Kubernetes K8S之Taints污點與Tolerations容忍詳解

頭號碼甲 2022-05-23 發(fā)布于北京

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Kubernetes K8S之Taints污點與Tolerations容忍詳解與示例

主機(jī)配置規(guī)劃

服務(wù)器名稱(hostname)	系統(tǒng)版本	配置	內(nèi)網(wǎng)IP	外網(wǎng)IP(模擬)
k8s-master	CentOS7.7	2C/4G/20G	172.16.1.110	10.0.0.110
k8s-node01	CentOS7.7	2C/4G/20G	172.16.1.111	10.0.0.111
k8s-node02	CentOS7.7	2C/4G/20G	172.16.1.112	10.0.0.112

Taints污點和Tolerations容忍概述

節(jié)點和Pod親和力，是將Pod吸引到一組節(jié)點【根據(jù)拓?fù)溆颉浚ㄗ鳛閮?yōu)選或硬性要求）。污點（Taints）則相反，它們允許一個節(jié)點排斥一組Pod。

容忍（Tolerations）應(yīng)用于pod，允許（但不強(qiáng)制要求）pod調(diào)度到具有匹配污點的節(jié)點上。

污點（Taints）和容忍（Tolerations）共同作用，確保pods不會被調(diào)度到不適當(dāng)?shù)墓?jié)點。一個或多個污點應(yīng)用于節(jié)點；這標(biāo)志著該節(jié)點不應(yīng)該接受任何不容忍污點的Pod。

說明：我們在平常使用中發(fā)現(xiàn)pod不會調(diào)度到k8s的master節(jié)點，就是因為master節(jié)點存在污點。

Taints污點

Taints污點的組成

使用kubectl taint命令可以給某個Node節(jié)點設(shè)置污點，Node被設(shè)置污點之后就和Pod之間存在一種相斥的關(guān)系，可以讓Node拒絕Pod的調(diào)度執(zhí)行，甚至將Node上已經(jīng)存在的Pod驅(qū)逐出去。

每個污點的組成如下：

key=value:effect

每個污點有一個key和value作為污點的標(biāo)簽，effect描述污點的作用。當(dāng)前taint effect支持如下選項：

NoSchedule：表示K8S將不會把Pod調(diào)度到具有該污點的Node節(jié)點上
PreferNoSchedule：表示K8S將盡量避免把Pod調(diào)度到具有該污點的Node節(jié)點上
NoExecute：表示K8S將不會把Pod調(diào)度到具有該污點的Node節(jié)點上，同時會將Node上已經(jīng)存在的Pod驅(qū)逐出去

污點taint的NoExecute詳解

taint 的 effect 值 NoExecute，它會影響已經(jīng)在節(jié)點上運行的 pod：

如果 pod 不能容忍 effect 值為 NoExecute 的 taint，那么 pod 將馬上被驅(qū)逐
如果 pod 能夠容忍 effect 值為 NoExecute 的 taint，且在 toleration 定義中沒有指定 tolerationSeconds，則 pod 會一直在這個節(jié)點上運行。
如果 pod 能夠容忍 effect 值為 NoExecute 的 taint，但是在toleration定義中指定了 tolerationSeconds，則表示 pod 還能在這個節(jié)點上繼續(xù)運行的時間長度。

Taints污點設(shè)置

污點（Taints）查看

k8s master節(jié)點查看

kubectl describe node k8s-master

k8s node查看

kubectl describe node k8s-node01

污點（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./arch=amd64
 8                     beta./os=linux
 9                     cpu-num=12
10                     disk-type=ssd
11                     /arch=amd64
12                     /hostname=k8s-node01
13                     /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./cri-socket: /var/run/dockershim.sock
20                     node.alpha./ttl: 0
21                     volumes./controller-managed-attach-detach: true
22 CreationTimestamp:  Tue, 12 May 2020 16:50:54 +0800
23 Taints:             check=zhang:NoSchedule   ### 可見已添加污點
24 Unschedulable:      false

在k8s-node01節(jié)點添加了一個污點（taint），污點的key為check，value為zhang，污點effect為NoSchedule。這意味著沒有pod可以調(diào)度到k8s-node01節(jié)點，除非具有相匹配的容忍。

污點（Taints）刪除

 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./arch=amd64
10                     beta./os=linux
11                     cpu-num=12
12                     disk-type=ssd
13                     /arch=amd64
14                     /hostname=k8s-node01
15                     /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./cri-socket: /var/run/dockershim.sock
22                     node.alpha./ttl: 0
23                     volumes./controller-managed-attach-detach: true
24 CreationTimestamp:  Tue, 12 May 2020 16:50:54 +0800
25 Taints:             <none>   ### 可見已刪除污點
26 Unschedulable:      false

