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Taints污点和Tolerations容忍概述
节点和Pod亲和力，是将Pod吸引到一组节点【根据拓扑域】（作为优选或硬性要求）。污点（Taints）则相反，它们允许一个节点排斥一组Pod。
容忍（Tolerations）应用于pod，允许（但不强制要求）pod调度到具有匹配污点的节点上。
污点（Taints）和容忍（Tolerations）共同作用，确保pods不会被调度到不适当的节点。一个或多个污点应用于节点；这标志着该节点不应该接受任何不容忍污点的Pod。
说明：我们在平常使用中发现pod不会调度到k8s的master节点，就是因为master节点存在污点。
Taints污点
Taints污点的组成
使用kubectl taint命令可以给某个Node节点设置污点，Node被设置污点之后就和Pod之间存在一种相斥的关系，可以让Node拒绝Pod的调度执行，甚至将Node上已经存在的Pod驱逐出去。
每个污点的组成如下：
key=value:effect
每个污点有一个key和value作为污点的标签，effect描述污点的作用。当前taint effect支持如下选项：
- NoSchedule：表示K8S将不会把Pod调度到具有该污点的Node节点上
- PreferNoSchedule：表示K8S将尽量避免把Pod调度到具有该污点的Node节点上
- NoExecute：表示K8S将不会把Pod调度到具有该污点的Node节点上，同时会将Node上已经存在的Pod驱逐出去
污点taint的NoExecute详解
taint 的 effect 值 NoExecute，它会影响已经在节点上运行的 pod：
- 如果 pod 不能容忍 effect 值为 NoExecute 的 taint，那么 pod 将马上被驱逐
- 如果 pod 能够容忍 effect 值为 NoExecute 的 taint，且在 toleration 定义中没有指定 tolerationSeconds，则 pod 会一直在这个节点上运行。
- 如果 pod 能够容忍 effect 值为 NoExecute 的 taint，但是在toleration定义中指定了 tolerationSeconds，则表示 pod 还能在这个节点上继续运行的时间长度。
Taints污点设置
污点（Taints）查看
k8s master节点查看
kubectl describe node k8s-master
k8s node查看
kubectl describe node k8s-node01
污点（Taints）添加
1 [root@k8s-master taint]# kubectl taint nodes k8s-node01 check=zhang:NoSchedule 2 node/k8s-node01 tainted 3 [root@k8s-master taint]# 4 [root@k8s-master taint]# kubectl describe node k8s-node01 5 Name: k8s-node01 6 Roles: <none> 7 Labels: beta.kubernetes.io/arch=amd64 8 beta.kubernetes.io/os=linux 9 cpu-num=12 10 disk-type=ssd 11 kubernetes.io/arch=amd64 12 kubernetes.io/hostname=k8s-node01 13 kubernetes.io/os=linux 14 mem-num=48 15 Annotations: flannel.alpha.coreos.com/backend-data: {"VtepMAC":"3e:15:bb:f8:85:dc"} 16 flannel.alpha.coreos.com/backend-type: vxlan 17 flannel.alpha.coreos.com/kube-subnet-manager: true 18 flannel.alpha.coreos.com/public-ip: 10.0.0.111 19 kubeadm.alpha.kubernetes.io/cri-socket: /var/run/dockershim.sock 20 node.alpha.kubernetes.io/ttl: 0 21 volumes.kubernetes.io/controller-managed-attach-detach: true 22 CreationTimestamp: Tue, 12 May 2020 16:50:54 +0800 23 Taints: check=zhang:NoSchedule ### 可见已添加污点 24 Unschedulable: false
在k8s-node01节点添加了一个污点（taint），污点的key为check，value为zhang，污点effect为NoSchedule。这意味着没有pod可以调度到k8s-node01节点，除非具有相匹配的容忍。
污点（Taints）删除
