node节点选择器，污点、容忍度、亲和性
- node节点选择器
- nodeName，指定pod节点运行在哪个具体node上
- nodeSelector：指定pod调度到具有哪些标签的node节点上
- 亲和性
- node节点亲和性
- 使用requiredDuringSchedulingIgnoredDuringExecution硬亲和性
- 使用preferredDuringSchedulingIgnoredDuringExecution软亲和性
- weight权重
- Pod节点亲和性
- pod自身的亲和性调度有两种表示形式
- 定义两个pod，第一个pod做为基准，第二个pod跟着它走
- pod节点反亲和性
- 定义两个pod，第一个pod做为基准，第二个pod跟它调度节点相反
- topologykey 位置拓扑键
node节点选择器
我们在创建pod资源的时候，pod会根据schduler进行调度，那么默认会调度到随机的一个工作节点，如果我们想要pod调度到指定节点或者调度到一些具有相同特点的node节点，怎么办呢？
可以使用pod中的nodeName或者nodeSelector字段指定要调度到的node节点
nodeName，指定pod节点运行在哪个具体node上
把tomcat.tar.gz上传到k8snode1和k8snode2，手动解压
ctr -n=k8s.io images import tomcat.tar.gz
把busybox.tar.gz上传到k8snode1和k8snode2，手动解压
ctr -n=k8s.io images import busybox.tar.gz
vim pod-node.yaml
apiVersion: v1
kind: Pod
metadata:name: demo-podnamespace: defaultlabels:app: myappenv: dev
spec:nodeName: k8snode1containers:- name: tomcat-pod-javaports:- containerPort: 8080image: tomcat:8.5-jre8-alpineimagePullPolicy: IfNotPresent- name: busyboximage: busybox:latestcommand:- "/bin/sh"- "-c"
- "sleep 3600"
kubectl apply -f pod-node.yaml
查看pod调度到哪个节点
kubectl get pods -o wide
NAME READY STATUS RESTARTS
demo-pod 1/1 Running 0 k8snode1
nodeSelector：指定pod调度到具有哪些标签的node节点上
同一个yaml文件里定义pod资源，如果同时定义了nodeName和NodeSelector，那么条件必须都满足才可以，有一个不满足都会调度失败
给node节点打标签，打个具有disk=ceph的标签
kubectl label nodes k8snode2 disk=ceph
定义pod的时候指定要调度到具有disk=ceph标签的node上
vim pod-1.yaml
apiVersion: v1
kind: Pod
metadata:name: demo-pod-1namespace: defaultlabels:app: myappenv: dev
spec:nodeSelector:disk: cephcontainers:- name: tomcat-pod-javaports:- containerPort: 8080image: tomcat:8.5-jre8-alpineimagePullPolicy: IfNotPresent
kubectl apply -f pod-1.yaml
查看pod调度到哪个节点
kubectl get pods -o wide
NAME READY STATUS RESTARTS
demo-pod-1 1/1 Running 0 k8snode2
做完上面实验，需要把default名称空间下的pod全都删除，kubectl delete pods pod名字
kubectl delete pods demo-pod-1
删除node节点打的标签
kubectl label nodes k8snode2 disk-
亲和性
node节点亲和性
node节点亲和性调度：nodeAffinity，查看官方介绍
kubectl explain pods.spec.affinity
KIND: Pod
VERSION: v1
RESOURCE: affinity <Object>
DESCRIPTION:If specified, the pod's scheduling constraintsAffinity is a group of affinity scheduling rules.
FIELDS:nodeAffinity <Object> #节点亲和性podAffinity <Object> #pod亲和性podAntiAffinity <Object> #pod反亲和性
kubectl explain pods.spec.affinity.nodeAffinity
KIND: Pod
VERSION: v1
RESOURCE: nodeAffinity <Object>
DESCRIPTION:Describes node affinity scheduling rules for the pod.Node affinity is a group of node affinity scheduling rules.
