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Kubernetes外掛配置管理—ConfigMap介紹

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  其他容器編排排程工具會大談特談“輕應用”、“十二要素應用”,這樣就勢必會對企業級複雜應用做很大的改動。Kubernetes是為了解決“如何合理使用容器支撐企業級複雜應用”這個問題而誕生的,所以它的設計理念是要支援絕大多數應用的原生形態。例如,很多應用程式的配置需要通過配置檔案,命令列引數和環境變數的組合配置來完成(“十二要素應用”等均要求去配置)。這些配置應該從image內容中解耦,以此來保持容器化應用程式的可移植性。ConfigMap API資源提供了將配置資料注入容器的方式,同時保證該機制對容器來說是透明的。ConfigMap可以被用來儲存單個屬性,也可以用來儲存整個配置檔案或者JSON二進位制大物件。

  ConfigMap API資源儲存鍵/值對配置資料,這些資料可以在pods裡使用。ConfigMap跟Secrets類似,但是ConfigMap可以更方便的處理不包含敏感資訊的字串。示例如下:

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kind: ConfigMap
apiVersion: v1
metadata:
  creationTimestamp: 2016-02-18T19:14:38Z
  name: example-config
  namespace: default
data:
  example.property.1: hello
  example.property.2: world
  example.property.file: |-
    property.1=value-1
    property.2=value-2
    property.3=value-3
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  通過示例程式碼可以看到:ConfigMap可以包含細粒度的配置項,如:example.property.1;也可以包含粗粒度的配置檔案,如:example.property.file。

1、建立ConfigMap

1.1 從資料夾建立

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[[email protected] propertirs]# cat /home/yaml/propertirs/game.properties 
enemies=aliens
lives=3
enemies.cheat=true
enemies.cheat.level=noGoodRotten
secret.code.passphrase=UUDDLRLRBABAS
secret.code.allowed=true
secret.code.lives=30
[
[email protected]
propertirs]# cat /home/yaml/propertirs/ui.properties color.good=purple color.bad=yellow allow.textmode=true how.nice.to.look=fairlyNice [[email protected] propertirs]# kubectl create configmap game-config --from-file=/home/yaml/propertirs/ configmap "game-config" created [[email protected] propertirs]# kubectl describe configmaps game-config #該方法只能得到ConfigMap的Key和size Name: game-config Namespace: default Labels: <none> Annotations: <none> Data ==== ui.properties: 83 bytes game.properties: 158 bytes #若想得到詳細資訊,可通過以下命令: [[email protected] propertirs]# kubectl get configmaps game-config -o yaml apiVersion: v1 data: game.properties: | enemies=aliens lives=3 enemies.cheat=true enemies.cheat.level=noGoodRotten secret.code.passphrase=UUDDLRLRBABAS secret.code.allowed=true secret.code.lives=30 ui.properties: | color.good=purple color.bad=yellow allow.textmode=true how.nice.to.look=fairlyNice kind: ConfigMap metadata: creationTimestamp: 2017-03-21T03:22:34Z name: game-config namespace: default resourceVersion: "3002770" selfLink: /api/v1/namespaces/default/configmaps/game-config uid: a04f90f0-0de5-11e7-b3d5-fa163ebba51b
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1.2 從檔案建立

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[[email protected] propertirs]# kubectl create configmap game-config-2 --from-file=/home/yaml/propertirs/game.properties --from-file=/home/yaml/propertirs/ui.properties
configmap "game-config-2" created
[[email protected] propertirs]# kubectl get configmaps game-config-2 -o yaml
apiVersion: v1
data:
  game.properties: |
    enemies=aliens
    lives=3
    enemies.cheat=true
    enemies.cheat.level=noGoodRotten
    secret.code.passphrase=UUDDLRLRBABAS
    secret.code.allowed=true
    secret.code.lives=30
  ui.properties: |
    color.good=purple
    color.bad=yellow
    allow.textmode=true
    how.nice.to.look=fairlyNice
kind: ConfigMap
metadata:
  creationTimestamp: 2017-03-21T03:30:15Z
  name: game-config-2
  namespace: default
  resourceVersion: "3003415"
  selfLink: /api/v1/namespaces/default/configmaps/game-config-2
  uid: b2e4dfab-0de6-11e7-b3d5-fa163ebba51b
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1.3  指定data中的key