1 [root@k8s-master taint]# kubectl taint nodes k8s-node01 check:NoExecute- 2 ##### 或者 3 [root@k8s-master taint]# kubectl taint nodes k8s-node01 check=zhang:NoSchedule- 4 node/k8s-node01 untainted 5 [root@k8s-master taint]# 6 [root@k8s-master taint]# kubectl describe node k8s-node01 7 Name: k8s-node01 8 Roles: <none> 9 Labels: beta.kubernetes.io/arch=amd64 10 beta.kubernetes.io/os=linux 11 cpu-num=12 12 disk-type=ssd 13 kubernetes.io/arch=amd64 14 kubernetes.io/hostname=k8s-node01 15 kubernetes.io/os=linux 16 mem-num=48 17 Annotations: flannel.alpha.coreos.com/backend-data: {"VtepMAC":"3e:15:bb:f8:85:dc"} 18 flannel.alpha.coreos.com/backend-type: vxlan 19 flannel.alpha.coreos.com/kube-subnet-manager: true 20 flannel.alpha.coreos.com/public-ip: 10.0.0.111 21 kubeadm.alpha.kubernetes.io/cri-socket: /var/run/dockershim.sock 22 node.alpha.kubernetes.io/ttl: 0 23 volumes.kubernetes.io/controller-managed-attach-detach: true 24 CreationTimestamp: Tue, 12 May 2020 16:50:54 +0800 25 Taints: <none> ### 可见已删除污点 26 Unschedulable: false
Tolerations容忍
设置了污点的Node将根据taint的effect：NoSchedule、PreferNoSchedule、NoExecute和Pod之间产生互斥的关系，Pod将在一定程度上不会被调度到Node上。
但我们可以在Pod上设置容忍（Tolerations），意思是设置了容忍的Pod将可以容忍污点的存在，可以被调度到存在污点的Node上。
pod.spec.tolerations示例
1 tolerations: 2 - key: "key" 3 operator: "Equal" 4 value: "value" 5 effect: "NoSchedule" 6 --- 7 tolerations: 8 - key: "key" 9 operator: "Exists" 10 effect: "NoSchedule" 11 --- 12 tolerations: 13 - key: "key" 14 operator: "Equal" 15 value: "value" 16 effect: "NoExecute" 17 tolerationSeconds: 3600
重要说明：
- 其中key、value、effect要与Node上设置的taint保持一致
- operator的值为Exists时，将会忽略value；只要有key和effect就行
- tolerationSeconds：表示pod 能够容忍 effect 值为 NoExecute 的 taint；当指定了 tolerationSeconds【容忍时间】，则表示 pod 还能在这个节点上继续运行的时间长度。
当不指定key值时
当不指定key值和effect值时，且operator为Exists，表示容忍所有的污点【能匹配污点所有的keys，values和effects】
1 tolerations: 2 - operator: "Exists"
当不指定effect值时
当不指定effect值时，则能匹配污点key对应的所有effects情况
1 tolerations: 2 - key: "key" 3 operator: "Exists"
当有多个Master存在时
当有多个Master存在时，为了防止资源浪费，可以进行如下设置：
1 kubectl taint nodes Node-name node-role.kubernetes.io/master=:PreferNoSchedule多个Taints污点和多个Tolerations容忍怎么判断
可以在同一个node节点上设置多个污点（Taints），在同一个pod上设置多个容忍（Tolerations）。Kubernetes处理多个污点和容忍的方式就像一个过滤器：从节点的所有污点开始，然后忽略可以被Pod容忍匹配的污点；保留其余不可忽略的污点，污点的effect对Pod具有显示效果：特别是：
- 如果有至少一个不可忽略污点，effect为NoSchedule，那么Kubernetes将不调度Pod到该节点
- 如果没有effect为NoSchedule的不可忽视污点，但有至少一个不可忽视污点，effect为PreferNoSchedule，那么Kubernetes将尽量不调度Pod到该节点
- 如果有至少一个不可忽视污点，effect为NoExecute，那么Pod将被从该节点驱逐（如果Pod已经在该节点运行），并且不会被调度到该节点（如果Pod还未在该节点运行）
污点和容忍示例
Node污点为NoExecute的示例
记得把已有的污点清除，以免影响测验。
节点上的污点设置（Taints）
实现如下污点
1 k8s-master 污点为：node-role.kubernetes.io/master:NoSchedule 【k8s自带污点，直接使用，不必另外操作添加】 2 k8s-node01 污点为： 3 k8s-node02 污点为：
污点添加操作如下：
「无，本次无污点操作」
污点查看操作如下：
1 kubectl describe node k8s-master | grep 'Taints' -A 5 2 kubectl describe node k8s-node01 | grep 'Taints' -A 5 3 kubectl describe node k8s-node02 | grep 'Taints' -A 5
除了k8s-master默认的污点，在k8s-node01、k8s-node02无污点。
