站长百科 Kubernetes外挂配置管理—ConfigMap介绍 正文

Kubernetes外挂配置管理—ConfigMap介绍

2022-12-03,,,,

目录贴：Kubernetes学习系列

　　其他容器编排调度工具会大谈特谈“轻应用”、“十二要素应用”，这样就势必会对企业级复杂应用做很大的改动。Kubernetes是为了解决“如何合理使用容器支撑企业级复杂应用”这个问题而诞生的，所以它的设计理念是要支持绝大多数应用的原生形态。例如，很多应用程序的配置需要通过配置文件，命令行参数和环境变量的组合配置来完成（“十二要素应用”等均要求去配置）。这些配置应该从image内容中解耦，以此来保持容器化应用程序的可移植性。ConfigMap API资源提供了将配置数据注入容器的方式，同时保证该机制对容器来说是透明的。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二进制大对象。

　　ConfigMap API资源存储键/值对配置数据，这些数据可以在pods里使用。ConfigMap跟Secrets类似，但是ConfigMap可以更方便的处理不包含敏感信息的字符串。示例如下：

kind: ConfigMap

apiVersion: v1

metadata:

  creationTimestamp: --18T19::38Z

  name: example-config

  namespace: default

data:

  example.property.: hello

  example.property.: world

  example.property.file: |-

    property.=value-

    property.=value-

    property.=value-

　　通过示例代码可以看到：ConfigMap可以包含细粒度的配置项，如：example.property.1；也可以包含粗粒度的配置文件，如：example.property.file。

1、创建ConfigMap

1.1 从文件夹创建

[root@k8s-master propertirs]# cat /home/yaml/propertirs/game.properties

enemies=aliens

lives=

enemies.cheat=true

enemies.cheat.level=noGoodRotten

secret.code.passphrase=UUDDLRLRBABAS

secret.code.allowed=true

secret.code.lives=

[root@k8s-master propertirs]# cat /home/yaml/propertirs/ui.properties

color.good=purple

color.bad=yellow

allow.textmode=true

how.nice.to.look=fairlyNice

[root@k8s-master propertirs]# kubectl create configmap game-config --from-file=/home/yaml/propertirs/

configmap "game-config" created

[root@k8s-master propertirs]# kubectl describe configmaps game-config

#该方法只能得到ConfigMap的Key和size

Name:        game-config

Namespace:    default

Labels:        <none>

Annotations:    <none>

Data

====

ui.properties:         bytes

game.properties:     bytes

#若想得到详细信息，可通过以下命令：

[root@k8s-master propertirs]# kubectl get configmaps game-config -o yaml

apiVersion: v1

data:

  game.properties: |

    enemies=aliens

    lives=

    enemies.cheat=true

    enemies.cheat.level=noGoodRotten

    secret.code.passphrase=UUDDLRLRBABAS

    secret.code.allowed=true

    secret.code.lives=

  ui.properties: |

    color.good=purple

    color.bad=yellow

    allow.textmode=true

    how.nice.to.look=fairlyNice

kind: ConfigMap

metadata:

  creationTimestamp: --21T03::34Z

  name: game-config

  namespace: default

  resourceVersion: ""

  selfLink: /api/v1/namespaces/default/configmaps/game-config

  uid: a04f90f0-0de5-11e7-b3d5-fa163ebba51b

1.2 从文件创建

[root@k8s-master propertirs]# kubectl create configmap game-config- --from-file=/home/yaml/propertirs/game.properties --from-file=/home/yaml/propertirs/ui.properties

configmap "game-config-2" created

[root@k8s-master propertirs]# kubectl get configmaps game-config- -o yaml

apiVersion: v1

data:

  game.properties: |

    enemies=aliens

    lives=

    enemies.cheat=true

    enemies.cheat.level=noGoodRotten

    secret.code.passphrase=UUDDLRLRBABAS

    secret.code.allowed=true

    secret.code.lives=

  ui.properties: |

    color.good=purple

    color.bad=yellow

    allow.textmode=true

    how.nice.to.look=fairlyNice

kind: ConfigMap

metadata:

  creationTimestamp: --21T03::15Z

  name: game-config-

  namespace: default

  resourceVersion: ""

  selfLink: /api/v1/namespaces/default/configmaps/game-config-

  uid: b2e4dfab-0de6-11e7-b3d5-fa163ebba51b

1.3  指定data中的key

[root@k8s-master propertirs]# kubectl create configmap game-config- --from-file=game-special-key=/home/yaml/propertirs/game.properties

configmap "game-config-3" created

[root@k8s-master propertirs]# kubectl get configmaps game-config- -o yaml

apiVersion: v1

data:

  game-special-key: |

    enemies=aliens

    lives=

    enemies.cheat=true

    enemies.cheat.level=noGoodRotten

    secret.code.passphrase=UUDDLRLRBABAS

    secret.code.allowed=true

    secret.code.lives=

kind: ConfigMap

metadata:

  creationTimestamp: --21T03::23Z

  name: game-config-

  namespace: default

  resourceVersion: ""

  selfLink: /api/v1/namespaces/default/configmaps/game-config-

  uid: 2345dad3-0de7-11e7-b3d5-fa163ebba51b

1.4  指定具体的值

[root@k8s-master propertirs]# kubectl create configmap game-config- --from-literal=special.user=zhenyu --from-literal=special.passwd=yaodidiao

configmap "game-config-4" created

[root@k8s-master propertirs]# kubectl get configmaps game-config- -o yaml

apiVersion: v1

data:

