1 调度简介

在这里插入图片描述

[root@server2 ~]# kubectl get pod -n kube-system

在这里插入图片描述
在这里插入图片描述

2 影响kubernetes调度的因素

2.1 nodeName（针对节点）

[root@server2 ~]# vim pod.yaml
apiVersion: v1
kind: Pod
metadata:
  name: nginx
spec:
  containers:
  - name: nginx
    image: nginx
  nodeName: server3     指定节点调度到server3
[root@server2 ~]# kubectl apply -f pod.yaml   运行，pod直接被调度到server3上
[root@server2 ~]# vim pod.yaml  
apiVersion: v1
kind: Pod
metadata:
  name: nginx
spec:
  containers:
  - name: nginx
    image: nginx
  nodeName: server13    指定错误的节点
[root@server2 ~]# kubectl get pod   运行不成功
NAME    READY   STATUS    RESTARTS   AGE
nginx   0/1     Pending   0          12s
缺点：直接无视存在的节点，直奔指定的节点

2.2 nodeSelector（针对节点）

在这里插入图片描述

[root@server2 ~]# cat pod.yaml 
apiVersion: v1
kind: Pod
metadata:
  name: nginx
spec:
  containers:
  - name: nginx
    image: nginx
  nodeSelector:  
    disktype: ssd    标签
[root@server2 ~]# kubectl apply -f pod.yaml   创建
pod/nginx created
[root@server2 ~]# kubectl get pod  查看pod，没有运行成功，因为没有匹配的标签
NAME    READY   STATUS    RESTARTS   AGE
nginx   0/1     Pending   0          103s
[root@server2 ~]# kubectl label nodes server4 disktype=ssd  添加server4节点标签为disktype=ssd 
node/server4 labeled
[root@server2 ~]# kubectl get pod   查看pod，运行成功
NAME    READY   STATUS    RESTARTS   AGE
nginx   1/1     Running   0          5m19s
[root@server2 ~]# kubectl get node --show-labels  查看节点标签，标签已经添加

在这里插入图片描述

[root@server2 ~]# kubectl label nodes server4 disktype-   如果删除标签，-表示去掉
node/server4 unlabeled
[root@server2 ~]# kubectl get pod  查看pod还是运行成功，因为以及调度过去了
NAME    READY   STATUS    RESTARTS   AGE
nginx   1/1     Running   0          10m

2.3 亲和与反亲和（针对节点）

在这里插入图片描述
调度官方网址

[root@server2 ~]# kubectl delete -f pod.yaml    删除之前pod
pod "nginx" deleted
[root@server2 ~]# vim pod.yaml 
apiVersion: v1
kind: Pod
metadata:
  name: nginx
spec:
  containers:
  - name: nginx
    image: nginx
  affinity:
    nodeAffinity:   节点亲和性
      requiredDuringSchedulingIgnoredDuringExecution:   必须满足
           nodeSelectorTerms:    匹配标签
           - matchExpressions:
             - key: disktype   匹配 的key
               operator: In   运算符为in
               values:  取值
                 - ssd   匹配的取值为ssd
[root@server2 ~]# kubectl apply -f pod.yaml  创建
pod/nginx created 
[root@server2 ~]# kubectl get pod    查看pod
NAME    READY   STATUS    RESTARTS   AGE
nginx   0/1     Pending   0          19s
[root@server2 ~]# kubectl label nodes server3 disktype=ssd  给server3节点加标签
node/server3 labeled
[root@server2 ~]# kubectl get pod  查看pod，运行成功
NAME    READY   STATUS    RESTARTS   AGE
nginx   1/1     Running   0          2m57s 
 [root@server2 ~]#  kubectl label nodes server4 disktype=ssd   给server4节点加标签
node/server4 labeled