污点为NoExecute示例
yaml文件
1 [root@k8s-master taint]# pwd 2 /root/k8s_practice/scheduler/taint 3 [root@k8s-master taint]# 4 [root@k8s-master taint]# cat noexecute_tolerations.yaml 5 apiVersion: apps/v1 6 kind: Deployment 7 metadata: 8 name: noexec-tolerations-deploy 9 labels: 10 app: noexectolerations-deploy 11 spec: 12 replicas: 6 13 selector: 14 matchLabels: 15 app: myapp 16 template: 17 metadata: 18 labels: 19 app: myapp 20 spec: 21 containers: 22 - name: myapp-pod 23 image: registry.cn-beijing.aliyuncs.com/google_registry/myapp:v1 24 imagePullPolicy: IfNotPresent 25 ports: 26 - containerPort: 80 27 # 有容忍并有 tolerationSeconds 时的格式 28 # tolerations: 29 # - key: "check-mem" 30 # operator: "Equal" 31 # value: "memdb" 32 # effect: "NoExecute" 33 # # 当Pod将被驱逐时，Pod还可以在Node节点上继续保留运行的时间 34 # tolerationSeconds: 30
运行yaml文件
1 [root@k8s-master taint]# kubectl apply -f noexecute_tolerations.yaml 2 deployment.apps/noexec-tolerations-deploy created 3 [root@k8s-master taint]# 4 [root@k8s-master taint]# kubectl get deploy -o wide 5 NAME READY UP-TO-DATE AVAILABLE AGE CONTAINERS IMAGES SELECTOR 6 noexec-tolerations-deploy 6/6 6 6 10s myapp-pod registry.cn-beijing.aliyuncs.com/google_registry/myapp:v1 app=myapp 7 [root@k8s-master taint]# 8 [root@k8s-master taint]# kubectl get pod -o wide 9 NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES 10 noexec-tolerations-deploy-85587896f9-2j848 1/1 Running 0 15s 10.244.4.101 k8s-node01 <none> <none> 11 noexec-tolerations-deploy-85587896f9-jgqkn 1/1 Running 0 15s 10.244.2.141 k8s-node02 <none> <none> 12 noexec-tolerations-deploy-85587896f9-jmw5w 1/1 Running 0 15s 10.244.2.142 k8s-node02 <none> <none> 13 noexec-tolerations-deploy-85587896f9-s8x95 1/1 Running 0 15s 10.244.4.102 k8s-node01 <none> <none> 14 noexec-tolerations-deploy-85587896f9-t82fj 1/1 Running 0 15s 10.244.4.103 k8s-node01 <none> <none> 15 noexec-tolerations-deploy-85587896f9-wx9pz 1/1 Running 0 15s 10.244.2.143 k8s-node02 <none> <none>
由上可见，pod是在k8s-node01、k8s-node02平均分布的。
添加effect为NoExecute的污点
kubectl taint nodes k8s-node02 check-mem=memdb:NoExecute
此时所有节点污点为
1 k8s-master 污点为：node-role.kubernetes.io/master:NoSchedule 【k8s自带污点，直接使用，不必另外操作添加】 2 k8s-node01 污点为： 3 k8s-node02 污点为：check-mem=memdb:NoExecute
之后再次查看pod信息