FIELDS:preferredDuringSchedulingIgnoredDuringExecution <[]Object>requiredDuringSchedulingIgnoredDuringExecution <Object>prefered表示有节点尽量满足这个位置定义的亲和性，这不是一个必须的条件，软亲和性
require表示必须有节点满足这个位置定义的亲和性，这是个硬性条件，硬亲和性
使用requiredDuringSchedulingIgnoredDuringExecution硬亲和性
把myapp-v1.tar.gz上传到k8snode2和k8snode1上，手动解压：
ctr -n=k8s.io images import myapp-v1.tar.gz
vim pod-nodeaffinity-demo.yaml
apiVersion: v1
kind: Pod
metadata:name: pod-node-affinity-demonamespace: defaultlabels:app: myapptier: frontend
spec:affinity:nodeAffinity:requiredDuringSchedulingIgnoredDuringExecution:nodeSelectorTerms:- matchExpressions:- key: zoneoperator: Invalues: - foo- barcontainers:- name: myappimage: docker.io/ikubernetes/myapp:v1
imagePullPolicy: IfNotPresent
我们检查当前节点中有任意一个节点拥有zone标签的值是foo或者bar，就可以把pod调度到这个node节点的foo或者bar标签上的节点上
kubectl apply -f pod-nodeaffinity-demo.yaml
kubectl get pods -o wide | grep pod-node
pod-node-affinity-demo 0/1 Pending 0 k8snode1
status的状态是pending，上面说明没有完成调度，因为没有一个拥有zone的标签的值是foo或者bar，而且使用的是硬亲和性，必须满足条件才能完成调度
给这个k8snode1节点打上标签zone=foo，在查看
kubectl label nodes k8snode1 zone=foo
kubectl get pods -o wide
pod-node-affinity-demo 1/1 Running 0 k8snode1
删除pod-nodeaffinity-demo.yaml
kubectl delete -f pod-nodeaffinity-demo.yaml
使用preferredDuringSchedulingIgnoredDuringExecution软亲和性
vim pod-nodeaffinity-demo-2.yaml
apiVersion: v1
kind: Pod
metadata:name: pod-node-affinity-demo-2namespace: defaultlabels:app: myapptier: frontend
spec:containers:- name: myappimage: docker.io/ikubernetes/myapp:v1imagePullPolicy: IfNotPresentaffinity:nodeAffinity:preferredDuringSchedulingIgnoredDuringExecution:- preference:matchExpressions: - key: zone1operator: Invalues:- foo1- bar1weight: 10- preference:matchExpressions:- key: zone2operator: Invalues:- foo2- bar2weight: 20
kubectl apply -f pod-nodeaffinity-demo-2.yaml
kubectl get pods -o wide |grep demo-2
pod-node-affinity-demo-2 1/1 Running 0 k8snode1
上面说明软亲和性是可以运行这个pod的，尽管没有运行这个pod的节点定义的zone1标签
Node节点亲和性针对的是pod和node的关系，Pod调度到node节点的时候匹配的条件
测试完成，删除 pod-nodeaffinity-demo-2.yaml
kubectl delete -f pod-nodeaffinity-demo-2.yaml
weight权重
weight是相对权重，权重越高，pod调度的几率越大
假如给xianchaonode1和xianchaonode2都打上标签
kubectl label nodes k8snode1 zone1=foo1
kubectl label nodes k8snode2 zone2=foo2
vim pod-nodeaffinity-demo-2.yaml
apiVersion: v1
kind: Pod
metadata:name: pod-node-affinity-demo-2namespace: defaultlabels:app: myapptier: frontend
spec:containers:- name: myappimage: docker.io/ikubernetes/myapp:v1imagePullPolicy: IfNotPresentaffinity:nodeAffinity:preferredDuringSchedulingIgnoredDuringExecution:- preference:matchExpressions: - key: zone1operator: Invalues:- foo1- bar1weight: 10- preference:matchExpressions:- key: zone2operator: Invalues:- foo2- bar2weight: 20