  special.passwd: yaodidiao

  special.user: zhenyu

kind: ConfigMap

metadata:

  creationTimestamp: --21T03::12Z

  name: game-config-

  namespace: default

  resourceVersion: ""

  selfLink: /api/v1/namespaces/default/configmaps/game-config-

  uid: 8802f6d2-0de7-11e7-b3d5-fa163ebba51b

2、使用ConfigMap

2.1 环境变量或参数

　　创建一个Pod，并将一个已经创建好的ConfigMap作为环境变量，注入到Pod中。

[root@k8s-master propertirs]# kubectl get configmaps game-config- -o yaml

apiVersion: v1

data:

  special.passwd: yaodidiao

  special.user: zhenyu

kind: ConfigMap

metadata:

  creationTimestamp: --21T03::12Z

  name: game-config-

  namespace: default

  resourceVersion: ""

  selfLink: /api/v1/namespaces/default/configmaps/game-config-

  uid: 8802f6d2-0de7-11e7-b3d5-fa163ebba51b

[root@k8s-master propertirs]# cat testEnv.yaml

apiVersion: v1

kind: Pod

metadata:

  labels:

    name: testenv

    role: master

  name: testenv

spec:

  containers:

    - name: testenv

      image: busybox

      imagePullPolicy: IfNotPresent

      env:

        - name: SPECIAL_USER

          valueFrom:

            configMapKeyRef:

              name: game-config-

              key: special.user

      command:

      - sleep

      - ""

[root@k8s-master propertirs]# kubectl create -f testEnv.yaml

pod "testenv" created

[root@k8s-master propertirs]# kubectl exec -ti testenv sh

/ # echo $SPECIAL_USER

zhenyu

/ #

2.2 挂载文件数据卷

[root@k8s-master propertirs]# kubectl get configmaps game-config -o yaml

apiVersion: v1

data:

  game.properties: |

    enemies=aliens

    lives=

    enemies.cheat=true

    enemies.cheat.level=noGoodRotten

    secret.code.passphrase=UUDDLRLRBABAS

    secret.code.allowed=true

    secret.code.lives=

  ui.properties: |

    color.good=purple

    color.bad=yellow

    allow.textmode=true

    how.nice.to.look=fairlyNice

kind: ConfigMap

metadata:

  creationTimestamp: --21T03::34Z

  name: game-config

  namespace: default

  resourceVersion: ""

  selfLink: /api/v1/namespaces/default/configmaps/game-config

  uid: a04f90f0-0de5-11e7-b3d5-fa163ebba51b

[root@k8s-master propertirs]# cat testVolume.yaml

apiVersion: v1

kind: Pod

metadata:

  labels:

    name: testvolume

    role: master

  name: testvolume

spec:

  containers:

    - name: testvolume

      image: busybox

      imagePullPolicy: IfNotPresent

      volumeMounts:

      - name: config-volume

        mountPath: /etc/config

      command:

      - sleep

      - ""

  volumes:

    - name: config-volume

      configMap:

        name: game-config

[root@k8s-master propertirs]# kubectl create -f testVolume.yaml

pod "testvolume" created

[root@k8s-master propertirs]# kubectl exec -ti testvolume sh

/ # cd /etc/config/

/etc/config # ls

game.properties  ui.properties

/etc/config # cat game.properties

enemies=aliens

lives=

enemies.cheat=true

enemies.cheat.level=noGoodRotten

secret.code.passphrase=UUDDLRLRBABAS

secret.code.allowed=true

secret.code.lives=

/etc/config # cat ui.properties

color.good=purple

color.bad=yellow

allow.textmode=true

how.nice.to.look=fairlyNice

/etc/config #

2.3 挂载信息数据卷

[root@k8s-master propertirs]# cat testVolume.yaml

apiVersion: v1

kind: Pod

metadata:

  labels:

    name: testvolume

    role: master

  name: testvolume

spec:

  containers:

    - name: testvolume

      image: busybox

      imagePullPolicy: IfNotPresent

      volumeMounts:

      - name: config-volume

        mountPath: /etc/config

      command:

      - sleep

      - ""

  volumes:

    - name: config-volume

      configMap:

        name: game-config-

[root@k8s-master propertirs]# kubectl get  configmaps game-config- -o yaml

apiVersion: v1

data:

  special.passwd: yaodidiao

  special.user: zhenyuyaodidiao

kind: ConfigMap

metadata:

  creationTimestamp: --21T06::29Z

  name: game-config-

  namespace: default

  resourceVersion: ""

  selfLink: /api/v1/namespaces/default/configmaps/game-config-

  uid: bd086dca-0dff-11e7-b3d5-fa163ebba51b

[root@k8s-master propertirs]# kubectl create -f testVolume.yaml

pod "testvolume" created

[root@k8s-master propertirs]# kubectl exec -ti testvolume sh

/ # cd /etc/config/

/etc/config # ls

special.passwd  special.user

/etc/config # cat special.user

zhenyuyaodidiao/etc/config #

/etc/config # exit

2.4 热更新

　　当ConfigMap以数据卷的形式挂载进Pod的时，这时更新ConfigMap（或删掉重建ConfigMap），Pod内挂载的配置信息会热更新。这时可以增加一些监测配置文件变更的脚本，然后reload对应服务。

Kubernetes外挂配置管理—ConfigMap介绍的相关教程结束。

《Kubernetes外挂配置管理—ConfigMap介绍.doc》

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