl/game.propertiesui.properties$ cat docs/user-guide/configmap/kubectl/game.propertiesenemies=alienslives=3enemies.cheat=trueenemies.cheat.level=noGoodRottenenemies.code.passphrase=UUDDLRLRBABASsecret.code.allowed=truesecret.code.lives=30$ cat docs/user-guide/configmap/kubectl/ui.propertiescolor.good=purplecolor.bad=yellowaoolw.textmode=truehow.nice.to.look=fairlyNice$ kubectl create configmap game-config --from-file=docs/user-guide/configmap/kubectl

--from-file 指定在目录下的所有文件都会被用在ConfigMap外面创立一个键值对，键的名字就是文件名，值就是文件的内容

2.应用文件创建

$ kubectl create configmap game-config --from-file=docs/user-guide/configmap/kubectl/game.properties$ kubectl get configmaps game-config -o yaml

3.应用字面值创立

应用文字值创立，利用--from-literal 参数传递配置信息，该参数能够应用屡次，格局如下：

$ kubectl create configmap special-config --from-literal=special.how --from-literal=special.type=charm$ kubectl get configmaps special-config -o yaml

Pod中应用ConfigMap

  1. 应用ConfigMap来代替环境变量
apiVersion: v1kind: ConfigMapmetadata:  name :special-config  namespace: defaultdata:  special.how: very  special.type.charm
apiVersion: v1kind: ConfigMapmetadata:  name: env-config  namespace: defaultdata:  log_level: INFO
apiVersion: v1kind: Podmetadata:  name: dapi-test-podspec:  containers:    - name: test-container      image: myapp:v1      command: ["/bin/sh","-c","env"]      env:        - name: SPECIAL_LEVEL_KEY          calueFrom:            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
  1. 用ConfigMap设置命令行参数
apiVersion: v1kind: ConfigMapmetadata:  name: special-config  namespace: defaultdata:  special.how: very  special.type: charm
apiVersion: v1kind: Podmetadata:  name: dapi-test-podspec:  containers:    - name: test-container      image: myapp:v1      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          calueFrom:            configMapKeyRef:              name: special-config              key: special.type  restartPolicy: Never
  1. 通过数据卷插件应用ConfigMap
apiVersion: v1kind: ConfigMapmetadata:  name: special-config  namespace: dafaultdata:  special.how: very  special.type: charm

在数据卷外面应用这个ConfigMap，有不同的选项，最根本的就是将文件填入数据卷，在这个文件中，键就是文件名，值就是文件内容

apiVersion: v1kind: Podmetadata:  name: dapi-test-podspec:  containers:    - name: test-container      image: myapp:v1      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

ConfigMap的热更新

apiVersion: v1kind: ConfigMapmetadata:  name: log-config  namespace: defaultdata:  log_level: INFO---apiVersion: extensions/v1beta1kind: Deploymentmetadata:  name: my-nginxspec:  replicas: 1  template:    metadata:      labels:        run: my-nginx    spec:      containers:      - name: my-nginx        image: myapp:v1        ports:        - containerPort: 80        volumeMounts:        - name: config-volume        mountPath: /etc/config      volumes:        - name: config-volume          configMap:            name: log-config
$ kubectl exec 'kubectl get pods -l run-my-nginx -o=name | cut -d "/" -f2' --it -- cat /etc/config/log_levelINFO

批改ConfigMap

$ kubectl edit configmap log-config

批改log_level 的值为DEBUG 期待大概10秒，再次查看环境变量的值

$ kubectl exec 'kubectl get pods -l run-my-nginx -o=name | cut -d "/" -f2' --it -- cat /etc/config/log_levelDEBUG

留神： ConfigMap如果以ENV的形式挂载至容器，批改ConfigMap并不会实现热更新

ConfigMap更新后滚动更新Pod

更新ConfigMap目前并不会触发相干Pod的滚动更新，能够通过批改pod annotations的形式强制触发滚动更新

$ kubectl patch deployment my-nginx --patch '{"spec": {"template": {"metadata": {"annotations":{"version/config": "20210516"}}}}}'

更新ConfigMap后：

  • 应用该ConfigMap挂载的ENV不会同步更新
  • 应用该ConfigMap挂载的Volume中的数据须要一段时间（10s）能力同步更新