1 [root@k8s-master taint]# kubectl get pod -o wide 2 NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES 3 noexec-tolerations-deploy-85587896f9-2j848 1/1 Running 0 2m2s 10.244.4.101 k8s-node01 <none> <none> 4 noexec-tolerations-deploy-85587896f9-ch96j 1/1 Running 0 8s 10.244.4.106 k8s-node01 <none> <none> 5 noexec-tolerations-deploy-85587896f9-cjrkb 1/1 Running 0 8s 10.244.4.105 k8s-node01 <none> <none> 6 noexec-tolerations-deploy-85587896f9-qbq6d 1/1 Running 0 7s 10.244.4.104 k8s-node01 <none> <none> 7 noexec-tolerations-deploy-85587896f9-s8x95 1/1 Running 0 2m2s 10.244.4.102 k8s-node01 <none> <none> 8 noexec-tolerations-deploy-85587896f9-t82fj 1/1 Running 0 2m2s 10.244.4.103 k8s-node01 <none> <none>
由上可见，在k8s-node02节点上的pod已被驱逐，驱逐的pod被调度到了k8s-node01节点。
Pod没有容忍时（Tolerations）
记得把已有的污点清除，以免影响测验。
节点上的污点设置（Taints）
实现如下污点
1 k8s-master 污点为：node-role.kubernetes.io/master:NoSchedule 【k8s自带污点，直接使用，不必另外操作添加】 2 k8s-node01 污点为：check-nginx=web:PreferNoSchedule 3 k8s-node02 污点为：check-nginx=web:NoSchedule
污点添加操作如下：
1 kubectl taint nodes k8s-node01 check-nginx=web:PreferNoSchedule 2 kubectl taint nodes k8s-node02 check-nginx=web:NoSchedule
污点查看操作如下：
1 kubectl describe node k8s-master | grep 'Taints' -A 5 2 kubectl describe node k8s-node01 | grep 'Taints' -A 5 3 kubectl describe node k8s-node02 | grep 'Taints' -A 5
无容忍示例
yaml文件
1 [root@k8s-master taint]# pwd 2 /root/k8s_practice/scheduler/taint 3 [root@k8s-master taint]# 4 [root@k8s-master taint]# cat no_tolerations.yaml 5 apiVersion: apps/v1 6 kind: Deployment 7 metadata: 8 name: no-tolerations-deploy 9 labels: 10 app: notolerations-deploy 11 spec: 12 replicas: 5 13 selector: 14 matchLabels: 15 app: myapp 16 template: 17 metadata: 18 labels: 19 app: myapp 20 spec: 21 containers: 22 - name: myapp-pod 23 image: registry.cn-beijing.aliyuncs.com/google_registry/myapp:v1 24 imagePullPolicy: IfNotPresent 25 ports: 26 - containerPort: 80
运行yaml文件
1 [root@k8s-master taint]# kubectl apply -f no_tolerations.yaml 2 deployment.apps/no-tolerations-deploy created 3 [root@k8s-master taint]# 4 [root@k8s-master taint]# kubectl get deploy -o wide 5 NAME READY UP-TO-DATE AVAILABLE AGE CONTAINERS IMAGES SELECTOR 6 no-tolerations-deploy 5/5 5 5 9s myapp-pod registry.cn-beijing.aliyuncs.com/google_registry/myapp:v1 app=myapp 7 [root@k8s-master taint]# 8 [root@k8s-master taint]# kubectl get pod -o wide 9 NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES 10 no-tolerations-deploy-85587896f9-6bjv8 1/1 Running 0 16s 10.244.4.54 k8s-node01 <none> <none> 11 no-tolerations-deploy-85587896f9-hbbjb 1/1 Running 0 16s 10.244.4.58 k8s-node01 <none> <none> 12 no-tolerations-deploy-85587896f9-jlmzw 1/1 Running 0 16s 10.244.4.56 k8s-node01 <none> <none> 13 no-tolerations-deploy-85587896f9-kfh2c 1/1 Running 0 16s 10.244.4.55 k8s-node01 <none> <none> 14 no-tolerations-deploy-85587896f9-wmp8b 1/1 Running 0 16s 10.244.4.57 k8s-node01 <none> <none>