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[[email protected] propertirs]# kubectl create configmap game-config-3 --from-file=game-special-key=/home/yaml/propertirs/game.properties
configmap "game-config-3" created
[[email protected] propertirs]# kubectl get configmaps game-config-3 -o yaml
apiVersion: v1
data:
  game-special-key: |
    enemies=aliens
    lives=3
    enemies.cheat=true
    enemies.cheat.level=noGoodRotten
    secret.code.passphrase=UUDDLRLRBABAS
    secret.code.allowed=true
    secret.code.lives=30
kind: ConfigMap
metadata:
  creationTimestamp: 2017-03-21T03:33:23Z
  name: game-config-3
  namespace: default
  resourceVersion: "3003678"
  selfLink: /api/v1/namespaces/default/configmaps/game-config-3
  uid: 2345dad3-0de7-11e7-b3d5-fa163ebba51b
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1.4  指定具體的值

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[[email protected] propertirs]# kubectl create configmap game-config-4 --from-literal=special.user=zhenyu --from-literal=special.passwd=yaodidiao
configmap "game-config-4" created
[[email protected] propertirs]# kubectl get configmaps game-config-4 -o yaml
apiVersion: v1
data:
  special.passwd: yaodidiao
  special.user: zhenyu
kind: ConfigMap
metadata:
  creationTimestamp: 2017-03-21T03:36:12Z
  name: game-config-4
  namespace: default
  resourceVersion: "3003915"
  selfLink: /api/v1/namespaces/default/configmaps/game-config-4
  uid: 8802f6d2-0de7-11e7-b3d5-fa163ebba51b
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2、使用ConfigMap

2.1 環境變數或引數

  建立一個Pod,並將一個已經建立好的ConfigMap作為環境變數,注入到Pod中。

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[[email protected] propertirs]# kubectl get configmaps game-config-4 -o yaml
apiVersion: v1
data:
  special.passwd: yaodidiao
  special.user: zhenyu
kind: ConfigMap
metadata:
  creationTimestamp: 2017-03-21T03:36:12Z
  name: game-config-4
  namespace: default
  resourceVersion: "3003915"
  selfLink: /api/v1/namespaces/default/configmaps/game-config-4
  uid: 8802f6d2-0de7-11e7-b3d5-fa163ebba51b
[[email protected] 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-4
              key: special.user
      command:
      - sleep
      - "360000"
[[email protected] propertirs]# kubectl create -f testEnv.yaml 
pod "testenv" created
[[email protected] propertirs]# kubectl exec -ti testenv sh
/ # echo $SPECIAL_USER
zhenyu
/ #
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2.2 掛載檔案資料卷

