如何将k8s中的某些节点单独、仅给某些应用来使用如何将k8s中的某些节点单独、

1、概述
在k8s集群的使用场景中有这样的一种情况，某些机器只给某些特殊的应用来使用。那么，这个时候，需要有以下的2个条件来进行保障：

节点不允许其他的pod来使用
应用只允许被调度到该节点上

2、实现方法
我们如果要实现上述的目标，节点不被其他的pod应用来使用，那么将节点增加taints就可以，然后，pod在调度的时候有可能会被调度到其他的节点上，那么要保证pod只会被调度到这些的节点上，那么，在打了taints的节点上，在增加label即可。

下面是具体的实现的过程。

2.1、节点上增加taints和标签

kubectl taint nodes nccztsjb-node-23 role=master:NoSchedule

这样节点上就不允许没有toleration的pod运行

kubectl label nodes nccztsjb-node-23 dedicated=prod

2.2、pod上设置toleration和nodeSelector

apiVersion: apps/v1 kind: Deployment metadata: name: nginx-taints namespace: default spec: progressDeadlineSeconds: 600 selector: matchLabels: app: nginx-taints replicas: 5 template: metadata: labels: app: nginx-taints spec: containers: - image: 172.20.58.152/middleware/nginx:1.21.4 imagePullPolicy: IfNotPresent name: nginx dnsPolicy: ClusterFirst restartPolicy: Always tolerations: - key: "role" operator: "Exists" effect: "NoSchedule" nodeSelector: dedicated: "prod"

toleration保证pod可以在这个节点上运行，nodeSelector保证pod只在有包含dedicated=prod的标签节点上运行。

运行结果：

kubectl apply -f nginx-taints.yaml

查看pod运行状态

[root@nccztsjb-node-23 ~]# kubectl get pod -l app=nginx-taints -o wide NAMEREADYSTATUSRESTARTSAGEIPNODENOMINATED NODEREADINESS GATES nginx-taints-78b7978fd5-7sjm51/1Running05s172.39.209.112nccztsjb-node-23 nginx-taints-78b7978fd5-97hg91/1Running03s172.39.209.116nccztsjb-node-23 nginx-taints-78b7978fd5-bswrb1/1Running05s172.39.209.113nccztsjb-node-23 nginx-taints-78b7978fd5-lfwzm1/1Running05s172.39.209.114nccztsjb-node-23 nginx-taints-78b7978fd5-vxhfq1/1Running03s172.39.209.115nccztsjb-node-23 [root@nccztsjb-node-23 ~]#

pod的多个实例都运行在nccztsjb-node-23上了。

OK，以上是基本的配置过程。

如果#1：pod没有设置toleration

apiVersion: apps/v1 kind: Deployment metadata: name: nginx-taints namespace: default spec: progressDeadlineSeconds: 600 selector: matchLabels: app: nginx-taints replicas: 5 template: metadata: labels: app: nginx-taints spec: containers: - image: 172.20.58.152/middleware/nginx:1.21.4 imagePullPolicy: IfNotPresent name: nginx dnsPolicy: ClusterFirst restartPolicy: Always #tolerations: #- key: "role" #operator: "Exists" #effect: "NoSchedule" nodeSelector: dedicated: "prod"

运行pod及查看结果

[root@nccztsjb-node-23 ~]# kubectl apply -f nginx-taints.yaml deployment.apps/nginx-taints created [root@nccztsjb-node-23 ~]# kubectl get pod -l app=nginx-taints -o wide NAMEREADYSTATUSRESTARTSAGEIPNODENOMINATED NODEREADINESS GATES nginx-taints-7cfdd85578-67smg0/1Pending01s nginx-taints-7cfdd85578-877zb0/1Pending01s nginx-taints-7cfdd85578-nl8p60/1Pending01s nginx-taints-7cfdd85578-qgf4t0/1Pending01s nginx-taints-7cfdd85578-vw9870/1Pending01s [root@nccztsjb-node-23 ~]#

都未被调度到节点上。

如果#2:节点上未设置nodeSelector

[root@nccztsjb-node-23 ~]# cat nginx-taints.yaml apiVersion: apps/v1 kind: Deployment metadata: name: nginx-taints namespace: default spec: progressDeadlineSeconds: 600 selector: matchLabels: app: nginx-taints replicas: 5 template: metadata: labels: app: nginx-taints spec: containers: - image: 172.20.58.152/middleware/nginx:1.21.4 imagePullPolicy: IfNotPresent name: nginx dnsPolicy: ClusterFirst restartPolicy: Always tolerations: - key: "role" operator: "Exists" effect: "NoSchedule" #nodeSelector: # dedicated: "prod"

运行及查看pod的状态

[root@nccztsjb-node-23 ~]# kubectl apply -f nginx-taints.yaml deployment.apps/nginx-taints created [root@nccztsjb-node-23 ~]# kubectl get pod -l app=nginx-taints -o wide NAMEREADYSTATUSRESTARTSAGEIPNODENOMINATED NODEREADINESS GATES nginx-taints-6cb85bb844-8ggsc1/1Running03s172.39.209.117nccztsjb-node-23 nginx-taints-6cb85bb844-flbf21/1Running03s172.39.21.121nccztsjb-node-25 nginx-taints-6cb85bb844-gjlqm1/1Running03s172.39.21.120nccztsjb-node-25 nginx-taints-6cb85bb844-hrxfr1/1Running03s172.39.157.206nccztsjb-node-24 nginx-taints-6cb85bb844-q9vfk1/1Running03s172.39.157.201nccztsjb-node-24 [root@nccztsjb-node-23 ~]#

【如何将k8s中的某些节点单独、仅给某些应用来使用】这样的结果就是pod可以在任意的节点上运行了，不仅仅是在nccztsjb-node-23节点上。