由上可见，因为k8s-node02节点的污点check-nginx 的effect为NoSchedule，说明pod不能被调度到该节点。此时k8s-node01节点的污点check-nginx 的effect为PreferNoSchedule【尽量不调度到该节点】；但只有该节点满足调度条件，因此都调度到了k8s-node01节点。
Pod单个容忍时（Tolerations）
记得把已有的污点清除，以免影响测验。
节点上的污点设置（Taints）
实现如下污点
1 k8s-master 污点为：node-role.kubernetes.io/master:NoSchedule 【k8s自带污点，直接使用，不必另外操作添加】 2 k8s-node01 污点为：check-nginx=web:PreferNoSchedule 3 k8s-node02 污点为：check-nginx=web:NoSchedule
污点添加操作如下：
1 kubectl taint nodes k8s-node01 check-nginx=web:PreferNoSchedule 2 kubectl taint nodes k8s-node02 check-nginx=web:NoSchedule
污点查看操作如下：
1 kubectl describe node k8s-master | grep 'Taints' -A 5 2 kubectl describe node k8s-node01 | grep 'Taints' -A 5 3 kubectl describe node k8s-node02 | grep 'Taints' -A 5
单个容忍示例
yaml文件
1 [root@k8s-master taint]# pwd 2 /root/k8s_practice/scheduler/taint 3 [root@k8s-master taint]# 4 [root@k8s-master taint]# cat one_tolerations.yaml 5 apiVersion: apps/v1 6 kind: Deployment 7 metadata: 8 name: one-tolerations-deploy 9 labels: 10 app: onetolerations-deploy 11 spec: 12 replicas: 6 13 selector: 14 matchLabels: 15 app: myapp 16 template: 17 metadata: 18 labels: 19 app: myapp 20 spec: 21 containers: 22 - name: myapp-pod 23 image: registry.cn-beijing.aliyuncs.com/google_registry/myapp:v1 24 imagePullPolicy: IfNotPresent 25 ports: 26 - containerPort: 80 27 tolerations: 28 - key: "check-nginx" 29 operator: "Equal" 30 value: "web" 31 effect: "NoSchedule"
运行yaml文件
1 [root@k8s-master taint]# kubectl apply -f one_tolerations.yaml 2 deployment.apps/one-tolerations-deploy created 3 [root@k8s-master taint]# 4 [root@k8s-master taint]# kubectl get deploy -o wide 5 NAME READY UP-TO-DATE AVAILABLE AGE CONTAINERS IMAGES SELECTOR 6 one-tolerations-deploy 6/6 6 6 3s myapp-pod registry.cn-beijing.aliyuncs.com/google_registry/myapp:v1 app=myapp 7 [root@k8s-master taint]# 8 [root@k8s-master taint]# kubectl get pod -o wide 9 NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES 10 one-tolerations-deploy-5757d6b559-gbj49 1/1 Running 0 7s 10.244.2.73 k8s-node02 <none> <none> 11 one-tolerations-deploy-5757d6b559-j9p6r 1/1 Running 0 7s 10.244.2.71 k8s-node02 <none> <none> 12 one-tolerations-deploy-5757d6b559-kpk9q 1/1 Running 0 7s 10.244.2.72 k8s-node02 <none> <none> 13 one-tolerations-deploy-5757d6b559-lsppn 1/1 Running 0 7s 10.244.4.65 k8s-node01 <none> <none> 14 one-tolerations-deploy-5757d6b559-rx72g 1/1 Running 0 7s 10.244.4.66 k8s-node01 <none> <none> 15 one-tolerations-deploy-5757d6b559-s8qr9 1/1 Running 0 7s 10.244.2.74 k8s-node02 <none> <none>
由上可见，此时pod会尽量【优先】调度到k8s-node02节点，尽量不调度到k8s-node01节点。如果我们只有一个pod，那么会一直调度到k8s-node02节点。
Pod多个容忍时（Tolerations）
