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