k8s 部署pod到指定node

k8s指定节点部署

在一些业务场景中，会需要将一些pod部署到指定node，按照默认的调度规则，pod会优先分配到负载较小的node中，难免会出现多个pod资源竞争的情况。
k8s有两种常用的方法可以实现将指定pod分配到指定node中。

• nodeName

  在部署的yaml文件中，对xxx.spec.nodeName指定节点名称，则该pod将只会在该node上进行部署：

$vim websvr.yaml

apiVersion: apps/v1kind: Deploymentmetadata:name: websvr1-deploymentspec:selector:matchLabels:app: websvr1replicas:3template:metadata:labels:app: websvr1spec:nodeName: k8s-node1#指定节点名称containers:-name: websvr1image: websvr:v1ports:-containerPort:3000---apiVersion: v1kind: Servicemetadata:name: websvr1-servicespec:selector:app: websvr1ports:-protocol: TCPport:3000targetPort:3000

$ kubectl apply -f websvr1.yaml

NAME                                  READY   STATUS    RESTARTS   AGE   IP             NODE        NOMINATED NODE   READINESS GATES
websvr1-deployment-54cffcc8b4-jw9fl1/1     Running0          15s10.244.36.90   k8s-node1<none><none>
websvr1-deployment-54cffcc8b4-s97ln1/1     Running0          15s10.244.36.92   k8s-node1<none><none>
websvr1-deployment-54cffcc8b4-wglpb1/1     Running0          15s10.244.36.91   k8s-node1<none><none>

可以看到websvr只部署在了k8s-node1上，那么如果现在有三个node，一个pod需要部署在其中两个不同node中，是不是要指定两个node的名称呢，其实这种场景可以使用第二种指定分配的方法：

• nodeSelector

  和nodeName不同，nodeSelector是可以指定某一种类型的node进行分配，这种类型在k8s里被称为标签（label）

#查看当前node
$ kubectl get node -o wide

NAME                STATUS   ROLES                  AGE   VERSION   INTERNAL-IP     EXTERNAL-IP   OS-IMAGE         KERNEL-VERSION                 CONTAINER-RUNTIME
k8s-elasticsearch   Ready<none>                 16h   v1.21.0172.16.66.167<none>        CentOS Linux84.18.0-305.19.1.el8_4.x86_64   docker://20.10.9
k8s-master          Ready    control-plane,master   43h   v1.21.0172.16.66.169<none>        CentOS Linux84.18.0-305.19.1.el8_4.x86_64   docker://20.10.9
k8s-node1           Ready<none>                 43h   v1.21.0172.16.66.168<none>        CentOS Linux84.18.0-305.19.1.el8_4.x86_64   docker://20.10.9
k8s-node2           Ready<none>                 43h   v1.21.0172.16.66.170<none>        CentOS Linux84.18.0-305.19.1.el8_4.x86_64   docker://20.10.9#给k8s-node1 k8s-node2打上标签websvr
$ kubectl label nodes k8s-node1 k8s-node2type=websvr#查看type=websvr标签的node
$ kubectl get node -ltype=websvr

NAME        STATUS   ROLES    AGE   VERSION
k8s-node1   Ready<none>   43h   v1.21.0
k8s-node2   Ready<none>   43h   v1.21.0#以下附带标签的其他操作：#修改标签
$ kubectl label nodes k8s-node1 k8s-node2type=webtest --overwrite#查看node标签
$ kubectl get nodes k8s-node1 k8s-node2 --show-labels#删除标签
$ kubectl label nodes k8s-node1 k8s-node2 type-

修改部署yaml

$vim websvr1.yaml

apiVersion: apps/v1kind: Deploymentmetadata:name: websvr1-deploymentspec:selector:matchLabels:app: websvr1replicas:3template:metadata:labels:app: websvr1spec:nodeSelector:#选择标签为type:websvr的node部署type: websvrcontainers:-name: websvr1image: websvr:v1ports:-containerPort:3000---apiVersion: v1kind: Servicemetadata:name: websvr1-servicespec:selector:app: websvr1ports:-protocol: TCPport:3000targetPort:3000

同理修改websvr2.yaml

$vim websvr2.yaml

apiVersion: apps/v1kind: Deploymentmetadata:name: websvr2-deploymentspec:selector:matchLabels:app: websvr2replicas:3template:metadata:labels:app: websvr2spec:nodeSelector:#选择标签为type:websvr的node部署type: websvrcontainers:-name: websvr2image: websvr:v2ports:-containerPort:3001---apiVersion: v1kind: Servicemetadata:name: websvr2-servicespec:selector:app: websvr2ports:-protocol: TCPport:3001targetPort:3001

$ kubectl apply -f websvr1.yaml

$ kubectl apply -f websvr2.yaml

$ kubectl get pods -o wide

NAME                                  READY   STATUS    RESTARTS   AGE     IP               NODE        NOMINATED NODE   READINESS GATES
websvr1-deployment-67fd6cf9d4-cfstc1/1     Running0          2m22s10.244.36.93     k8s-node1<none><none>
websvr1-deployment-67fd6cf9d4-lx6tr1/1     Running0          2m22s10.244.169.151   k8s-node2<none><none>
websvr1-deployment-67fd6cf9d4-zxznp1/1     Running0          2m22s10.244.169.152   k8s-node2<none><none>
websvr2-deployment-67dfc4f674-dz44b1/1     Running0          2m10s10.244.36.95     k8s-node1<none><none>
websvr2-deployment-67dfc4f674-wjg5x1/1     Running0          2m10s10.244.169.153   k8s-node2<none><none>
websvr2-deployment-67dfc4f674-xdk9m1/1     Running0          2m10s10.244.36.94     k8s-node1<none><none>

可以看到此时两个websvr deployment已经部署在指定的node节点上

若有不正确，欢迎指出