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当前视点！Kubernetes configmap 笔记

来源：博客园

ConigMap

什么是ConfigMap

ConfigMap 采用 key-value 格式进行保存数据，一般用来保存非敏感数据，Pods可以将configmap作为环境变量、命令行参数或卷中的配置文件使用。ConfigMap 将特定环境的配置从容器中解耦。

创建ConfigMap

官方文档


(资料图片)

  1. 从目录创建

  2. 从文件创建

  3. 从envfile创建

  4. 从 literal values 创建

  5. ...

使用ConfigMap

  1. 以key-value为例

    创建 ConfigMap

kubectl create configmap special-config --from-literal=special.how=very
[root@master01 ~]# kubectl create configmap special-config --from-literal=special.how=veryconfigmap/special-config created[root@master01 ~]# kubectl get configmapNAME               DATA   AGEkube-root-ca.crt   1      42dspecial-config     1      9s[root@master01 ~]# kubectl describe configmap special-configName:         special-configNamespace:    defaultLabels:       Annotations:  Data====special.how:----veryEvents:

创建Pod

[root@master01 configmap]# cat configmap.yaml apiVersion: v1kind: Pod  metadata:   name: dapi-test-pod spec:  containers:    - name: test-container      image: 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

查看pod信息

[root@master01 configmap]# kubectl describe po dapi-test-podName:         dapi-test-podNamespace:    defaultPriority:     0Node:         node01/192.168.44.13Start Time:   Tue, 06 Dec 2022 22:06:41 +0800Labels:       Annotations:  Status:       SucceededIP:           172.29.55.34IPs:  IP:  172.29.55.34Containers:  test-container:    Container ID:  docker://341fdf9b58e1254265de902d6fd5e23be205fb66353e400174b7abd869afc2e7    Image:         busybox    Image ID:      docker-pullable://busybox@sha256:59f225fdf34f28a07d22343ee415ee417f6b8365cf4a0d3a2933cbd8fd7cf8c1    Port:              Host Port:         Command:      /bin/sh      -c      env    State:          Terminated      Reason:       Completed      Exit Code:    0      Started:      Tue, 06 Dec 2022 22:07:01 +0800      Finished:     Tue, 06 Dec 2022 22:07:01 +0800    Ready:          False    Restart Count:  0    Environment:      SPECIAL_LEVEL_KEY:    Optional: false    Mounts:      /var/run/secrets/kubernetes.io/serviceaccount from default-token-c7jnm (ro)Conditions:  Type              Status  Initialized       True   Ready             False   ContainersReady   False   PodScheduled      True Volumes:  default-token-c7jnm:    Type:        Secret (a volume populated by a Secret)    SecretName:  default-token-c7jnm    Optional:    falseQoS Class:       BestEffortNode-Selectors:  Tolerations:     node.kubernetes.io/not-ready:NoExecute op=Exists for 300s                 node.kubernetes.io/unreachable:NoExecute op=Exists for 300sEvents:  Type    Reason     Age    From               Message  ----    ------     ----   ----               -------  Normal  Scheduled  6m32s  default-scheduler  Successfully assigned default/dapi-test-pod to node01  Normal  Pulling    6m31s  kubelet            Pulling image "busybox"  Normal  Pulled     6m12s  kubelet            Successfully pulled image "busybox" in 18.272935062s  Normal  Created    6m12s  kubelet            Created container test-container  Normal  Started    6m12s  kubelet            Started container test-container
  1. 使用 yaml 创建 configmap
[root@master01 configmap]# cat config-mutikeys.yaml apiVersion: v1kind: ConfigMapmetadata:  name: special-config  namespace: defaultdata:  SPECIAL_LEVEL: very  SPECIAL_TYPE: charm
[root@master01 configmap]# kubectl create -f config-mutikeys.yaml [root@master01 configmap]# kubectl get configmapNAME               DATA   AGEkube-root-ca.crt   1      42dspecial-config     3      19m[root@master01 configmap]# kubectl describe configmap special-configName:         special-configNamespace:    defaultLabels:       Annotations:  Data====SPECIAL_LEVEL:----verySPECIAL_TYPE:----charmEvents:

