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ConfigMap功能在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给我们提供了向容器中注入配置信息的机制，ConfigMap可以被用来保存单个属性，也可以用来保存整个配置文件或者JSON二进制对象

ConfigMap的创建

1.使用目录创建

$ ls docs/user-guide/configmap/kubectl/ game.properties ui.properties $ cat docs/user-guide/configmap/kubectl/game.properties enemies=aliens lives=3 enemies.cheat=true enemies.cheat.level=noGoodRotten enemies.code.passphrase=UUDDLRLRBABAS secret.code.allowed=true secret.code.lives=30 $ cat docs/user-guide/configmap/kubectl/ui.properties color.good=purple color.bad=yellow aoolw.textmode=true how.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里面创建一个键值对，键的名字就是文件名，值就是文件的内容

2.使用文件创建

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

3.使用字面值创建

使用文字值创建，利用--from-literal 参数传递配置信息，该参数可以使用多次，格式如下：

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

Pod中使用ConfigMap

使用ConfigMap来替代环境变量 apiVersion: v1 kind: ConfigMap metadata: name :special-config namespace: default data: special.how: very special.type.charm apiVersion: v1 kind: ConfigMap metadata: name: env-config namespace: default data: log_level: INFO apiVersion: v1 kind: Pod metadata: name: dapi-test-pod spec: 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 用ConfigMap设置命令行参数 apiVersion: v1 kind: ConfigMap metadata: name: special-config namespace: default data: special.how: very special.type: charm apiVersion: v1 kind: Pod metadata: name: dapi-test-pod spec: 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 通过数据卷插件使用ConfigMap apiVersion: v1 kind: ConfigMap metadata: name: special-config namespace: dafault data: special.how: very special.type: charm

在数据卷里面使用这个ConfigMap，有不同的选项，最基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: v1 kind: Pod metadata: name: dapi-test-pod spec: 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: v1 kind: ConfigMap metadata: name: log-config namespace: default data: log_level: INFO --- apiVersion: extensions/v1beta1 kind: Deployment metadata: name: my-nginx spec: 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_level INFO

修改ConfigMap

$ kubectl edit configmap log-config

修改log_level 的值为DEBUG 等待大约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_level DEBUG

注意： ConfigMap如果以ENV的方式挂载至容器，修改ConfigMap并不会实现热更新

ConfigMap更新后滚动更新Pod

更新ConfigMap目前并不会触发相关Pod的滚动更新，可以通过修改pod annotations的方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：

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（10s）才能同步更新