记得把已有的污点清除，以免影响测验。
节点上的污点设置（Taints）
实现如下污点
1 k8s-master 污点为：node-role.kubernetes.io/master:NoSchedule 【k8s自带污点，直接使用，不必另外操作添加】 2 k8s-node01 污点为：check-nginx=web:PreferNoSchedule, check-redis=memdb:NoSchedule 3 k8s-node02 污点为：check-nginx=web:NoSchedule, check-redis=database:NoSchedule
污点添加操作如下：
1 kubectl taint nodes k8s-node01 check-nginx=web:PreferNoSchedule 2 kubectl taint nodes k8s-node01 check-redis=memdb:NoSchedule 3 kubectl taint nodes k8s-node02 check-nginx=web:NoSchedule 4 kubectl taint nodes k8s-node02 check-redis=database:NoSchedule
污点查看操作如下：
1 kubectl describe node k8s-master | grep 'Taints' -A 5 2 kubectl describe node k8s-node01 | grep 'Taints' -A 5 3 kubectl describe node k8s-node02 | grep 'Taints' -A 5
多个容忍示例
yaml文件
1 [root@k8s-master taint]# pwd 2 /root/k8s_practice/scheduler/taint 3 [root@k8s-master taint]# 4 [root@k8s-master taint]# cat multi_tolerations.yaml 5 apiVersion: apps/v1 6 kind: Deployment 7 metadata: 8 name: multi-tolerations-deploy 9 labels: 10 app: multitolerations-deploy 11 spec: 12 replicas: 6 13 selector: 14 matchLabels: 15 app: myapp 16 template: 17 metadata: 18 labels: 19 app: myapp 20 spec: 21 containers: 22 - name: myapp-pod 23 image: registry.cn-beijing.aliyuncs.com/google_registry/myapp:v1 24 imagePullPolicy: IfNotPresent 25 ports: 26 - containerPort: 80 27 tolerations: 28 - key: "check-nginx" 29 operator: "Equal" 30 value: "web" 31 effect: "NoSchedule" 32 - key: "check-redis" 33 operator: "Exists" 34 effect: "NoSchedule"
运行yaml文件
1 [root@k8s-master taint]# kubectl apply -f multi_tolerations.yaml 2 deployment.apps/multi-tolerations-deploy created 3 [root@k8s-master taint]# 4 [root@k8s-master taint]# kubectl get deploy -o wide 5 NAME READY UP-TO-DATE AVAILABLE AGE CONTAINERS IMAGES SELECTOR 6 multi-tolerations-deploy 6/6 6 6 5s myapp-pod registry.cn-beijing.aliyuncs.com/google_registry/myapp:v1 app=myapp 7 [root@k8s-master taint]# 8 [root@k8s-master taint]# kubectl get pod -o wide 9 NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES 10 multi-tolerations-deploy-776ff4449c-2csnk 1/1 Running 0 10s 10.244.2.171 k8s-node02 <none> <none> 11 multi-tolerations-deploy-776ff4449c-4d9fh 1/1 Running 0 10s 10.244.4.116 k8s-node01 <none> <none> 12 multi-tolerations-deploy-776ff4449c-c8fz5 1/1 Running 0 10s 10.244.2.173 k8s-node02 <none> <none> 13 multi-tolerations-deploy-776ff4449c-nj29f 1/1 Running 0 10s 10.244.4.115 k8s-node01 <none> <none> 14 multi-tolerations-deploy-776ff4449c-r7gsm 1/1 Running 0 10s 10.244.2.172 k8s-node02 <none> <none> 15 multi-tolerations-deploy-776ff4449c-s8t2n 1/1 Running 0 10s 10.244.2.174 k8s-node02 <none> <none>
