相关操作命令
# 查看节点
kubectl get nodes
# 设置节点为不可调度
kubectl cordon <NodeName>
# 设置节点为可调度
kubectl uncordon <NodeName>
# pod漂移到可调度的node节点上
kubectl drain <不可调度的node,上面有pod> --force --ignore-daemonsets
实际操作,把”cn-hangzhou.i-bp1bt6np98dbi2xmno0o,cn-hangzhou.i-bp1bt6np98dbi2xmno0p”设置为不可调度
# 查看node节点
kube-shell> kubectl get nodes
NAME STATUS ROLES AGE VERSION
cn-hangzhou.i-bp1bt6np98dbi2xmno0o Ready <none> 24d v1.12.6-aliyun.1
cn-hangzhou.i-bp1bt6np98dbi2xmno0p Ready <none> 24d v1.12.6-aliyun.1
cn-hangzhou.i-bp1cu5nvk55l2usiufx5 Ready <none> 35m v1.12.6-aliyun.1
kube-shell>
# 设置node节点为不可调度
kube-shell> kubectl cordon cn-hangzhou.i-bp1bt6np98dbi2xmno0o
node/cn-hangzhou.i-bp1bt6np98dbi2xmno0o cordoned
kube-shell> kubectl cordon cn-hangzhou.i-bp1bt6np98dbi2xmno0p
node/cn-hangzhou.i-bp1bt6np98dbi2xmno0p cordoned
kube-shell>
kubectl drain命令漂移不可调度node上的pod节点
# 查看修改调度后的node节点信息,其中2个node不可调度
kube-shell> kubectl get nodes
NAME STATUS ROLES AGE VERSION
cn-hangzhou.i-bp1bt6np98dbi2xmno0o Ready,SchedulingDisabled <none> 24d v1.12.6-aliyun.1
cn-hangzhou.i-bp1bt6np98dbi2xmno0p Ready,SchedulingDisabled <none> 24d v1.12.6-aliyun.1
cn-hangzhou.i-bp1cu5nvk55l2usiufx5 Ready <none> 37m v1.12.6-aliyun.1
kube-shell>
# 查看pod信息在那个node节点上
kube-shell> kubectl get pods -o wide
NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE
mynginx1-5dd8d4d78b-wgfjw 1/1 Running 0 15d 172.24.0.142 cn-hangzhou.i-bp1bt6np98dbi2xmno0o <none>
kube-shell>
# 把在node节点"cn-hangzhou.i-bp1bt6np98dbi2xmno0o"不可以node上的pod调度到可用的pod上
kube-shell> kubectl drain cn-hangzhou.i-bp1bt6np98dbi2xmno0o --force --ignore-daemonsets
node/cn-hangzhou.i-bp1bt6np98dbi2xmno0o already cordoned
WARNING: Ignoring DaemonSet-managed pods: node-exporter-v5knf, cattle-node-agent-rlb2d, flexvolume-25spk, kube-flannel-ds-6p557, kube-proxy-worker-fbdj8
pod/mynginx1-5dd8d4d78b-wgfjw evicted
pod/coredns-67fc48b9d7-f88lb evicted
pod/cattle-cluster-agent-57bd559c78-ck2mm evicted
pod/kube-state-metrics-b685fc8c4-tkzxt evicted
kube-shell>
验证
# 查看这个pod是不是已经漂移到可用的node上
kube-shell> kubectl get nodes
NAME STATUS ROLES AGE VERSION
cn-hangzhou.i-bp1bt6np98dbi2xmno0o Ready,SchedulingDisabled <none> 24d v1.12.6-aliyun.1
cn-hangzhou.i-bp1bt6np98dbi2xmno0p Ready,SchedulingDisabled <none> 24d v1.12.6-aliyun.1
cn-hangzhou.i-bp1cu5nvk55l2usiufx5 Ready <none> 55m v1.12.6-aliyun.1
kube-shell> kubectl get pods -o wide
NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE
mynginx1-5dd8d4d78b-wtdb8 1/1 Running 0 21m 172.24.1.3 cn-hangzhou.i-bp1cu5nvk55l2usiufx5 <none>
kube-shell>
参考文档
Safely Drain a Node while Respecting the PodDisruptionBudget - Kubernetes
https://kubernetes.io/docs/tasks/run-application/configure-pdb/
https://kubernetes.io/docs/reference/generated/kubectl/kubectl-commands#drain