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[[email protected] propertirs]# kubectl get configmaps game-config -o yaml
apiVersion: v1
data:
  game.properties: |
    enemies=aliens
    lives=3
    enemies.cheat=true
    enemies.cheat.level=noGoodRotten
    secret.code.passphrase=UUDDLRLRBABAS
    secret.code.allowed=true
    secret.code.lives=30
  ui.properties: |
    color.good=purple
    color.bad=yellow
    allow.textmode=true
    how.nice.to.look=fairlyNice
kind: ConfigMap
metadata:
  creationTimestamp: 2017-03-21T03:22:34Z
  name: game-config
  namespace: default
  resourceVersion: "3002770"
  selfLink: /api/v1/namespaces/default/configmaps/game-config
  uid: a04f90f0-0de5-11e7-b3d5-fa163ebba51b
[[email protected] 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
      - "360000"
  volumes:
    - name: config-volume
      configMap:
        name: game-config
[[email protected] propertirs]# kubectl create -f testVolume.yaml 
pod "testvolume" created
[[email protected] propertirs]# kubectl exec -ti testvolume sh
/ # cd /etc/config/
/etc/config # ls
game.properties  ui.properties
/etc/config # cat game.properties 
enemies=aliens
lives=3
enemies.cheat=true
enemies.cheat.level=noGoodRotten
secret.code.passphrase=UUDDLRLRBABAS
secret.code.allowed=true
secret.code.lives=30
/etc/config # cat ui.properties 
color.good=purple
color.bad=yellow
allow.textmode=true
how.nice.to.look=fairlyNice
/etc/config #
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2.3 掛載資訊資料卷

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[[email protected] 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
      - "360000"
  volumes:
    - name: config-volume
      configMap:
        name: game-config-4
[[email protected] propertirs]# kubectl get  configmaps game-config-4 -o yaml
apiVersion: v1
data:
  special.passwd: yaodidiao
  special.user: zhenyuyaodidiao
kind: ConfigMap
metadata:
  creationTimestamp: 2017-03-21T06:29:29Z
  name: game-config-4
  namespace: default
  resourceVersion: "3018779"
  selfLink: /api/v1/namespaces/default/configmaps/game-config-4
  uid: bd086dca-0dff-11e7-b3d5-fa163ebba51b
[[email protected] propertirs]# kubectl create -f testVolume.yaml 
pod "testvolume" created
[[email protected] 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
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2.4 熱更新

  當ConfigMap以資料卷的形式掛載進Pod的時,這時更新ConfigMap(或刪掉重建ConfigMap),Pod內掛載的配置資訊會熱更新。這時可以增加一些監測配置檔案變更的指令碼,然後reload對應服務。

 

  其他容器編排排程工具會大談特談“輕應用”、“十二要素應用”,這樣就勢必會對企業級複雜應用做很大的改動。Kubernetes是為了解決“如何合理使用容器支撐企業級複雜應用”這個問題而誕生的,所以它的設計理念是要支援絕大多數應用的原生形態。例如,很多應用程式的配置需要通過配置檔案,命令列引數和環境變數的組合配置來完成(“十二要素應用”等均要求去配置)。這些配置應該從image內容中解耦,以此來保持容器化應用程式的可移植性。ConfigMap API資源提供了將配置資料注入容器的方式,同時保證該機制對容器來說是透明的。ConfigMap可以被用來儲存單個屬性,也可以用來儲存整個配置檔案或者JSON二進位制大物件。

  ConfigMap API資源儲存鍵/值對配置資料,這些資料可以在pods裡使用。ConfigMap跟Secrets類似,但是ConfigMap可以更方便的處理不包含敏感資訊的字串。示例如下:

複製程式碼
kind: ConfigMap
apiVersion: v1
metadata:
  creationTimestamp: 2016-02-18T19:14:38Z
  name: example-config
  namespace: default
data:
  example.property.1: hello
  example.property.2: world
  example.property.file: |-
    property.1=value-1
    property.2=value-2
    property.3=value-3
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  通過示例程式碼可以看到:ConfigMap可以包含細粒度的配置項,如:example.property.1;也可以包含粗粒度的配置檔案,如:example.property.file。

1、建立ConfigMap

1.1 從資料夾建立

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[[email protected] propertirs]# cat /home/yaml/propertirs/game.properties 
enemies=aliens
lives=3
enemies.cheat=true
enemies.cheat.level=noGoodRotten
secret.code.passphrase=UUDDLRLRBABAS
secret.code.allowed=true
secret.code.lives=30
[[email protected] propertirs]# cat /home/yaml/propertirs/ui.properties 
color.good=purple
color.bad=yellow
allow.textmode=true
how.nice.to.look=fairlyNice
[[email protected] propertirs]# kubectl create configmap game-config --from-file=/home/yaml/propertirs/
configmap "game-config" created
[[email protected] propertirs]# kubectl describe configmaps game-config  
#該方法只能得到ConfigMap的Key和size
Name:        game-config
Namespace:    default
Labels:        <none>
Annotations:    <none>