由上可见，示例中的pod容忍为：check-nginx=web:NoSchedule；check-redis=:NoSchedule。因此pod会尽量调度到k8s-node02节点，尽量不调度到k8s-node01节点。
Pod容忍指定污点key的所有effects情况
记得把已有的污点清除，以免影响测验。
节点上的污点设置（Taints）
实现如下污点
1 k8s-master 污点为：node-role.kubernetes.io/master:NoSchedule 【k8s自带污点，直接使用，不必另外操作添加】 2 k8s-node01 污点为：check-redis=memdb:NoSchedule 3 k8s-node02 污点为：check-redis=database:NoSchedule
污点添加操作如下：
1 kubectl taint nodes k8s-node01 check-redis=memdb:NoSchedule 2 kubectl taint nodes k8s-node02 check-redis=database:NoSchedule
污点查看操作如下：
1 kubectl describe node k8s-master | grep 'Taints' -A 5 2 kubectl describe node k8s-node01 | grep 'Taints' -A 5 3 kubectl describe node k8s-node02 | grep 'Taints' -A 5
多个容忍示例
yaml文件
1 [root@k8s-master taint]# pwd 2 /root/k8s_practice/scheduler/taint 3 [root@k8s-master taint]# 4 [root@k8s-master taint]# cat key_tolerations.yaml 5 apiVersion: apps/v1 6 kind: Deployment 7 metadata: 8 name: key-tolerations-deploy 9 labels: 10 app: keytolerations-deploy 11 spec: 12 replicas: 6 13 selector: 14 matchLabels: 15 app: myapp 16 template: 17 metadata: 18 labels: 19 app: myapp 20 spec: 21 containers: 22 - name: myapp-pod 23 image: registry.cn-beijing.aliyuncs.com/google_registry/myapp:v1 24 imagePullPolicy: IfNotPresent 25 ports: 26 - containerPort: 80 27 tolerations: 28 - key: "check-redis" 29 operator: "Exists"
运行yaml文件
1 [root@k8s-master taint]# kubectl apply -f key_tolerations.yaml 2 deployment.apps/key-tolerations-deploy created 3 [root@k8s-master taint]# 4 [root@k8s-master taint]# kubectl get deploy -o wide 5 NAME READY UP-TO-DATE AVAILABLE AGE CONTAINERS IMAGES SELECTOR 6 key-tolerations-deploy 6/6 6 6 21s myapp-pod registry.cn-beijing.aliyuncs.com/google_registry/myapp:v1 app=myapp 7 [root@k8s-master taint]# 8 [root@k8s-master taint]# kubectl get pod -o wide 9 NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES 10 key-tolerations-deploy-db5c4c4db-2zqr8 1/1 Running 0 26s 10.244.2.170 k8s-node02 <none> <none> 11 key-tolerations-deploy-db5c4c4db-5qb5p 1/1 Running 0 26s 10.244.4.113 k8s-node01 <none> <none> 12 key-tolerations-deploy-db5c4c4db-7xmt6 1/1 Running 0 26s 10.244.2.169 k8s-node02 <none> <none> 13 key-tolerations-deploy-db5c4c4db-84rkj 1/1 Running 0 26s 10.244.4.114 k8s-node01 <none> <none> 14 key-tolerations-deploy-db5c4c4db-gszxg 1/1 Running 0 26s 10.244.2.168 k8s-node02 <none> <none> 15 key-tolerations-deploy-db5c4c4db-vlgh8 1/1 Running 0 26s 10.244.4.112 k8s-node01 <none> <none>
由上可见，示例中的pod容忍为：check-nginx=:；仅需匹配node污点的key即可，污点的value和effect不需要关心。因此可以匹配k8s-node01、k8s-node02节点。
Pod容忍所有污点
记得把已有的污点清除，以免影响测验。
节点上的污点设置（Taints）
实现如下污点
