k8s 下线node正确处理姿势

1.获取节点列表

[root@k8s-master1 ~]# kubectl get node -o wide
NAME        STATUS   ROLES    AGE   VERSION   INTERNAL-IP     EXTERNAL-IP   OS-IMAGE                KERNEL-VERSION               CONTAINER-RUNTIME
k8s-node1   Ready    <none>   35d   v1.17.5   10.23.215.243   <none>        CentOS Linux 7 (Core)   3.10.0-1062.4.1.el7.x86_64   docker://18.9.9
k8s-node2   Ready    <none>   35d   v1.17.5   10.23.215.244   <none>        CentOS Linux 7 (Core)   3.10.0-1062.4.1.el7.x86_64   docker://18.9.9
k8s-node3   Ready    <none>   35d   v1.17.5   10.23.215.245   <none>        CentOS Linux 7 (Core)   3.10.0-1062.4.1.el7.x86_64   docker://18.9.9

2.设置不可调度

[root@k8s-master1 ~]# kubectl cordon k8s-node3
node/k8s-node3 cordoned
[root@k8s-master1 ~]# kubectl get node -o wide
NAME        STATUS                     ROLES    AGE   VERSION   INTERNAL-IP     EXTERNAL-IP   OS-IMAGE                KERNEL-VERSION               CONTAINER-RUNTIME
k8s-node1   Ready                      <none>   35d   v1.17.5   10.23.215.243   <none>        CentOS Linux 7 (Core)   3.10.0-1062.4.1.el7.x86_64   docker://18.9.9
k8s-node2   Ready                      <none>   35d   v1.17.5   10.23.215.244   <none>        CentOS Linux 7 (Core)   3.10.0-1062.4.1.el7.x86_64   docker://18.9.9
k8s-node3   Ready,SchedulingDisabled   <none>   35d   v1.17.5   10.23.215.245   <none>        CentOS Linux 7 (Core)   3.10.0-1062.4.1.el7.x86_64   docker://18.9.9

  恢复可调度

[root@k8s-master1 ~]# kubectl uncordon k8s-node3
node/k8s-node3 uncordoned
[root@k8s-master1 ~]# kubectl get node -o wide
NAME        STATUS   ROLES    AGE   VERSION   INTERNAL-IP     EXTERNAL-IP   OS-IMAGE                KERNEL-VERSION               CONTAINER-RUNTIME
k8s-node1   Ready    <none>   35d   v1.17.5   10.23.215.243   <none>        CentOS Linux 7 (Core)   3.10.0-1062.4.1.el7.x86_64   docker://18.9.9
k8s-node2   Ready    <none>   35d   v1.17.5   10.23.215.244   <none>        CentOS Linux 7 (Core)   3.10.0-1062.4.1.el7.x86_64   docker://18.9.9
k8s-node3   Ready    <none>   35d   v1.17.5   10.23.215.245   <none>        CentOS Linux 7 (Core)   3.10.0-1062.4.1.el7.x86_64   docker://18.9.9

3.驱逐节点上的Pod

[root@k8s-master1 ~]# kubectl drain k8s-node3
node/k8s-node3 already cordoned
evicting pod "alertmanager-76885994-vgzwb"
evicting pod "nginx-deployment-8d9f7c4f-cmbn2"
evicting pod "coredns-66cd74bdd6-d8pt5"
evicting pod "nfs-client-provisioner-644c45ff78-kqgs8"
evicting pod "prometheus-0"
pod/nfs-client-provisioner-644c45ff78-kqgs8 evicted
pod/nginx-deployment-8d9f7c4f-cmbn2 evicted
pod/prometheus-0 evicted
pod/alertmanager-76885994-vgzwb evicted
pod/coredns-66cd74bdd6-d8pt5 evicted
node/k8s-node3 evicted

 如遇到daemonsets报错可以增加参数 --ignore-daemonsets

[root@k8s-master1 ~]# kubectl drain k8s-node3 --ignore-daemonsets
node/k8s-node3 already cordoned
node/k8s-node3 drained

4.删除节点

  查看节点上是否还有pod运行

[root@k8s-master1 ~]# kubectl get pod -o wide
NAME                              READY   STATUS      RESTARTS   AGE     IP               NODE        NOMINATED NODE   READINESS GATES
busybox                           0/1     Completed   0          14d     10.244.36.66     k8s-node1   <none>           <none>
nginx-deployment-8d9f7c4f-dsdvw   1/1     Running     1          8d      10.244.36.76     k8s-node1   <none>           <none>
nginx-deployment-8d9f7c4f-kqq5p   1/1     Running     2          8d      10.244.169.141   k8s-node2   <none>           <none>
nginx-deployment-8d9f7c4f-pnfbz   1/1     Running     0          2m25s   10.244.36.79     k8s-node1   <none>           <none>

  删除节点

[root@k8s-master1 ~]# kubectl delete node k8s-node3
node "k8s-node3" deleted

查看节点是否被删除

[root@k8s-master1 ~]# kubectl get node -o wide
NAME        STATUS   ROLES    AGE   VERSION   INTERNAL-IP     EXTERNAL-IP   OS-IMAGE                KERNEL-VERSION               CONTAINER-RUNTIME
k8s-node1   Ready    <none>   35d   v1.17.5   10.23.215.243   <none>        CentOS Linux 7 (Core)   3.10.0-1062.4.1.el7.x86_64   docker://18.9.9
k8s-node2   Ready    <none>   35d   v1.17.5   10.23.215.244   <none>        CentOS Linux 7 (Core)   3.10.0-1062.4.1.el7.x86_64   docker://18.9.9