Data
====
ui.properties:        83 bytes
game.properties:    158 bytes
#若想得到詳細資訊,可通過以下命令:
[[email protected] propertirs]# kubectl get configmaps game-config -o yaml
apiVersion: v1
data:
  game.properties: |
    enemies=aliens
    lives=3
    enemies.cheat=true
    enemies.cheat.level=noGoodRotten
    secret.code.passphrase=UUDDLRLRBABAS
    secret.code.allowed=true
    secret.code.lives=30
  ui.properties: |
    color.good=purple
    color.bad=yellow
    allow.textmode=true
    how.nice.to.look=fairlyNice
kind: ConfigMap
metadata:
  creationTimestamp: 2017-03-21T03:22:34Z
  name: game-config
  namespace: default
  resourceVersion: "3002770"
  selfLink: /api/v1/namespaces/default/configmaps/game-config
  uid: a04f90f0-0de5-11e7-b3d5-fa163ebba51b
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1.2 從檔案建立

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[[email protected] propertirs]# kubectl create configmap game-config-2 --from-file=/home/yaml/propertirs/game.properties --from-file=/home/yaml/propertirs/ui.properties
configmap "game-config-2" created
[[email protected] propertirs]# kubectl get configmaps game-config-2 -o yaml
apiVersion: v1
data:
  game.properties: |
    enemies=aliens
    lives=3
    enemies.cheat=true
    enemies.cheat.level=noGoodRotten
    secret.code.passphrase=UUDDLRLRBABAS
    secret.code.allowed=true
    secret.code.lives=30
  ui.properties: |
    color.good=purple
    color.bad=yellow
    allow.textmode=true
    how.nice.to.look=fairlyNice
kind: ConfigMap
metadata:
  creationTimestamp: 2017-03-21T03:30:15Z
  name: game-config-2
  namespace: default
  resourceVersion: "3003415"
  selfLink: /api/v1/namespaces/default/configmaps/game-config-2
  uid: b2e4dfab-0de6-11e7-b3d5-fa163ebba51b
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1.3  指定data中的key

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[[email protected] propertirs]# kubectl create configmap game-config-3 --from-file=game-special-key=/home/yaml/propertirs/game.properties
configmap "game-config-3" created
[[email protected] propertirs]# kubectl get configmaps game-config-3 -o yaml
apiVersion: v1
data:
  game-special-key: |
    enemies=aliens
    lives=3
    enemies.cheat=true
    enemies.cheat.level=noGoodRotten
    secret.code.passphrase=UUDDLRLRBABAS
    secret.code.allowed=true
    secret.code.lives=30
kind: ConfigMap
metadata:
  creationTimestamp: 2017-03-21T03:33:23Z
  name: game-config-3
  namespace: default
  resourceVersion: "3003678"
  selfLink: /api/v1/namespaces/default/configmaps/game-config-3
  uid: 2345dad3-0de7-11e7-b3d5-fa163ebba51b
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1.4  指定具體的值

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[[email protected] propertirs]# kubectl create configmap game-config-4 --from-literal=special.user=zhenyu --from-literal=special.passwd=yaodidiao
configmap "game-config-4" created
[[email protected] propertirs]# kubectl get configmaps game-config-4 -o yaml
apiVersion: v1
data:
  special.passwd: yaodidiao
  special.user: zhenyu
kind: ConfigMap
metadata:
  creationTimestamp: 2017-03-21T03:36:12Z
  name: game-config-4
  namespace: default
  resourceVersion: "3003915"
  selfLink: /api/v1/namespaces/default/configmaps/game-config-4
  uid: 8802f6d2-0de7-11e7-b3d5-fa163ebba51b
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2、使用ConfigMap

