--- title: "ConfigMap 笔记" date: 2019-12-22T22:04:37+08:00 lastmod: 2019-12-22T22:04:37+08:00 tags: ["kubernetes", "configmap"] categories: ["container"] --- ## 概述 - ConfigMap 通常用于设置环境变量、设置命令行参数、创建配置文件 - Pod 使用 ConfigMap 前，ConfigMap 必须存在，否则 pod 不能启动 - ConfigMap 只能被在同一一个命名空间中的Pod所引用 ## 创建 ConfigMap - 命令如下 ```bash kubectl create configmap # 或者 kubectl apply -f ``` - map-name: ConfigMap 名称 - data-source: 目录、文件或具体值 ### 通过目录创建 ConfigMaps - 命令如下 ```bash kubectl create configmap game-config \ --from-file=https://k8s.io/docs/tasks/configure-pod-container/configmap/kubectl ``` - docs/tasks/configure-pod-container/configmap/kubectl/目录下的文件包括 ```bash ls docs/tasks/configure-pod-container/configmap/kubectl/ ``` - 输出如下 ``` game.properties ui.properties ``` - 查看 game-config 信息 ```bash kubectl describe configmaps game-config # 或者 kubectl get configmaps game-config -o yaml ``` ### 通过文件创建 ConfigMaps - 通过单个文件创建 ```bash kubectl create configmap game-config-2 \ --from-file=https://k8s.io/docs/tasks/configure-pod-container/configmap/kubectl/game.properties ``` - 通过多个文件创建 ```bash kubectl create configmap game-config-3 \ --from-file=https://k8s.io/docs/tasks/configure-pod-container/configmap/kubectl/game.properties \ --from-file=https://k8s.io/docs/tasks/configure-pod-container/configmap/kubectl/ui.properties ``` - 通过文件创建ConfigMap时可以定义文件的键 ```bash kubectl create configmap game-config-4 \ --from-file=game-special-key=https://k8s.io/docs/tasks/configure-pod-container/configmap/kubectl/game.properties # key 是 "game-special-key" # value 是 game.properties 文件的内容 ``` ### 通过具体值创建 ConfigMaps - 使用 --from-literal 参数定义具体值 ```bash kubectl create configmap special-config \ --from-literal=special.how=very \ --from-literal=special.type=charm ``` ## 使用 ConfigMap ### 定义 pod 环境变量 #### Pod 环境变量的值来自于单一 ConfigMap - 在ConfigMap中定义一个环境变量作为键值对 ```bash kubectl create configmap special-config --from-literal=special.how=very ``` - 指派ConfigMap中定义的special.how的值给Pod中SPECIAL_LEVEL_KEY环境变量 ```yaml apiVersion:v1 kind:Pod metadata: name:dapi-test-pod spec: containers: - name:test-container image:k8s.gcr.io/busybox command:["/bin/sh","-c","env"] env: # Define the environment variable - name:SPECIAL_LEVEL_KEY valueFrom: configMapKeyRef: # The ConfigMap containing the value you want to assign to SPECIAL_LEVEL_KEY name:special-config # Specify the key associated with the value key:special.how restartPolicy:Never ``` - 保存Pod规格的变化，Pod将输出SPECIAL_LEVEL_KEY=very #### Pod 环境变量的值来自于多个 ConfigMap - 创建两个 ConfigMap ```yaml --- apiVersion:v1 kind:ConfigMap metadata: name:special-config namespace:default data: special.how:very --- apiVersion:v1 kind:ConfigMap metadata: name:env-config namespace:default data: log_level:INFO ``` - 在Pod规格中定义环境变量 ```yaml apiVersion:v1 kind:Pod metadata: name:dapi-test-pod spec: containers: - name:test-container image:k8s.gcr.io/busybox