【命令行工具kubectl】-编程知识

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如何在k8s的任意节点使用用kubectl

# 正常在node节点上是无法执行kubectl命令
[root@k8s-node-01 ~]# kubectl get pods
The connection to the server localhost:8080 was refused - did you specify the right host or port?

1、将master节点中/etc/kubernetes/,admin.conf拷贝到需要运行的node服务器的/etc/kubernetes目录中。

scp /etc/kubernetes/admin.conf root@k8s-node-01:/etc/kubernetes/admin.conf
scp /etc/kubernetes/admin.conf root@k8s-node-02:/etc/kubernetes/admin.conf

2、在对应的服务器上配置环境变量

echo " export KUBECONFIG=/etc/kubernetes/admin.conf " >> ~/.bash_profile
source ~/.bash_profile

# 执行上面的master第一步后，在node节点执行以下，就可以正常是用kubectl了
[root@k8s-node-01 ~]# echo " export KUBECONFIG=/etc/kubernetes/admin.conf " >> ~/.bash_profile
[root@k8s-node-01 ~]#   
[root@k8s-node-01 ~]#
[root@k8s-node-01 ~]# kubectl get pods
NAME                     READY   STATUS    RESTARTS      AGE
nginx-6768c68f7b-rsxb4   1/1     Running   1 (47m ago)   105m
nginx-test               1/1     Running   1 (47m ago)   70m

查看pod信息

[root@k8s-node-02 ~]#  kubectl get pod
NAME                     READY   STATUS    RESTARTS      AGE
nginx-6768c68f7b-rsxb4   1/1     Running   1 (62m ago)   120m
nginx-test               1/1     Running   1 (62m ago)   85m

下面这种执行方式是错误的，操作的是pod控制器，而非pod本身

[root@k8s-node-02 ~]# kubectl  scale   --replicas 3   nginx-6768c68f7b-rsxb4
error: the server doesn't have a resource type "nginx-6768c68f7b-rsxb4"

获取pod控制器信息

# 在创建nginx的时候指定了pod控制器版本是：deployment 
#[root@k8s-master ~]# kubectl create deployment   nginx  --image=nginx:1.20
# deployment.apps/nginx created# 在此处获取nginx这个pode的deploy控制器的版本时候就没有另外一个ningx-test这个信息
[root@k8s-node-02 ~]# kubectl get deploy
NAME    READY   UP-TO-DATE   AVAILABLE   AGE
nginx   1/1     1            1           120m

此处设置了deploy控制器是nginx的pod扩容为3个pod

[root@k8s-node-02 ~]# kubectl  scale deployment  --replicas 3   nginx
deployment.apps/nginx scaled# 此处可以查看到nginx这个deploy的数量是3
[root@k8s-node-02 ~]# kubectl get deploy
NAME    READY   UP-TO-DATE   AVAILABLE   AGE
nginx   3/3     3            3           10s# 同时可以到pod的信息，默认访问namespace是default
[root@k8s-node-02 ~]# kubectl get pod  -o wide 
NAME                     READY   STATUS    RESTARTS      AGE    IP          NODE          NOMINATED NODE   READINESS GATES
nginx-6768c68f7b-5m2zp   1/1     Running   0             10s    10.2.1.12   k8s-node-02   <none>           <none>
nginx-6768c68f7b-krdfm   1/1     Running   0             10s    10.2.2.8    k8s-node-01   <none>           <none>
nginx-6768c68f7b-rsxb4   1/1     Running   1 (64m ago)   123m   10.2.1.10   k8s-node-02   <none>           <none>
nginx-test               1/1     Running   1 (64m ago)   87m    10.2.1.11   k8s-node-02   <none>           <none>

获取到 deploy 的yaml信息，可以看到Replicas是3

[root@k8s-node-02 ~]# kubectl get deploy -o yaml
apiVersion: v1
items:
- apiVersion: apps/v1kind: Deploymentmetadata:annotations:deployment.kubernetes.io/revision: "1"creationTimestamp: "2024-02-22T09:30:58Z"generation: 2labels:app: nginxname: nginxnamespace: defaultresourceVersion: "187458"uid: 1515f10f-5072-4c8b-a9a5-1d04378a4b62spec:progressDeadlineSeconds: 600replicas: 3revisionHistoryLimit: 10selector:matchLabels:app: nginxstrategy:rollingUpdate:maxSurge: 25%maxUnavailable: 25%type: RollingUpdatetemplate:metadata:creationTimestamp: nulllabels:app: nginxspec:containers:- image: nginx:1.20imagePullPolicy: IfNotPresentname: nginxresources: {}terminationMessagePath: /dev/termination-logterminationMessagePolicy: FilednsPolicy: ClusterFirstrestartPolicy: AlwaysschedulerName: default-schedulersecurityContext: {}terminationGracePeriodSeconds: 30status:availableReplicas: 3conditions:- lastTransitionTime: "2024-02-22T09:30:58Z"lastUpdateTime: "2024-02-22T09:31:30Z"message: ReplicaSet "nginx-6768c68f7b" has successfully progressed.reason: NewReplicaSetAvailablestatus: "True"type: Progressing- lastTransitionTime: "2024-02-22T11:34:04Z"lastUpdateTime: "2024-02-22T11:34:04Z"message: Deployment has minimum availability.reason: MinimumReplicasAvailablestatus: "True"type: AvailableobservedGeneration: 2readyReplicas: 3replicas: 3updatedReplicas: 3
kind: List
metadata:resourceVersion: ""

修改这个deploy控制器是nginx的可以减少为1个

[root@k8s-node-02 ~]# kubectl  scale deployment  --replicas 1 nginx
deployment.apps/nginx scaled[root@k8s-node-02 ~]# kubectl get deploy -o yaml
apiVersion: v1
items:
- apiVersion: apps/v1kind: Deploymentmetadata:annotations:deployment.kubernetes.io/revision: "1"creationTimestamp: "2024-02-22T09:30:58Z"generation: 3labels:app: nginxname: nginxnamespace: defaultresourceVersion: "188540"uid: 1515f10f-5072-4c8b-a9a5-1d04378a4b62spec:progressDeadlineSeconds: 600replicas: 1revisionHistoryLimit: 10selector:matchLabels:app: nginxstrategy:rollingUpdate:maxSurge: 25%maxUnavailable: 25%type: RollingUpdatetemplate:metadata:creationTimestamp: nulllabels:app: nginxspec:containers:- image: nginx:1.20imagePullPolicy: IfNotPresentname: nginxresources: {}terminationMessagePath: /dev/termination-logterminationMessagePolicy: FilednsPolicy: ClusterFirstrestartPolicy: AlwaysschedulerName: default-schedulersecurityContext: {}terminationGracePeriodSeconds: 30status:availableReplicas: 1conditions:- lastTransitionTime: "2024-02-22T09:30:58Z"lastUpdateTime: "2024-02-22T09:31:30Z"message: ReplicaSet "nginx-6768c68f7b" has successfully progressed.reason: NewReplicaSetAvailablestatus: "True"type: Progressing- lastTransitionTime: "2024-02-22T11:34:04Z"lastUpdateTime: "2024-02-22T11:34:04Z"message: Deployment has minimum availability.reason: MinimumReplicasAvailablestatus: "True"type: AvailableobservedGeneration: 3readyReplicas: 1replicas: 1updatedReplicas: 1
kind: List
metadata:resourceVersion: ""