2.1 環境變數或引數

  建立一個Pod,並將一個已經建立好的ConfigMap作為環境變數,注入到Pod中。

複製程式碼
[[email protected] propertirs]# kubectl get configmaps game-config-4 -o yaml
apiVersion: v1
data:
  special.passwd: yaodidiao
  special.user: zhenyu
kind: ConfigMap
metadata:
  creationTimestamp: 2017-03-21T03:36:12Z
  name: game-config-4
  namespace: default
  resourceVersion: "3003915"
  selfLink: /api/v1/namespaces/default/configmaps/game-config-4
  uid: 8802f6d2-0de7-11e7-b3d5-fa163ebba51b
[[email protected] 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-4
              key: special.user
      command:
      - sleep
      - "360000"
[[email protected] propertirs]# kubectl create -f testEnv.yaml 
pod "testenv" created
[[email protected] propertirs]# kubectl exec -ti testenv sh
/ # echo $SPECIAL_USER
zhenyu
/ #
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2.2 掛載檔案資料卷

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[[email protected] propertirs]# kubectl get configmaps game-config -o yaml
apiVersion: v1
data:
  game.properties: |
    enemies=aliens
    lives=3
    enemies.cheat=true
    enemies.cheat.level=noGoodRotten
    secret.code.passphrase=UUDDLRLRBABAS
    secret.code.allowed=true
    secret.code.lives=30
  ui.properties: |
    color.good=purple
    color.bad=yellow
    allow.textmode=true
    how.nice.to.look=fairlyNice
kind: ConfigMap
metadata:
  creationTimestamp: 2017-03-21T03:22:34Z
  name: game-config
  namespace: default
  resourceVersion: "3002770"
  selfLink: /api/v1/namespaces/default/configmaps/game-config
  uid: a04f90f0-0de5-11e7-b3d5-fa163ebba51b
[[email protected] 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
      - "360000"
  volumes:
    - name: config-volume
      configMap:
        name: game-config
[[email protected] propertirs]# kubectl create -f testVolume.yaml 
pod "testvolume" created
[[email protected] propertirs]# kubectl exec -ti testvolume sh
/ # cd /etc/config/
/etc/config # ls
game.properties  ui.properties
/etc/config # cat game.properties 
enemies=aliens
lives=3
enemies.cheat=true
enemies.cheat.level=noGoodRotten
secret.code.passphrase=UUDDLRLRBABAS
secret.code.allowed=true
secret.code.lives=30
/etc/config # cat ui.properties 
color.good=purple
color.bad=yellow
allow.textmode=true
how.nice.to.look=fairlyNice
/etc/config #
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2.3 掛載資訊資料卷

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[[email protected] 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
      - "360000"
  volumes:
    - name: config-volume
      configMap:
        name: game-config-4
[[email protected] propertirs]# kubectl get  configmaps game-config-4 -o yaml
apiVersion: v1
data:
  special.passwd: yaodidiao
  special.user: zhenyuyaodidiao
kind: ConfigMap
metadata:
  creationTimestamp: 2017-03-21T06:29:29Z
  name: game-config-4
  namespace: default
  resourceVersion: "3018779"
  selfLink: /api/v1/namespaces/default/configmaps/game-config-4
  uid: bd086dca-0dff-11e7-b3d5-fa163ebba51b
[[email protected] propertirs]# kubectl create -f testVolume.yaml 
pod "testvolume" created
[[email protected] 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
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2.4 熱更新

  當ConfigMap以資料卷的形式掛載進Pod的時,這時更新ConfigMap(或刪掉重建ConfigMap),Pod內掛載的配置資訊會熱更新。這時可以增加一些監測配置檔案變更的指令碼,然後reload對應服務。