command:["/bin/sh","-c","env"] env: - name:SPECIAL_LEVEL_KEY valueFrom: configMapKeyRef: name:special-config key:special.how - name:LOG_LEVEL valueFrom: configMapKeyRef: name:env-config key:log_level restartPolicy:Neverv ``` - 保存变更后的Pod，Pod将会输出SPECIAL_LEVEL_KEY=very和LOG_LEVEL=info ### 在一个ConfigMap中配置的键值对都作为一个Pod的环境变量 - **Kubernetes v1.6+可用** - 创建包含多个键-值对的ConfigMap ```yaml apiVersion:v1 kind:ConfigMap metadata: name:special-config namespace:default data: SPECIAL_LEVEL:very SPECIAL_TYPE:charm ``` - 使用envFrom定义所有的ConfigMap数据作为Pod的环境变量。来自于Config的键成为Pod中环境变量的名 ```yaml apiVersion:v1 kind:Pod metadata: name:dapi-test-pod spec: containers: - name:test-container image:k8s.gcr.io/busybox command:["/bin/sh","-c","env"] envFrom: - configMapRef: name:special-config restartPolicy:Never ``` - Pod的输出包括: SPECIAL_LEVEL=very 和 SPECIAL_TYPE=charm ### 在Pod命令行中使用ConfigMap定义的环境变量 - 在Pod规范的command 中使用$(VAR_NAME) ，获取ConfigMap定义的环境变量 ```yaml apiVersion:v1 kind:Pod metadata: name:dapi-test-pod spec: containers: - name:test-container image:k8s.gcr.io/busybox command:["/bin/sh","-c","echo $(SPECIAL_LEVEL_KEY) $(SPECIAL_TYPE_KEY)"] env: - name:SPECIAL_LEVEL_KEY valueFrom: configMapKeyRef: name:special-config key:SPECIAL_LEVEL - name:SPECIAL_TYPE_KEY valueFrom: configMapKeyRef: name:special-config key:SPECIAL_TYPE restartPolicy:Never ``` - test-container容器的输出: very charm ## 添加ConfigMap数据至存储卷 - 当通过–from-file创建的ConfigMap时，文件将作为一个键保存在ConfigMap中，而此文件的内容将作为值 ```bash apiVersion:v1 kind:ConfigMap metadata: name:special-config namespace:default data: special.level:very special.type:charm ``` ### 将ConfigMap中的数据传播到指定目录 - 在Pod的存储卷区域添加ConfigMap的名称 - 这将添加ConfigMap数据到volumeMounts.mountPath指定的目录下(此例为/etc/config) - command区域将引用保存在ConfigMap中的special.level条目 ```bash apiVersion:v1 kind:Pod metadata: name:dapi-test-pod spec: containers: - name:test-container image:k8s.gcr.io/busybox command:["/bin/sh","-c","ls /etc/config/"] volumeMounts: - name:config-volume mountPath:/etc/config volumes: - name:config-volume configMap: # Provide the name of the ConfigMap containing the files you want # to add to the container name:special-config restartPolicy:Never ``` - Pod运行时，command (“ls /etc/config/”)将输出: special.level special.type - **如果在/etc/config/目录下存在文件，将不会删除** ### 添加ConfigMap数据至存储卷指定的目录 - 为ConfigMap条目，使用path指定文件路径 - 此例中，special.level将在config-volume存储卷中被挂接至/etc/config/keys ```yaml apiVersion:v1 kind:Pod metadata: name:dapi-test-pod spec: containers: - name:test-container image:k8s.gcr.io/busybox command:["/bin/sh","-c","cat /etc/config/keys"] volumeMounts: - name:config-volume mountPath:/etc/config volumes: - name:config-volume configMap: name:special-config items: - key:special.level path:keys restartPolicy:Never ``` - Pod运行时，(“cat /etc/config/keys”) 将输出: very ## 参考 - [Kubernetes-配置字典ConfigMap](https://blog.csdn.net/bbwangj/article/details/81776648)