Tolerations容忍

設(shè)置了污點的Node將根據(jù)taint的effect：NoSchedule、PreferNoSchedule、NoExecute和Pod之間產(chǎn)生互斥的關(guān)系，Pod將在一定程度上不會被調(diào)度到Node上。

但我們可以在Pod上設(shè)置容忍（Tolerations），意思是設(shè)置了容忍的Pod將可以容忍污點的存在，可以被調(diào)度到存在污點的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

重要說明：

其中key、value、effect要與Node上設(shè)置的taint保持一致
operator的值為Exists時，將會忽略value；只要有key和effect就行
tolerationSeconds：表示pod 能夠容忍 effect 值為 NoExecute 的 taint；當(dāng)指定了 tolerationSeconds【容忍時間】，則表示 pod 還能在這個節(jié)點上繼續(xù)運行的時間長度。

當(dāng)不指定key值時

當(dāng)不指定key值和effect值時，且operator為Exists，表示容忍所有的污點【能匹配污點所有的keys，values和effects】

1 tolerations:
2 - operator: "Exists"

當(dāng)不指定effect值時

當(dāng)不指定effect值時，則能匹配污點key對應(yīng)的所有effects情況

1 tolerations:
2 - key: "key"
3   operator: "Exists"

當(dāng)有多個Master存在時

當(dāng)有多個Master存在時，為了防止資源浪費，可以進(jìn)行如下設(shè)置：

1 kubectl taint nodes Node-name node-role./master=:PreferNoSchedule

多個Taints污點和多個Tolerations容忍怎么判斷

可以在同一個node節(jié)點上設(shè)置多個污點（Taints），在同一個pod上設(shè)置多個容忍（Tolerations）。Kubernetes處理多個污點和容忍的方式就像一個過濾器：從節(jié)點的所有污點開始，然后忽略可以被Pod容忍匹配的污點；保留其余不可忽略的污點，污點的effect對Pod具有顯示效果：特別是：

如果有至少一個不可忽略污點，effect為NoSchedule，那么Kubernetes將不調(diào)度Pod到該節(jié)點
如果沒有effect為NoSchedule的不可忽視污點，但有至少一個不可忽視污點，effect為PreferNoSchedule，那么Kubernetes將盡量不調(diào)度Pod到該節(jié)點
如果有至少一個不可忽視污點，effect為NoExecute，那么Pod將被從該節(jié)點驅(qū)逐（如果Pod已經(jīng)在該節(jié)點運行），并且不會被調(diào)度到該節(jié)點（如果Pod還未在該節(jié)點運行）

污點和容忍示例

Node污點為NoExecute的示例

記得把已有的污點清除，以免影響測驗。

節(jié)點上的污點設(shè)置（Taints）

實現(xiàn)如下污點

1 k8s-master 污點為：node-role./master:NoSchedule 【k8s自帶污點，直接使用，不必另外操作添加】
2 k8s-node01 污點為：
3 k8s-node02 污點為：

污點添加操作如下：
「無，本次無污點操作」

污點查看操作如下：

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默認(rèn)的污點，在k8s-node01、k8s-node02無污點。

污點為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 時的格式
28 #      tolerations:
29 #      - key: "check-mem"
30 #        operator: "Equal"
31 #        value: "memdb"
32 #        effect: "NoExecute"
33 #        # 當(dāng)Pod將被驅(qū)逐時，Pod還可以在Node節(jié)點上繼續(xù)保留運行的時間
34 #        tolerationSeconds: 30

運行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>

由上可見，pod是在k8s-node01、k8s-node02平均分布的。

添加effect為NoExecute的污點

kubectl taint nodes k8s-node02 check-mem=memdb:NoExecute

此時所有節(jié)點污點為

1 k8s-master 污點為：node-role./master:NoSchedule 【k8s自帶污點，直接使用，不必另外操作添加】
2 k8s-node01 污點為：
3 k8s-node02 污點為：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>

由上可見，在k8s-node02節(jié)點上的pod已被驅(qū)逐，驅(qū)逐的pod被調(diào)度到了k8s-node01節(jié)點。

Pod沒有容忍時（Tolerations）

記得把已有的污點清除，以免影響測驗。

節(jié)點上的污點設(shè)置（Taints）

實現(xiàn)如下污點

1 k8s-master 污點為：node-role./master:NoSchedule 【k8s自帶污點，直接使用，不必另外操作添加】
2 k8s-node01 污點為：check-nginx=web:PreferNoSchedule
3 k8s-node02 污點為：check-nginx=web:NoSchedule

污點添加操作如下：

1 kubectl taint nodes k8s-node01 check-nginx=web:PreferNoSchedule
2 kubectl taint nodes k8s-node02 check-nginx=web:NoSchedule

