Kubernetes基础：Replica Set之选择器

心已赠人 2023-07-03 12:11 15阅读 0赞

上篇文章介绍了RC选择器selector使用方式，这篇继续确认一下RS（Replica Set）的选择器的使用方法.

# RS的选择器使用示例：matchLabels #

RS的selector支持matchLabels和matchExpressions两种适配方式，matchLabels的使用方式中包含了和RC一样的使用方法，比如如下RS的YAML示例：

[root@host131 ReplicaSet]# cat selecotr-busybox-rs.yaml 
    ---
    apiVersion: apps/v1
    kind: ReplicaSet
    metadata:
      name: test-rs
    spec:
      replicas: 1
      selector:
        matchLabels:
          app: busybox-prod
      template:
        metadata:
          name: busybox
          labels:
            app: busybox-prod
        spec:
          containers:
          - name: busybox-host
            image: busybox:latest
            command: ["sleep"]
            args: ["100000"]
    ...
    [root@host131 ReplicaSet]#

结果确认

[root@host131 ReplicaSet]# kubectl create -f selecotr-busybox-rs.yaml 
    replicaset.apps/test-rs created
    [root@host131 ReplicaSet]# 
    [root@host131 ReplicaSet]# kubectl get rs -o wide
    NAME      DESIRED   CURRENT   READY   AGE   CONTAINERS     IMAGES           SELECTOR
    test-rs   1         1         1       7s    busybox-host   busybox:latest   app=busybox-prod
    [root@host131 ReplicaSet]# 
    [root@host131 ReplicaSet]# kubectl get pod -o wide
    NAME            READY   STATUS    RESTARTS   AGE   IP             NODE              NOMINATED NODE   READINESS GATES
    test-rs-lds5z   1/1     Running   0          13s   10.254.152.5   192.168.163.131   <none>           <none>
    [root@host131 ReplicaSet]#

可以看到在RC的信息中显示的SELECTOR为app=busybox-prod。

# RS的选择器使用示例：matchExpressions #

RS也可使用matchExpressions方式，比如如下RS的YAML示例：

[root@host131 ReplicaSet]# cat selecotr-busybox-rs.yaml 
    ---
    apiVersion: apps/v1
    kind: ReplicaSet
    metadata:
      name: test-rs
    spec:
      replicas: 1
      selector:
        matchExpressions:
          - key: app
            operator: In
            values:
              - busybox-prod
              - busybox-test
              - busybox-dev
      template:
        metadata:
          name: busybox
          labels:
            app: busybox-prod
        spec:
          containers:
          - name: busybox-host
            image: busybox:latest
            command: ["sleep"]
            args: ["100000"]
    ...
    [root@host131 ReplicaSet]#

结果确认

[root@host131 ReplicaSet]# kubectl create -f selecotr-busybox-rs.yaml 
    replicaset.apps/test-rs created
    [root@host131 ReplicaSet]# 
    [root@host131 ReplicaSet]# kubectl get rs -o wide
    NAME      DESIRED   CURRENT   READY   AGE   CONTAINERS     IMAGES           SELECTOR
    test-rs   1         1         0       6s    busybox-host   busybox:latest   app in (busybox-dev,busybox-prod,busybox-test)
    [root@host131 ReplicaSet]# 
    [root@host131 ReplicaSet]# kubectl get pod -o wide
    NAME            READY   STATUS    RESTARTS   AGE   IP             NODE              NOMINATED NODE   READINESS GATES
    test-rs-7c27t   1/1     Running   0          13s   10.254.152.5   192.168.163.131   <none>           <none>
    [root@host131 ReplicaSet]#

可以看到在RC的信息中显示的SELECTOR显示为app in (busybox-dev,busybox-prod,busybox-test)。可以使用集合方式的查询：

[root@host131 ReplicaSet]# kubectl get pod -o wide -l 'app in (busybox-dev,busybox-prod,busybox-test)'
    NAME            READY   STATUS    RESTARTS   AGE   IP             NODE              NOMINATED NODE   READINESS GATES
    test-rs-7c27t   1/1     Running   0          55s   10.254.152.5   192.168.163.131   <none>           <none>
    [root@host131 ReplicaSet]#