Kubernetes configmap 笔记

标签：configmap Kubernetes ConfigMap root master01 笔记 config special

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

从目录创建
从文件创建
从envfile创建
从 literal values 创建
...

使用ConfigMap

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=very
configmap/special-config created
[root@master01 ~]# kubectl get configmap
NAME               DATA   AGE
kube-root-ca.crt   1      42d
special-config     1      9s
[root@master01 ~]# kubectl describe configmap special-config
Name:         special-config
Namespace:    default
Labels:       <none>
Annotations:  <none>

Data
====
special.how:
----
very


Events:  <none>

创建Pod

[root@master01 configmap]# cat configmap.yaml 
apiVersion: v1
kind: 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-pod
Name:         dapi-test-pod
Namespace:    default
Priority:     0
Node:         node01/192.168.44.13
Start Time:   Tue, 06 Dec 2022 22:06:41 +0800
Labels:       <none>
Annotations:  <none>
Status:       Succeeded
IP:           172.29.55.34
IPs:
  IP:  172.29.55.34
Containers:
  test-container:
    Container ID:  docker://341fdf9b58e1254265de902d6fd5e23be205fb66353e400174b7abd869afc2e7
    Image:         busybox
    Image ID:      docker-pullable://busybox@sha256:59f225fdf34f28a07d22343ee415ee417f6b8365cf4a0d3a2933cbd8fd7cf8c1
    Port:          <none>
    Host Port:     <none>
    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:  <set to the key 'special.how' of config map 'special-config'>  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:    false
QoS Class:       BestEffort
Node-Selectors:  <none>
Tolerations:     node.kubernetes.io/not-ready:NoExecute op=Exists for 300s
                 node.kubernetes.io/unreachable:NoExecute op=Exists for 300s
Events:
  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

使用 yaml 创建 configmap

[root@master01 configmap]# cat config-mutikeys.yaml 
apiVersion: v1
kind: ConfigMap
metadata:
  name: special-config
  namespace: default
data:
  SPECIAL_LEVEL: very
  SPECIAL_TYPE: charm

[root@master01 configmap]# kubectl create -f config-mutikeys.yaml 
[root@master01 configmap]# kubectl get configmap
NAME               DATA   AGE
kube-root-ca.crt   1      42d
special-config     3      19m
[root@master01 configmap]# kubectl describe configmap special-config
Name:         special-config
Namespace:    default
Labels:       <none>
Annotations:  <none>

Data
====
SPECIAL_LEVEL:
----
very
SPECIAL_TYPE:
----
charm
Events:  <none>

创建Pod

[root@master01 configmap]# cat muti-keys-demo.yaml 
apiVersion: v1
kind: Pod
metadata:
  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: v1
kind: Pod
metadata:
  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   AGE
busybox                             1/1     Terminating   8          33d
config-map-demo                     1/1     Running       0          4s
nginx-deployment-5787596d54-42qfx   1/1     Running       0          50m
nginx-deployment-5787596d54-6ffh4   1/1     Terminating   3          28d
nginx-deployment-5787596d54-7m47n   1/1     Running       4          28d
nginx-deployment-5787596d54-cnjb8   1/1     Terminating   3          28d
nginx-deployment-5787596d54-d4lkw   1/1     Running       0          50m
[root@master01 configmap]# kubectl describe po config-map-demo
Name:         config-map-demo
Namespace:    default
Priority:     0
Node:         node01/192.168.44.13
Start Time:   Tue, 06 Dec 2022 22:38:37 +0800
Labels:       <none>
Annotations:  <none>
Status:       Running
IP:           172.29.55.39
IPs:
  IP:  172.29.55.39
Containers:
  test-config-map-1:
    Container ID:  docker://d6c068ee4c3d771c0ce73f3be41fcb8abffe17f56b968974ed579af5b007edfc
    Image:         busybox
    Image ID:      docker-pullable://busybox@sha256:59f225fdf34f28a07d22343ee415ee417f6b8365cf4a0d3a2933cbd8fd7cf8c1
    Port:          <none>
    Host Port:     <none>
    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:      <none>
    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:    false
QoS Class:       BestEffort
Node-Selectors:  <none>
Tolerations:     node.kubernetes.io/not-ready:NoExecute op=Exists for 300s
                 node.kubernetes.io/unreachable:NoExecute op=Exists for 300s
Events:
  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_LEVEL
very
/ # echo $very

/ # echo $SPECIAL_TYPE
charm

用存储在ConfigMap中的数据填充卷

[root@master01 configmap]# cat configmap-volume.yaml 
apiVersion: v1
kind: Pod
metadata:
  name: test-container-pod
spec:
  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   AGE
busybox                             1/1     Terminating   8          33d
nginx-deployment-5787596d54-42qfx   1/1     Running       0          63m
nginx-deployment-5787596d54-6ffh4   1/1     Terminating   3          28d
nginx-deployment-5787596d54-7m47n   1/1     Running       4          28d
nginx-deployment-5787596d54-cnjb8   1/1     Terminating   3          28d
nginx-deployment-5787596d54-d4lkw   1/1     Running       0          63m
test-container-pod                  1/1     Running       0          4s
[root@master01 configmap]# kubectl exec -ti test-container-pod -- sh 
/ # ls
bin   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 0
drwxrwxrwx    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_09.874549422
lrwxrwxrwx    1 root     root            31 Dec  6 14:51 ..data -> ..2022_12_06_14_51_09.874549422
lrwxrwxrwx    1 root     root            20 Dec  6 14:51 SPECIAL_LEVEL -> ..data/SPECIAL_LEVEL
lrwxrwxrwx    1 root     root            19 Dec  6 14:51 SPECIAL_TYPE -> ..data/SPECIAL_TYPE
lrwxrwxrwx    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

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。
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
```
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
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

标签：configmap,Kubernetes,ConfigMap,root,master01,笔记,config,special
From： https://www.cnblogs.com/arvinhuang/p/16961728.html