Kubernetes基础：命令行方式进行标签的管理

深藏阁楼爱情的钟 2023-07-04 11:15 4阅读 0赞

前面的文章中介绍过Kubernetes下标签的基本概念和使用方法，标签不但可以配置在YAML文件中在初始的状态生成，还可以动态的进行管理，这篇文章继续介绍如何使用kubectl label命令对标签进行管理。

# 使用标签 #

在Kubernetes中，可以对所有的资源进行标签的设定，同一个资源可以设定不同的标签，不同的资源也可以设定为相同标签，由于标签是键值对的数据形式，键是不能重复的。

# 环境准备 #

本文使用Kubernetes 1.17.2，可参看下文进行快速环境搭建：

*  [单机版本或者集群版本环境搭建][Link 1]

[root@host131 ansible]# kubectl get node -o wide
    NAME              STATUS   ROLES    AGE   VERSION   INTERNAL-IP       EXTERNAL-IP   OS-IMAGE                KERNEL-VERSION          CONTAINER-RUNTIME
    192.168.163.131   Ready    <none>   71s   v1.17.2   192.168.163.131   <none>        CentOS Linux 7 (Core)   3.10.0-957.el7.x86_64   docker://19.3.5
    [root@host131 ansible]#

# 示例准备 #

*  YAML文件示例

[root@host131 Pod]# cat single-pod.yaml 
    ---
    apiVersion: v1
    kind: Pod
    metadata:
      name: single-pod
    spec:
      containers:
      - name: blue-busybox-container
        image: busybox:1.31.1
        command: ["sleep"]
        args: ["1000"]
    ...
    [root@host131 Pod]#

*  创建Pod

[root@host131 Pod]# kubectl create -f single-pod.yaml 
    pod/single-pod created
    [root@host131 Pod]# 
    [root@host131 Pod]# kubectl get pods -o wide
    NAME         READY   STATUS    RESTARTS   AGE   IP             NODE              NOMINATED NODE   READINESS GATES
    single-pod   1/1     Running   0          6s    10.254.176.3   192.168.163.131   <none>           <none>
    [root@host131 Pod]#

*  查看标签

[root@host131 Pod]# kubectl describe pods single-pod |grep '^Labels'
    Labels:       <none>
    [root@host131 Pod]#

# 标签操作：添加标签 #

上述刚刚创建的Pod是没有Label设定的，给上述Pod添加app=testbox的标签

[root@host131 Pod]# kubectl label pod single-pod app=testbox
    pod/single-pod labeled
    [root@host131 Pod]#

# 标签操作：查询标签 #

可以使用describe结合grep确认标签

[root@host131 Pod]# kubectl describe pods single-pod |grep '^Labels'
    Labels:       app=testbox
    [root@host131 Pod]#

也可以直接在get pod命令后添加show-labels选项

[root@host131 Pod]# kubectl get pods --show-labels
    NAME         READY   STATUS    RESTARTS   AGE   LABELS
    single-pod   1/1     Running   0          65s   app=testbox
    [root@host131 Pod]#

# 标签操作：修改标签 #

label命令缺省有个overwrite选项，设定值为false，当指定其值为true时就可以进行修改标签，否则则会提示如下错误信息

[root@host131 Pod]# kubectl describe pods single-pod |grep '^Labels'
    Labels:       app=testbox
    [root@host131 Pod]# 
    [root@host131 Pod]# kubectl label pod single-pod app=single-pod
    error: 'app' already has a value (testbox), and --overwrite is false
    [root@host131 Pod]#

设定overwrite为true，即可进行修改

[root@host131 Pod]# kubectl label pod single-pod app=single-pod --overwrite
    pod/single-pod labeled
    [root@host131 Pod]#

确认修改信息

[root@host131 Pod]# kubectl describe pods single-pod |grep '^Labels'
    Labels:       app=single-pod
    [root@host131 Pod]# 
    [root@host131 Pod]# kubectl get pods --show-labels
    NAME         READY   STATUS    RESTARTS   AGE    LABELS
    single-pod   1/1     Running   0          114s   app=single-pod
    [root@host131 Pod]#

# 标签操作：添加多个标签 #

可以在上述标签基础之上，给此Pod再添加一个标签，同一资源可以有多个标签

[root@host131 Pod]# kubectl label pod single-pod environment=dev
    pod/single-pod labeled
    [root@host131 Pod]# kubectl get pods --show-labels
    NAME         READY   STATUS    RESTARTS   AGE     LABELS
    single-pod   1/1     Running   0          2m15s   app=single-pod,environment=dev
    [root@host131 Pod]#

# 标签操作：删除标签 #

[root@host131 Pod]# kubectl get pods --show-labels
    NAME         READY   STATUS    RESTARTS   AGE     LABELS
    single-pod   1/1     Running   0          2m15s   app=single-pod,environment=dev
    [root@host131 Pod]#

在标签后添加-，即可删除此标签，可参看如下执行示例

[root@host131 Pod]# kubectl label pod single-pod app-
    pod/single-pod labeled
    [root@host131 Pod]# kubectl get pods --show-labels
    NAME         READY   STATUS    RESTARTS   AGE     LABELS
    single-pod   1/1     Running   0          2m27s   environment=dev
    [root@host131 Pod]# kubectl label pod single-pod environment-
    pod/single-pod labeled
    [root@host131 Pod]# kubectl get pods --show-labels
    NAME         READY   STATUS    RESTARTS   AGE     LABELS
    single-pod   1/1     Running   0          2m37s   <none>
    [root@host131 Pod]# kubectl describe pods single-pod |grep '^Labels'
    Labels:       <none>
    [root@host131 Pod]#

[Link 1]: https://blog.csdn.net/liumiaocn/article/details/103725251