添加倾向满足

[root@server2 ~]# kubectl delete -f pod.yaml 
pod "nginx" deleted
[root@server2 ~]# vim pod.yaml  
apiVersion: v1
kind: Pod
metadata:
  name: nginx
spec:
  containers:
  - name: nginx
    image: nginx
  affinity:
    nodeAffinity:
      requiredDuringSchedulingIgnoredDuringExecution:
           nodeSelectorTerms:
           - matchExpressions:
             - key: disktype
               operator: In
               values:
                 - ssd
      preferredDuringSchedulingIgnoredDuringExecution:  添加倾向性
      - weight: 1  
        preference:
          matchExpressions:
          - key: kubernetes.io/hostname
            operator: In
            values:
            - server4    倾向server4

[root@server2 ~]# kubectl apply -f pod.yaml 
pod/nginx created
[root@server2 ~]# kubectl describe pod nginx 查看镜像详细信息，虽然sever3和server4上都有 disktype=ssd 标签，但是设置了倾向server4，所以会调度到server4

在这里插入图片描述

[root@server2 ~]# vim pod.yaml

在这里插入图片描述

[root@server2 ~]# kubectl delete -f pod.yaml 
pod "nginx" deleted
[root@server2 ~]# kubectl apply -f pod.yaml    创建
pod/nginx created

在这里插入图片描述

2.4 针对pod亲和性和反亲和性

在这里插入图片描述

[root@server2 ~]# kubectl run nginx --image=nginx   运行一个pod
pod/nginx created

[root@server2 ~]# vim pod.yaml 
apiVersion: v1
kind: Pod
metadata:
  name: demo
spec:
  containers:
  - name: nginx
    image: nginx
  affinity:
    podAffinity:
      requiredDuringSchedulingIgnoredDuringExecution:
      - labelSelector:
          matchExpressions:
          - key: run
            operator: In
            values:
            - nginx
        topologyKey: kubernetes.io/hostname
[root@server2 ~]# kubectl  get pod --show-labels   查看pod标签为 run=nginx
NAME    READY   STATUS    RESTARTS   AGE   LABELS
nginx   1/1     Running   0          13m   run=nginx
[root@server2 ~]# vim pod.yaml 
apiVersion: v1
kind: Pod
metadata:
  name: demo
spec:
  containers:
  - name: nginx
    image: nginx
  affinity:
    podAffinity:    表示pod亲和力
      requiredDuringSchedulingIgnoredDuringExecution:
      - labelSelector:
          matchExpressions:
          - key: run                当运行demo时必须和带有run=nginx标签的pod在一起
            operator: In        
            values:
            - nginx
        topologyKey: kubernetes.io/hostname    指定区域，通过主机名区分，也可以通过不同集群区分
[root@server2 ~]# kubectl apply -f pod.yaml    创建
pod/demo created
[root@server2 ~]# kubectl get pod -o wide   查看调度情况，demo和nginx都被调度到server4上
NAME    READY   STATUS    RESTARTS   AGE   IP            NODE      NOMINATED NODE   READINESS GATES
demo    1/1     Running   0          68s   10.244.2.17   server4   <none>           <none>
nginx   1/1     Running   0          20m   10.244.2.16   server4   <none>           <none>

pod反亲和性

[root@server2 ~]# kubectl delete -f pod.yaml   删除之前创建的
pod "demo" deleted
[root@server2 ~]# vim pod.yaml
apiVersion: v1
kind: Pod
metadata:
  name: demo
spec:
  containers:
  - name: nginx
    image: nginx
  affinity:
    podAntiAffinity:      反亲和性
      requiredDuringSchedulingIgnoredDuringExecution:
      - labelSelector:
          matchExpressions:
          - key: run
            operator: In
            values:
            - nginx
        topologyKey: kubernetes.io/hostname
[root@server2 ~]# kubectl apply -f pod.yaml 
pod/demo created
[root@server2 ~]# kubectl get pod -o wide  查看调度情况，demo和nginx在不同的节点上
NAME    READY   STATUS    RESTARTS      AGE   IP            NODE      NOMINATED NODE   READINESS GATES
demo    1/1     Running   0             13s   10.244.1.26   server3   <none>           <none>
nginx   1/1     Running   1 (45m ago)   11h   10.244.2.18   server4   <none>           <none>

