Kubernetes基础：给Pod加上Label

矫情吗；* 2023-07-03 10:58 28阅读 0赞

这篇文章以具体的例子来介绍如何在Pod实例上添加Label。

# 示例说明 #

比如如下在一个名为dev-pod的Pod上添加一个Label，Label的内容是：environment: dev

Pod生成并确认

[root@host131 Pod]# kubectl create -f pod-with-labels.yaml 
    pod/dev-pod created
    [root@host131 Pod]# kubectl get pods -o wide
    NAME      READY   STATUS    RESTARTS   AGE   IP             NODE              NOMINATED NODE   READINESS GATES
    dev-pod   1/1     Running   0          6s    10.254.152.5   192.168.163.131   <none>           <none>
    [root@host131 Pod]#

# 多个Pod #

给多个Pod都添加上environment的标签

[root@host131 Pod]# cat pod-with-labels.yaml 
    ---
    apiVersion: v1
    kind: Pod
    metadata:
      name: dev-pod
      namespace: default
      labels:
        environment: dev
    spec:
      containers:
      - name: dev-pod-host
        image: liumiaocn/tornado:latest
        command: ["python"]
        args: ["/usr/local/bin/daemon.py", "in dev environment"]
        ports:
            - containerPort: 80
    ...
    
    ---
    apiVersion: v1
    kind: Pod
    metadata:
      name: test-pod
      namespace: default
      labels:
        environment: test
    spec:
      containers:
      - name: test-pod-host
        image: liumiaocn/tornado:latest
        command: ["python"]
        args: ["/usr/local/bin/daemon.py", "in test environment"]
        ports:
            - containerPort: 80
    ...
    
    ---
    apiVersion: v1
    kind: Pod
    metadata:
      name: prod-pod
      namespace: default
      labels:
        environment: prod
    spec:
      containers:
      - name: prod-pod-host
        image: liumiaocn/tornado:latest
        command: ["python"]
        args: ["/usr/local/bin/daemon.py", "in prod environment"]
        ports:
            - containerPort: 80
    ...
    [root@host131 Pod]#

Pod生成与结果确认

[root@host131 Pod]# kubectl create -f pod-with-labels.yaml 
    pod/dev-pod created
    pod/test-pod created
    pod/prod-pod created
    [root@host131 Pod]# 
    [root@host131 Pod]# kubectl get pods -o wide
    NAME       READY   STATUS    RESTARTS   AGE   IP             NODE              NOMINATED NODE   READINESS GATES
    dev-pod    1/1     Running   0          7s    10.254.152.5   192.168.163.131   <none>           <none>
    prod-pod   1/1     Running   0          7s    10.254.152.7   192.168.163.131   <none>           <none>
    test-pod   1/1     Running   0          7s    10.254.152.6   192.168.163.131   <none>           <none>
    [root@host131 Pod]#

# kubectl命令中使用标签 #

使用-l或者--selector即可进行查询了

*  查询environment为dev的Pod信息

[root@host131 Pod]# kubectl get pods -l environment=dev -o wide
    NAME      READY   STATUS    RESTARTS   AGE     IP             NODE              NOMINATED NODE   READINESS GATES
    dev-pod   1/1     Running   0          4m43s   10.254.152.5   192.168.163.131   <none>           <none>
    [root@host131 Pod]#

*  查询environment为prod的Pod信息

[root@host131 Pod]# kubectl get pods --selector environment=prod -o wide
    NAME       READY   STATUS    RESTARTS   AGE     IP             NODE              NOMINATED NODE   READINESS GATES
    prod-pod   1/1     Running   0          5m14s   10.254.152.7   192.168.163.131   <none>           <none>
    [root@host131 Pod]#

*  查询environment为prod之外的Pod信息

[root@host131 Pod]# kubectl get pods -l environment!=prod -o wide
    NAME       READY   STATUS    RESTARTS   AGE    IP             NODE              NOMINATED NODE   READINESS GATES
    dev-pod    1/1     Running   0          6m9s   10.254.152.5   192.168.163.131   <none>           <none>
    test-pod   1/1     Running   0          6m9s   10.254.152.6   192.168.163.131   <none>           <none>
    [root@host131 Pod]#

# 修改Pod的Label #

比如事先又如下Pod

[root@host131 ReplicaSet]# kubectl get pods -o wide 
    NAME            READY   STATUS    RESTARTS   AGE     IP             NODE              NOMINATED NODE   READINESS GATES
    test-rs-7c27t   1/1     Running   0          6m55s   10.254.152.5   192.168.163.131   <none>           <none>
    [root@host131 ReplicaSet]#

此Pod的Label信息如下所示：

[root@host131 ReplicaSet]# kubectl describe pod test-rs-7c27t |grep Labels:
    Labels:       app=busybox-prod
    [root@host131 ReplicaSet]#

> 修改命令：kubectl label pod Pod名称 修改后的Label内容 --overwrite

执行示例和结果确认如下所示：

[root@host131 ReplicaSet]# kubectl label pod test-rs-7c27t app=busybox-dev --overwrite
    pod/test-rs-7c27t labeled
    [root@host131 ReplicaSet]# 
    [root@host131 ReplicaSet]# kubectl describe pod test-rs-7c27t |grep Labels:
    Labels:       app=busybox-dev
    [root@host131 ReplicaSet]#

# 总结 #

相同的Label可以添加在不同的资源上，同一资源可以设定多个Label，在使用时可以根据Lable进行资源选择，可以根据需要灵活使用。