1 k8s-master 污点为：node-role.kubernetes.io/master:NoSchedule 【k8s自带污点，直接使用，不必另外操作添加】 2 k8s-node01 污点为：check-nginx=web:PreferNoSchedule, check-redis=memdb:NoSchedule 3 k8s-node02 污点为：check-nginx=web:NoSchedule, check-redis=database:NoSchedule
污点添加操作如下：
1 kubectl taint nodes k8s-node01 check-nginx=web:PreferNoSchedule 2 kubectl taint nodes k8s-node01 check-redis=memdb:NoSchedule 3 kubectl taint nodes k8s-node02 check-nginx=web:NoSchedule 4 kubectl taint nodes k8s-node02 check-redis=database:NoSchedule
污点查看操作如下：
1 kubectl describe node k8s-master | grep 'Taints' -A 5 2 kubectl describe node k8s-node01 | grep 'Taints' -A 5 3 kubectl describe node k8s-node02 | grep 'Taints' -A 5
所有容忍示例
yaml文件
1 [root@k8s-master taint]# pwd 2 /root/k8s_practice/scheduler/taint 3 [root@k8s-master taint]# 4 [root@k8s-master taint]# cat all_tolerations.yaml 5 apiVersion: apps/v1 6 kind: Deployment 7 metadata: 8 name: all-tolerations-deploy 9 labels: 10 app: alltolerations-deploy 11 spec: 12 replicas: 6 13 selector: 14 matchLabels: 15 app: myapp 16 template: 17 metadata: 18 labels: 19 app: myapp 20 spec: 21 containers: 22 - name: myapp-pod 23 image: registry.cn-beijing.aliyuncs.com/google_registry/myapp:v1 24 imagePullPolicy: IfNotPresent 25 ports: 26 - containerPort: 80 27 tolerations: 28 - operator: "Exists"
运行yaml文件
1 [root@k8s-master taint]# kubectl apply -f all_tolerations.yaml 2 deployment.apps/all-tolerations-deploy created 3 [root@k8s-master taint]# 4 [root@k8s-master taint]# kubectl get deploy -o wide 5 NAME READY UP-TO-DATE AVAILABLE AGE CONTAINERS IMAGES SELECTOR 6 all-tolerations-deploy 6/6 6 6 8s myapp-pod registry.cn-beijing.aliyuncs.com/google_registry/myapp:v1 app=myapp 7 [root@k8s-master taint]# 8 [root@k8s-master taint]# kubectl get pod -o wide 9 NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES 10 all-tolerations-deploy-566cdccbcd-4klc2 1/1 Running 0 12s 10.244.0.116 k8s-master <none> <none> 11 all-tolerations-deploy-566cdccbcd-59vvc 1/1 Running 0 12s 10.244.0.115 k8s-master <none> <none> 12 all-tolerations-deploy-566cdccbcd-cvw4s 1/1 Running 0 12s 10.244.2.175 k8s-node02 <none> <none> 13 all-tolerations-deploy-566cdccbcd-k8fzl 1/1 Running 0 12s 10.244.2.176 k8s-node02 <none> <none> 14 all-tolerations-deploy-566cdccbcd-s2pw7 1/1 Running 0 12s 10.244.4.118 k8s-node01 <none> <none> 15 all-tolerations-deploy-566cdccbcd-xzngt 1/1 Running 0 13s 10.244.4.117 k8s-node01 <none> <none>
后上可见，示例中的pod容忍所有的污点，因此pod可被调度到所有k8s节点。
相关阅读
1、官网：污点与容忍
2、Kubernetes K8S调度器kube-scheduler详解
3、Kubernetes K8S之affinity亲和性与反亲和性详解与示例
完毕！
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