2.5 Taints 污点

在这里插入图片描述

实验前先环境清理：
[root@server2 ~]# kubectl delete -f pod.yaml  
pod "demo" deleted

[root@server2 ~]# kubectl get all
NAME        READY   STATUS    RESTARTS        AGE
pod/nginx   1/1     Running   1 (4h30m ago)   15h

NAME                 TYPE        CLUSTER-IP      EXTERNAL-IP   PORT(S)    AGE
service/kubernetes   ClusterIP   10.96.0.1       <none>        443/TCP    4d23h
service/mysql        ClusterIP   None            <none>        3306/TCP   4d15h
service/mysql-read   ClusterIP   10.101.37.222   <none>        3306/TCP   4d15h

NAME                     READY   AGE
statefulset.apps/mysql   0/0     39h

[root@server2 ~]# kubectl delete statefulsets.apps  mysql   删除statefulsets控制器
[root@server2 ~]# kubectl delete svc mysql  删除服务
[root@server2 ~]# kubectl delete svc mysql-read   删除服务
[root@server2 ~]# kubectl delete pvc --all   删除所有pvc

测试：
[root@server2 ~]# kubectl get pod  查看pod，现在就运行一个pod
NAME    READY   STATUS    RESTARTS        AGE
nginx   1/1     Running   1 (4h36m ago)   15h
[root@server2 ~]# kubectl get pod -o wide   查看调度节点，为server4
NAME    READY   STATUS    RESTARTS        AGE   IP            NODE      NOMINATED NODE   READINESS GATES
nginx   1/1     Running   1 (4h36m ago)   15h   10.244.2.18   server4   <none>           <none>
[root@server2 ~]# kubectl taint node server4 key1=v1:NoExecute   在server4上添加污点，server4上没有对应的key1=v1设置，直接躯离
node/server4 tainted
[root@server2 ~]# kubectl get pod  查看pod，直接被回收了
No resources found in default namespace.
[root@server2 ~]# kubectl describe nodes | grep Taints   查询所有节点污点
Taints:             node-role.kubernetes.io/master:NoSchedule
Taints:             <none>
Taints:             key1=v1:NoExecute
[root@server2 ~]# kubectl describe nodes server4 | grep Taints   查询server4节点上的污点
Taints:             key1=v1:NoExecute
[root@server2 ~]# kubectl taint node  server4 key1:NoExecute-    删除server4节点上的污点
node/server4 untainted
[root@server2 ~]# vim pod.yaml 
[root@server2 ~]# kubectl apply -f pod.yaml
[root@server2 ~]# kubectl get pod -o wide   两个pod一个调度到server3一个调度到server4
NAME                          READY   STATUS    RESTARTS   AGE   IP            NODE      NOMINATED NODE   READINESS GATES
web-server-85b98978db-565cs   1/1     Running   0          8s    10.244.1.27   server3   <none>           <none>
web-server-85b98978db-hrwbm   1/1     Running   0          8s    10.244.2.20   server4   <none>           <none>
[root@server2 ~]# kubectl taint node server4 key1=v1:NoSchedule   在server4上加污点，不匹配key和value时，不参加调度，但是不会躯离
node/server4 tainted
[root@server2 ~]# vim pod.yaml

在这里插入图片描述

[root@server2 ~]# kubectl apply -f pod.yaml    创建
deployment.apps/web-server configured
[root@server2 ~]# kubectl get pod -o wide   查看调度情况，都调度到server3上了
NAME                          READY   STATUS    RESTARTS   AGE   IP            NODE      NOMINATED NODE   READINESS GATES
web-server-85b98978db-2zw8q   1/1     Running   0          39s   10.244.1.28   server3   <none>           <none>
web-server-85b98978db-565cs   1/1     Running   0          38m   10.244.1.27   server3   <none>           <none>
web-server-85b98978db-btcst   1/1     Running   0          39s   10.244.1.29   server3   <none>           <none>
web-server-85b98978db-hrwbm   1/1     Running   0          38m   10.244.2.20   server4   <none>           <none>