kubectl apply -f pod-nodeaffinity-demo-2.yaml
pod在定义node节点亲和性的时候，k8sode1和k8snode2都满足条件，都可以调度pod，且都具有标签，pod在匹配zone2=foo2的权重高，那么pod就会优先调度到k8snode2上
删除对应标签和pod
kubectl delete -f pod-nodeaffinity-demo.yaml
kubectl delete -f pod-nodeaffinity-demo-2.yaml
查看是否还有对应pod未删除
kubectl get pods -owide
Pod节点亲和性
pod自身的亲和性调度有两种表示形式
- podaffinity：pod和pod更倾向腻在一起，把相近的pod结合到相近的位置，如同一区域，同一机架，这样的话pod和pod之间更好通信，比方说有两个机房，这两个机房部署的集群有1000台主机，那么我们希望把nginx和tomcat都部署同一个地方的node节点上，可以提高通信效率；
- podunaffinity：pod和pod更倾向不腻在一起，如果部署两套程序，那么这两套程序更倾向于反亲和性，这样相互之间不会有影响。
- 第一个pod随机选则一个节点，做为评判后续的pod能否到达这个pod所在的节点上的运行方式，这就称为pod亲和性；我们怎么判定哪些节点是相同位置的，哪些节点是不同位置的；我们在定义pod亲和性时需要有一个前提，哪些pod在同一个位置，哪些pod不在同一个位置，这个位置是怎么定义的，标准是什么？以节点名称为标准，这个节点名称相同的表示是同一个位置，节点名称不相同的表示不是一个位置。
kubectl explain pods.spec.affinity.podAffinity
KIND: Pod
VERSION: v1
RESOURCE: podAffinity <Object>
DESCRIPTION:Describes pod affinity scheduling rules (e.g. co-locate this pod in thesame node, zone, etc. as some other pod(s)).Pod affinity is a group of inter pod affinity scheduling rules.
FIELDS:preferredDuringSchedulingIgnoredDuringExecution <[]Object>requiredDuringSchedulingIgnoredDuringExecution <[]Object>requiredDuringSchedulingIgnoredDuringExecution： 硬亲和性
preferredDuringSchedulingIgnoredDuringExecution：软亲和性
kubectl explain pods.spec.affinity.podAffinity.requiredDuringSchedulingIgnoredDuringExecution
KIND: Pod
VERSION: v1
RESOURCE: requiredDuringSchedulingIgnoredDuringExecution <[]Object>
DESCRIPTION:
FIELDS:labelSelector <Object>namespaces <[]string>topologyKey <string> -required-topologyKey：
位置拓扑的键，这个是必须字段
怎么判断是不是同一个位置：
rack=rack1
row=row1
使用rack的键是同一个位置
使用row的键是同一个位置
labelSelector：
我们要判断pod跟别的pod亲和，跟哪个pod亲和，需要靠labelSelector，通过labelSelector选则一组能作为亲和对象的pod资源
namespace：
labelSelector需要选则一组资源，那么这组资源是在哪个名称空间中呢，通过namespace指定，如果不指定namespaces，那么就是当前创建pod的名称空间
定义两个pod，第一个pod做为基准，第二个pod跟着它走
查看默认名称空间有哪些pod,把看到的pod删除，让默认名称空间没有pod
kubectl get pods
创建的pod必须与拥有app=myapp标签的pod在一个节点上
vim pod-required-affinity-demo-1.yaml
apiVersion: v1
kind: Pod
metadata:name: pod-firstlabels:app2: myapp2tier: frontend
spec:containers:- name: myappimage: ikubernetes/myapp:v1imagePullPolicy: IfNotPresentkubectl apply -f pod-required-affinity-demo-1.yaml
vim pod-required-affinity-demo-2.yaml
apiVersion: v1
kind: Pod
metadata:name: pod-secondlabels:app: backendtier: db
spec:containers:- name: busyboximage: busybox:latestimagePullPolicy: IfNotPresentcommand: ["sh","-c","sleep 3600"]affinity:podAffinity:requiredDuringSchedulingIgnoredDuringExecution:- labelSelector:matchExpressions:- {key: app2, operator: In, values: ["myapp2"]}topologyKey: kubernetes.io/hostnamekubectl apply -f pod-required-affinity-demo-2.yaml