污點查看操作如下：

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

無容忍示例

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

運行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>

由上可見，因為k8s-node02節(jié)點的污點check-nginx 的effect為NoSchedule，說明pod不能被調(diào)度到該節(jié)點。此時k8s-node01節(jié)點的污點check-nginx 的effect為PreferNoSchedule【盡量不調(diào)度到該節(jié)點】；但只有該節(jié)點滿足調(diào)度條件，因此都調(diào)度到了k8s-node01節(jié)點。

Pod單個容忍時（Tolerations）

記得把已有的污點清除，以免影響測驗。

節(jié)點上的污點設(shè)置（Taints）

實現(xiàn)如下污點

1 k8s-master 污點為：node-role./master:NoSchedule 【k8s自帶污點，直接使用，不必另外操作添加】
2 k8s-node01 污點為：check-nginx=web:PreferNoSchedule
3 k8s-node02 污點為：check-nginx=web:NoSchedule

污點添加操作如下：

1 kubectl taint nodes k8s-node01 check-nginx=web:PreferNoSchedule
2 kubectl taint nodes k8s-node02 check-nginx=web:NoSchedule

污點查看操作如下：

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

單個容忍示例

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"

運行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>

由上可見，此時pod會盡量【優(yōu)先】調(diào)度到k8s-node02節(jié)點，盡量不調(diào)度到k8s-node01節(jié)點。如果我們只有一個pod，那么會一直調(diào)度到k8s-node02節(jié)點。

Pod多個容忍時（Tolerations）

記得把已有的污點清除，以免影響測驗。

節(jié)點上的污點設(shè)置（Taints）

實現(xiàn)如下污點

1 k8s-master 污點為：node-role./master:NoSchedule 【k8s自帶污點，直接使用，不必另外操作添加】
2 k8s-node01 污點為：check-nginx=web:PreferNoSchedule, check-redis=memdb:NoSchedule
3 k8s-node02 污點為：check-nginx=web:NoSchedule, check-redis=database:NoSchedule

污點添加操作如下：

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

污點查看操作如下：

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

多個容忍示例

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"

運行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>

由上可見，示例中的pod容忍為：check-nginx=web:NoSchedule；check-redis=:NoSchedule。因此pod會盡量調(diào)度到k8s-node02節(jié)點，盡量不調(diào)度到k8s-node01節(jié)點。

Pod容忍指定污點key的所有effects情況

記得把已有的污點清除，以免影響測驗。

節(jié)點上的污點設(shè)置（Taints）

實現(xiàn)如下污點

1 k8s-master 污點為：node-role./master:NoSchedule 【k8s自帶污點，直接使用，不必另外操作添加】
2 k8s-node01 污點為：check-redis=memdb:NoSchedule
3 k8s-node02 污點為：check-redis=database:NoSchedule

污點添加操作如下：

1 kubectl taint nodes k8s-node01 check-redis=memdb:NoSchedule
2 kubectl taint nodes k8s-node02 check-redis=database:NoSchedule

污點查看操作如下：

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

多個容忍示例

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"

運行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>

由上可見，示例中的pod容忍為：check-nginx=:；僅需匹配node污點的key即可，污點的value和effect不需要關(guān)心。因此可以匹配k8s-node01、k8s-node02節(jié)點。

Pod容忍所有污點

記得把已有的污點清除，以免影響測驗。

節(jié)點上的污點設(shè)置（Taints）

實現(xiàn)如下污點

1 k8s-master 污點為：node-role./master:NoSchedule 【k8s自帶污點，直接使用，不必另外操作添加】
2 k8s-node01 污點為：check-nginx=web:PreferNoSchedule, check-redis=memdb:NoSchedule
3 k8s-node02 污點為：check-nginx=web:NoSchedule, check-redis=database:NoSchedule

污點添加操作如下：

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

污點查看操作如下：

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"

運行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>

后上可見，示例中的pod容忍所有的污點，因此pod可被調(diào)度到所有k8s節(jié)點。

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Kubernetes K8S之Taints污點與Tolerations容忍詳解

主機(jī)配置規(guī)劃

Taints污點和Tolerations容忍概述

Taints污點

Taints污點的組成

污點taint的NoExecute詳解

Taints污點設(shè)置

污點（Taints）查看

污點（Taints）添加

污點（Taints）刪除

Tolerations容忍

當(dāng)不指定key值時

當(dāng)不指定effect值時

當(dāng)有多個Master存在時

多個Taints污點和多個Tolerations容忍怎么判斷

污點和容忍示例

Node污點為NoExecute的示例

Pod沒有容忍時（Tolerations）

Pod單個容忍時（Tolerations）

Pod多個容忍時（Tolerations）

Pod容忍指定污點key的所有effects情況

Pod容忍所有污點

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