添加容忍度
在这里插入图片描述

apiVersion: apps/v1
kind: Deployment
metadata:
  name: web-server
spec:
  selector:
    matchLabels:
      app: nginx
  replicas: 4
  template:
    metadata:
      labels:
        app: nginx
    spec:
      containers:
      - name: nginx
        image: nginx
      tolerations:    添加容忍
      - operator: "Exists"     不指定key，就表示匹配所有 key 和 vlaue
        effect: "NoSchedule"   具备NoSchedule这样的容忍度
 [root@server2 ~]# kubectl apply -f pod.yaml   创建
deployment.apps/web-server configured
 [root@server2 ~]# kubectl get pod -o wide  查看调度情况，可以发现容忍了server2和srevr4上存在的污点，在server2和server4都调度了
NAME                          READY   STATUS    RESTARTS   AGE     IP            NODE      NOMINATED NODE   READINESS GATES
web-server-7fdd6fbffc-7l4r5   1/1     Running   0          7m5s    10.244.2.22   server4   <none>           <none>
web-server-7fdd6fbffc-92m56   1/1     Running   0          7m14s   10.244.2.21   server4   <none>           <none>
web-server-7fdd6fbffc-nhbdk   1/1     Running   0          7m6s    10.244.0.22   server2   <none>           <none>
web-server-7fdd6fbffc-xzs7t   1/1     Running   0          7m13s   10.244.1.30   server3   <none>           <none>
[root@server2 ~]# kubectl taint node server3 key1=v1:NoExecute    将server3躯离掉
node/server3 tainted
[root@server2 ~]# kubectl get pod -o wide   查看调度情况，server3被躯离到server2和server4上，因为容忍设置只能容忍NoSchedule
NAME                          READY   STATUS    RESTARTS      AGE   IP            NODE      NOMINATED NODE   READINESS GATES
web-server-7fdd6fbffc-7l4r5   1/1     Running   1 (52m ago)   16h   10.244.2.24   server4   <none>           <none>
web-server-7fdd6fbffc-92m56   1/1     Running   1 (52m ago)   16h   10.244.2.23   server4   <none>           <none>
web-server-7fdd6fbffc-nhbdk   1/1     Running   1 (52m ago)   16h   10.244.0.24   server2   <none>           <none>
web-server-7fdd6fbffc-tcl79   1/1     Running   0             62s   10.244.2.25   server4   <none>           <none>
 [root@server2 ~]# vim pod.yaml

在这里插入图片描述

[root@server2 ~]# kubectl apply -f pod.yaml   创建
deployment.apps/web-server configured
[root@server2 ~]# kubectl get pod -o wide  查看调度情况，可以发现server2、server3、server4都可以调度
NAME                          READY   STATUS    RESTARTS   AGE   IP            NODE      NOMINATED NODE   READINESS GATES
web-server-5d7f8b7699-28zjb   1/1     Running   0          36s   10.244.2.27   server4   <none>           <none>
web-server-5d7f8b7699-5wscd   1/1     Running   0          46s   10.244.2.26   server4   <none>           <none>
web-server-5d7f8b7699-9qsgj   1/1     Running   0          46s   10.244.1.32   server3   <none>           <none>
web-server-5d7f8b7699-kcc6g   1/1     Running   0          46s   10.244.1.33   server3   <none>           <none>
web-server-5d7f8b7699-mjs2q   1/1     Running   0          30s   10.244.0.29   server2   <none>           <none>
web-server-5d7f8b7699-ngxrx   1/1     Running   0          34s   10.244.0.28   server2   <none>           <none>
[root@server2 ~]# kubectl delete -f pod.yaml   回收
deployment.apps "web-server" deleted
[root@server2 ~]# kubectl taint node server3 key1:NoExecute-    删除server3上的污点
node/server3 untainted
[root@server2 ~]# kubectl taint node server4 key1:NoSchedule-   删除server4上的污点
node/server4 untainted