第一个pod调度到哪，第二个pod也调度到哪，这就是pod节点亲和性
kubectl get pods -o wide
pod-first running k8snode2
pod-second running k8snode2
删除测试pod
kubectl delete -f pod-required-affinity-demo-1.yaml
kubectl delete -f pod-required-affinity-demo-2.yaml
pod节点反亲和性
定义两个pod，第一个pod做为基准，第二个pod跟它调度节点相反
vim pod-required-anti-affinity-demo-1.yaml
apiVersion: v1
kind: Pod
metadata:name: pod-firstlabels:app1: myapp1tier: frontend
spec:containers:- name: myappimage: ikubernetes/myapp:v1imagePullPolicy: IfNotPresent
kubectl apply -f pod-required-anti-affinity-demo-1.yaml
vim pod-required-anti-affinity-demo-2.yaml
apiVersion: v1
kind: Pod
metadata:name: pod-secondlabels:app: backendtier: db
spec:containers:- name: busyboximage: busybox:latestimagePullPolicy: IfNotPresentcommand: ["sh","-c","sleep 3600"]affinity:podAntiAffinity:requiredDuringSchedulingIgnoredDuringExecution:- labelSelector:matchExpressions:- {key: app1, operator: In, values: ["myapp1"]}topologyKey: kubernetes.io/hostname
kubectl apply -f pod-required-anti-affinity-demo-2.yaml
显示两个pod不在一个node节点上，这就是pod节点反亲和性
kubectl get pods -o wide
pod-first running k8snode1
pod-second running k8snode2删除测试用pod
kubectl delete -f pod-required-anti-affinity-demo-1.yaml
kubectl delete -f pod-required-anti-affinity-demo-2.yaml
topologykey 位置拓扑键
kubectl label nodes k8snode2 zone=foo
kubectl label nodes k8snode1 zone=foo
vim pod-first-required-anti-affinity-demo-1.yaml
apiVersion: v1
kind: Pod
metadata:name: pod-firstlabels:app3: myapp3tier: frontend
spec:containers:- name: myappimage: ikubernetes/myapp:v1imagePullPolicy: IfNotPresent
kubectl apply -f pod-first-required-anti-affinity-demo-1.yaml
vim pod-second-required-anti-affinity-demo-1.yaml
apiVersion: v1
kind: Pod
metadata:name: pod-secondlabels:app: backendtier: db
spec:containers:- name: busyboximage: busybox:latestimagePullPolicy: IfNotPresentcommand: ["sh","-c","sleep 3600"]affinity:podAntiAffinity:requiredDuringSchedulingIgnoredDuringExecution:- labelSelector:matchExpressions:- {key: app3 ,operator: In, values: ["myapp3"]}topologyKey: zone
kubectl apply -f pod-second-required-anti-affinity-demo-1.yaml
kubectl get pods -o wide
显示如下
pod-first running k8snode1
pod-second pending <none>
第二个pod是pending，因为两个节点是同一个位置，现在没有不是同一个位置的了，而且我们要求反亲和性，所以就会处于pending状态，如果在反亲和性这个位置把required改成preferred，那么也会运行。
kubectl delete -f pod-first-required-anti-affinity-demo-1.yaml
kubectl delete -f pod-second-required-anti-affinity-demo-1.yaml
移除标签
kubectl label nodes k8snode1 zone-
kubectl label nodes k8snode2 zone-
- podaffinity：pod节点亲和性，pod倾向于哪个pod
- poduntiaffinity:pod反亲和性
- nodeaffinity：node节点亲和性，pod倾向于哪个node
