ConfigMap 笔记

Sun, 22 Dec 2019 22:04:37 +0800

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

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kubectl create configmap <map-name> <data-source>
# 或者
kubectl apply -f <configmap-file.yml>

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

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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

`1`	`ls docs/tasks/configure-pod-container/configmap/kubectl/`

输出如下
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game.properties ui.properties

查看 game-config 信息

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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

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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

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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

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

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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

`1`	`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

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

---
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

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

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

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

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

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

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

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

Configmap on Colben Notes