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小册名称：Kubernets合辑5-Pod控制器

Node节点上污点管理

  1. 用法: 
  2.   增加污点: kubectl taint node <node_name> key=value:effect
  3.   取消污点: kubectl taint node <node_name> key=value:effect-
  4.   查看污点: kubectl describe node <node_name>
  5. effect:
  6.     PreferNoSchedule: 优先不调度，但是其它节点不满足时可以调度
  7.     NoSchedule: 禁止新的Pod调度，已经调度的Pod不会被驱逐
  8.   NoExecute: 禁止新的Pod调度，并且已经运行在该节点时的，其不能容忍污点的Pod将被驱逐
  1. # 查看master的污点
  2. [root@maxiaoke local-k8s-yaml]# kubectl describe node centos-7-51 
  3. Name:               centos-7-51
  4. Roles:              master
  5. Labels:             beta.kubernetes.io/arch=amd64
  6.                     beta.kubernetes.io/os=linux
  7.                     kubernetes.io/arch=amd64
  8.                     kubernetes.io/hostname=centos-7-51
  9.                     kubernetes.io/os=linux
  10.                     node-role.kubernetes.io/master=
  11. Annotations:        flannel.alpha.coreos.com/backend-data: {"VNI":1,"VtepMAC":"52:8a:0e:48:b4:92"}
  12.                     flannel.alpha.coreos.com/backend-type: vxlan
  13.                     flannel.alpha.coreos.com/kube-subnet-manager: true
  14.                     flannel.alpha.coreos.com/public-ip: 10.4.7.51
  15.                     kubeadm.alpha.kubernetes.io/cri-socket: /var/run/dockershim.sock
  16.                     node.alpha.kubernetes.io/ttl: 0
  17.                     volumes.kubernetes.io/controller-managed-attach-detach: true
  18. CreationTimestamp:  Fri, 04 Dec 2020 21:49:43 +0800
  19. Taints:             node-role.kubernetes.io/master:NoSchedule  # 不可调度
  20. ......
  1. # 以此作为示例Pod
  2. apiVersion: apps/v1
  3. kind: Deployment
  4. metadata:
  5.   name: nginx-deploy
  6. spec:
  7.   replicas: 6
  8.   selector:
  9.     matchLabels:
  10.       app: nginx
  11.   template:
  12.     metadata:
  13.       labels:
  14.         app: nginx
  15.     spec:
  16.       containers:
  17.       - name: nginx-demo
  18.         image: linuxmaxiaoke/nginx:v1.0.0
  1. # kubectl apply 部署上述的deployment后，Pod分散在三个不同的node上
  2. [root@maxiaoke local-k8s-yaml]# kubectl get pod -o wide
  3. NAME                            READY   STATUS    RESTARTS   AGE    IP             NODE          NOMINATED NODE   READINESS GATES
  4. nginx-deploy-8697d45cb8-4x564   1/1     Running   0          4m9s   172.16.4.9     centos-7-55   <none>           <none>
  5. nginx-deploy-8697d45cb8-bxms4   1/1     Running   0          4m9s   172.16.5.55    centos-7-56   <none>           <none>
  6. nginx-deploy-8697d45cb8-c4rbf   1/1     Running   0          4m9s   172.16.3.171   centos-7-54   <none>           <none>
  7. nginx-deploy-8697d45cb8-hvs92   1/1     Running   0          4m9s   172.16.3.172   centos-7-54   <none>           <none>
  8. nginx-deploy-8697d45cb8-sbfvj   1/1     Running   0          4m9s   172.16.5.54    centos-7-56   <none>           <none>
  9. nginx-deploy-8697d45cb8-sw5m4   1/1     Running   0          4m9s   172.16.4.10    centos-7-55   <none>           <none>
  1. # 使用NoSchedule污点，发现并不会使得现有的Pod发生重调度
  2. [root@maxiaoke local-k8s-yaml]# kubectl taint node centos-7-54 monitor=true:NoSchedule
  3. node/centos-7-54 tainted
  4. [root@maxiaoke local-k8s-yaml]# kubectl get pod -o wide
  5. NAME                            READY   STATUS    RESTARTS   AGE     IP             NODE          NOMINATED NODE   READINESS GATES
  6. nginx-deploy-8697d45cb8-4x564   1/1     Running   0          5m18s   172.16.4.9     centos-7-55   <none>           <none>
  7. nginx-deploy-8697d45cb8-bxms4   1/1     Running   0          5m18s   172.16.5.55    centos-7-56   <none>           <none>
  8. nginx-deploy-8697d45cb8-c4rbf   1/1     Running   0          5m18s   172.16.3.171   centos-7-54   <none>           <none>
  9. nginx-deploy-8697d45cb8-hvs92   1/1     Running   0          5m18s   172.16.3.172   centos-7-54   <none>           <none>
  10. nginx-deploy-8697d45cb8-sbfvj   1/1     Running   0          5m18s   172.16.5.54    centos-7-56   <none>           <none>
  11. nginx-deploy-8697d45cb8-sw5m4   1/1     Running   0          5m18s   172.16.4.10    centos-7-55   <none>           <none>
  13. # 更新deployment后，新的Pod不再调到 NoSchedule 节点
  14. root@maxiaoke local-k8s-yaml]# kubectl set image deployment nginx-deploy nginx-demo=linuxmaxiaoke/nginx:v1.0.1
  15. deployment.apps/nginx-deploy image updated
  16. [root@maxiaoke local-k8s-yaml]# kubectl get pod -o wide
  17. NAME                            READY   STATUS    RESTARTS   AGE   IP            NODE          NOMINATED NODE   READINESS GATES
  18. nginx-deploy-8494c5b6c5-5ddd9   1/1     Running   0          8s    172.16.4.13   centos-7-55   <none>           <none>
  19. nginx-deploy-8494c5b6c5-5zdjg   1/1     Running   0          10s   172.16.5.56   centos-7-56   <none>           <none>
  20. nginx-deploy-8494c5b6c5-bqpgn   1/1     Running   0          10s   172.16.5.57   centos-7-56   <none>           <none>
  21. nginx-deploy-8494c5b6c5-dq44w   1/1     Running   0          9s    172.16.4.12   centos-7-55   <none>           <none>
  22. nginx-deploy-8494c5b6c5-pnvw6   1/1     Running   0          8s    172.16.5.58   centos-7-56   <none>           <none>
  23. nginx-deploy-8494c5b6c5-xnf77   1/1     Running   0          10s   172.16.4.11   centos-7-55   <none>           <none>
  1. # 设置NoExecute后，现有Pod会被驱逐
  2. [root@maxiaoke local-k8s-yaml]# kubectl taint node centos-7-55 monitor=true:NoExecute
  3. node/centos-7-55 tainted
  4. [root@maxiaoke local-k8s-yaml]# kubectl get pod -o wide
  5. NAME                            READY   STATUS    RESTARTS   AGE    IP            NODE          NOMINATED NODE   READINESS GATES
  6. nginx-deploy-8494c5b6c5-5zdjg   1/1     Running   0          3m8s   172.16.5.56   centos-7-56   <none>           <none>
  7. nginx-deploy-8494c5b6c5-bqpgn   1/1     Running   0          3m8s   172.16.5.57   centos-7-56   <none>           <none>
  8. nginx-deploy-8494c5b6c5-bzc2c   1/1     Running   0          14s    172.16.5.60   centos-7-56   <none>           <none>
  9. nginx-deploy-8494c5b6c5-f7k2b   1/1     Running   0          14s    172.16.5.62   centos-7-56   <none>           <none>
  10. nginx-deploy-8494c5b6c5-pnvw6   1/1     Running   0          3m6s   172.16.5.58   centos-7-56   <none>           <none>
  11. nginx-deploy-8494c5b6c5-s57tv   1/1     Running   0          14s    172.16.5.61   centos-7-56   <none>           <none>