3 影响pod调度的指令

在这里插入图片描述

3.1 cordon—停止调度

[root@server2 ~]# kubectl cordon server3   停止server3调度
node/server3 cordoned
[root@server2 ~]# kubectl get nodes   查看节点
NAME      STATUS                     ROLES                  AGE     VERSION
server2   Ready                      control-plane,master   5d18h   v1.23.5
server3   Ready,SchedulingDisabled   <none>                 5d18h   v1.23.5    server3被停止调度了
server4   Ready                      <none>                 5d18h   v1.23.5
[root@server2 ~]# vim pod.yaml

在这里插入图片描述

[root@server2 ~]# kubectl apply -f pod.yaml   创建
deployment.apps/web-server configured
[root@server2 ~]# kubectl get pod -o wide   查看调度情况，server3不参与调度
NAME                          READY   STATUS    RESTARTS   AGE   IP            NODE      NOMINATED NODE   READINESS GATES
web-server-85b98978db-cjww9   1/1     Running   0          27s   10.244.2.33   server4   <none>           <none>
web-server-85b98978db-gsn2s   1/1     Running   0          36s   10.244.2.31   server4   <none>           <none>
web-server-85b98978db-nbrn9   1/1     Running   0          28s   10.244.2.32   server4   <none>           <none>
web-server-85b98978db-zm44t   1/1     Running   0          36s   10.244.2.30   server4   <none>           <none>

3.2 drain—驱离并停止调度

[root@server2 ~]# kubectl uncordon server3  先恢复server3的调度
node/server3 uncordoned
[root@server2 ~]# kubectl drain server4  驱离
cannot delete DaemonSet-managed Pods (use --ignore-daemonsets to ignore): kube-system/kube-flannel-ds-24kvl, kube-system/kube-proxy-jvgb2      有DaemonSet控制器不让驱离
[root@server2 ~]# kubectl drain server4 --ignore-daemonsets    添加忽略daemonsets，驱离
[root@server2 ~]# kubectl get pod -o wide  查看调度节点情况，server4全部被驱离，全部调度在server3上
NAME                          READY   STATUS    RESTARTS   AGE     IP            NODE      NOMINATED NODE   READINESS GATES
web-server-85b98978db-2pdtp   1/1     Running   0          2m58s   10.244.1.38   server3   <none>           <none>
web-server-85b98978db-csrfp   1/1     Running   0          2m58s   10.244.1.35   server3   <none>           <none>
web-server-85b98978db-dht2r   1/1     Running   0          2m58s   10.244.1.36   server3   <none>           <none>
web-server-85b98978db-gwhsw   1/1     Running   0          2m58s   10.244.1.37   server3   <none>           <none>
[root@server2 ~]# kubectl get  node   
NAME      STATUS                     ROLES                  AGE     VERSION
server2   Ready                      control-plane,master   5d18h   v1.23.5
server3   Ready                      <none>                 5d18h   v1.23.5
server4   Ready,SchedulingDisabled   <none>                 5d18h   v1.23.5   驱离节点上的pod并禁用调度

3.3 delete—删除节点

在这里插入图片描述

注意删除节点时，先驱离该节点上pod，再删除
[root@server2 ~]# kubectl delete nodes server4   删除节点
node "server4" deleted
[root@server2 ~]# kubectl get nodes   查看节点，server4被删除
NAME      STATUS   ROLES                  AGE     VERSION
server2   Ready    control-plane,master   5d19h   v1.23.5
server3   Ready    <none>                 5d19h   v1.23.5
如果从新加入server4
[root@server4 ~]# systemctl restart kubelet   在server4上重启kubelet
[root@server2 ~]# kubectl get nodes   server4会被重新添加上
NAME      STATUS   ROLES                  AGE     VERSION
server2   Ready    control-plane,master   5d19h   v1.23.5
server3   Ready    <none>                 5d19h   v1.23.5
server4   Ready    <none>                 12s     v1.23.5
# kubernetes # 运维
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