创建Pod

[root@master01 configmap]# cat muti-keys-demo.yaml apiVersion: v1kind: Podmetadata:  name: config-map-demo spec:  containers:    - name: test-config-map-1      image: busybox      command:       - sleep       - "3600"      envFrom:      - configMapRef:          name: 
[root@master01 configmap]# cat muti-keys-demo.yaml apiVersion: v1kind: Podmetadata:  name: config-map-demo spec:  containers:    - name: test-config-map-1      image: busybox      command:       - sleep       - "3600"      envFrom:      - configMapRef:          name: special-config[root@master01 configmap]# kubectl create -f muti-keys-demo.yaml pod/config-map-demo created[root@master01 configmap]# kubectl get po NAME                                READY   STATUS        RESTARTS   AGEbusybox                             1/1     Terminating   8          33dconfig-map-demo                     1/1     Running       0          4snginx-deployment-5787596d54-42qfx   1/1     Running       0          50mnginx-deployment-5787596d54-6ffh4   1/1     Terminating   3          28dnginx-deployment-5787596d54-7m47n   1/1     Running       4          28dnginx-deployment-5787596d54-cnjb8   1/1     Terminating   3          28dnginx-deployment-5787596d54-d4lkw   1/1     Running       0          50m[root@master01 configmap]# kubectl describe po config-map-demoName:         config-map-demoNamespace:    defaultPriority:     0Node:         node01/192.168.44.13Start Time:   Tue, 06 Dec 2022 22:38:37 +0800Labels:       Annotations:  Status:       RunningIP:           172.29.55.39IPs:  IP:  172.29.55.39Containers:  test-config-map-1:    Container ID:  docker://d6c068ee4c3d771c0ce73f3be41fcb8abffe17f56b968974ed579af5b007edfc    Image:         busybox    Image ID:      docker-pullable://busybox@sha256:59f225fdf34f28a07d22343ee415ee417f6b8365cf4a0d3a2933cbd8fd7cf8c1    Port:              Host Port:         Command:      sleep      3600    State:          Running      Started:      Tue, 06 Dec 2022 22:38:40 +0800    Ready:          True    Restart Count:  0    Environment Variables from:      special-config  ConfigMap  Optional: false    Environment:          Mounts:      /var/run/secrets/kubernetes.io/serviceaccount from default-token-c7jnm (ro)Conditions:  Type              Status  Initialized       True   Ready             True   ContainersReady   True   PodScheduled      True Volumes:  default-token-c7jnm:    Type:        Secret (a volume populated by a Secret)    SecretName:  default-token-c7jnm    Optional:    falseQoS Class:       BestEffortNode-Selectors:  Tolerations:     node.kubernetes.io/not-ready:NoExecute op=Exists for 300s                 node.kubernetes.io/unreachable:NoExecute op=Exists for 300sEvents:  Type    Reason     Age   From               Message  ----    ------     ----  ----               -------  Normal  Scheduled  16s   default-scheduler  Successfully assigned default/config-map-demo to node01  Normal  Pulling    15s   kubelet            Pulling image "busybox"  Normal  Pulled     13s   kubelet            Successfully pulled image "busybox" in 1.951543384s  Normal  Created    13s   kubelet            Created container test-config-map-1  Normal  Started    13s   kubelet            Started container test-config-map-1
[root@master01 configmap]# kubectl exec -ti  config-map-demo  -- sh / # echo $SPECIAL_LEVELvery/ # echo $very/ # echo $SPECIAL_TYPEcharm

用存储在ConfigMap中的数据填充卷

[root@master01 configmap]# cat configmap-volume.yaml apiVersion: v1kind: Podmetadata:  name: test-container-podspec:  containers:    - name: test-container-1      image: busybox      command:       - sleep       - "3600"      volumeMounts:      - name: config-volume        mountPath: /etc/config #挂载到 /etc/config  volumes:    - name: config-volume      configMap:        name: special-config
[root@master01 configmap]# kubectl create -f configmap-volume.yaml pod/test-container-pod created[root@master01 configmap]# kubectl get po NAME                                READY   STATUS        RESTARTS   AGEbusybox                             1/1     Terminating   8          33dnginx-deployment-5787596d54-42qfx   1/1     Running       0          63mnginx-deployment-5787596d54-6ffh4   1/1     Terminating   3          28dnginx-deployment-5787596d54-7m47n   1/1     Running       4          28dnginx-deployment-5787596d54-cnjb8   1/1     Terminating   3          28dnginx-deployment-5787596d54-d4lkw   1/1     Running       0          63mtest-container-pod                  1/1     Running       0          4s[root@master01 configmap]# kubectl exec -ti test-container-pod -- sh / # lsbin   dev   etc   home  proc  root  sys   tmp   usr   var/ # ls /etc/config/      group        hostname     hosts        localtime    mtab         network/     passwd       resolv.conf  shadow/ # ls /etc/config/SPECIAL_LEVEL  SPECIAL_TYPE   special.how/ # ll /etc/config/sh: ll: not found/ # ls -al  /etc/config/total 0drwxrwxrwx    3 root     root           119 Dec  6 14:51 .drwxr-xr-x    1 root     root            20 Dec  6 14:51 ..drwxr-xr-x    2 root     root            66 Dec  6 14:51 ..2022_12_06_14_51_09.874549422lrwxrwxrwx    1 root     root            31 Dec  6 14:51 ..data -> ..2022_12_06_14_51_09.874549422lrwxrwxrwx    1 root     root            20 Dec  6 14:51 SPECIAL_LEVEL -> ..data/SPECIAL_LEVELlrwxrwxrwx    1 root     root            19 Dec  6 14:51 SPECIAL_TYPE -> ..data/SPECIAL_TYPElrwxrwxrwx    1 root     root            18 Dec  6 14:51 special.how -> ..data/special.how

If there are some files in the/etc/config/directory, they will be deleted.

注意事项

  1. 在 Pod 规约中引用某个ConfigMap之前，必须先创建这个对象， 或者在 Pod 规约中将 ConfigMap 标记为optional如果所引用的 ConfigMap 不存在，并且没有将应用标记为optional则 Pod 将无法启动。

  2. 如果你使用envFrom来基于 ConfigMap 定义环境变量，那么无效的键将被忽略。 Pod 可以被启动，但无效名称将被记录在事件日志中（InvalidVariableNames）

    kubectl get events

  3. 在 Pod 规约中将对 ConfigMap 的引用标记为可选（optional）。 如果 ConfigMap 不存在，那么它在 Pod 中为其提供数据的配置（例如环境变量、挂载的卷）将为空。 如果 ConfigMap 存在，但引用的键不存在，那么数据也是空的

  4. 当某个已被挂载的 ConfigMap 被更新，所对应得内容跟最终也会被更新。但是使用 ConfigMap 作为subPath 的数据卷不会更新

关键词： 环境变量 注意事项 配置文件