Pod的污点容忍度

  1. # api-server 能容忍所有NoExecute的污点，因此能在Master上运行
  2. [root@maxiaoke local-k8s-yaml]# kubectl describe pod -n kube-system kube-apiserver-centos-7-51  
  3. ......
  4. Tolerations:       :NoExecute
  1. # 清除所有节点的污点后，执行以下操作。模拟Prometheus(Prometheus占用内存巨大，推荐单独部署到一个固有节点)的部署
  2. [root@maxiaoke local-k8s-yaml]# kubectl label node centos-7-56 prometheus=true
  3. node/centos-7-56 labeled
  4. [root@maxiaoke local-k8s-yaml]# kubectl taint node centos-7-56 monitor=true:NoSchedule
  5. node/centos-7-56 tainted
  1. apiVersion: apps/v1
  2. kind: Deployment
  3. metadata:
  4.   name: prometheus
  5. spec:
  6.   replicas: 1
  7.   selector:
  8.     matchLabels:
  9.       app: prometheus
  10.   template:
  11.     metadata:
  12.       labels:
  13.         app: prometheus
  14.     spec:
  15.       containers:
  16.       - name: prometheus-demo
  17.         image: linuxmaxiaoke/nginx:v1.0.1
  18.       nodeSelector:
  19.         prometheus: "true"
  20.       tolerations:
  21.       - key: monitor
  22.         operator: Exists
  23.         effect: NoSchedule
  1. # 通过节点选择器和污点容忍度，实现独占一个节点
  2. [root@maxiaoke local-k8s-yaml]# kubectl get pod -o wide
  3. NAME                          READY   STATUS    RESTARTS   AGE     IP            NODE          NOMINATED NODE   READINESS GATES
  4. prometheus-76f64854b7-sxdq9   1/1     Running   0          2m21s   172.16.5.71   centos-7-56   <none>           <none>

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