调度管理 - 容器相关

##限制注意：

####1、同时指定nodeSelector 和 nodeAffinity，pod必须都满足
####2、nodeAffinity有多个nodeSelectorTerms ，pod只需满足一个
####3、nodeSelectorTerms多个matchExpressions ，pod必须都满足
####4、由于IgnoredDuringExecution，所以改变labels不会影响已经运行pod

---
#节点调度
##方式一：直接指定
	apiVersion: v1
	kind: pod
	metadata:
	  name: examplepod
	spec:
	  containers:
	  - name: examplepod-container
	     image: busybox
		 imagePullPolicy: IfNotPresent
		 command: ['sh','-c]
		 args: ['echo ""hello world";sleep 36000']
	  nodeName: work01			#直接指定pod调度到work01节点上
---
##方式二：节点标签
####先给节点打标签
	kubectl label nodes work01 app=nginx
	
####创建pod的yaml文件
	apiVersion: v1
	kind: pod
	metadata:
	  name: examplepod
	spec:
	  containers:
	  - name: examplepod-container
	     image: busybox
	     imagePullPolicy: IfNotPresent
	     command: ['sh','-c]
	     args: ['echo ""hello world";sleep 36000']
	   nodeSelector:
	     app: nginx				#调度到标签为app:nginx的节点上
---
#亲和性调度
##节点亲和性（基于标签指定法）
####先给节点打标签
	kubectl label nodes work01 app=nginx,relase=state,version=1.12

####创建pod的yaml文件
	apiVersion: v1
	kind: pod
	metadata:
	  name: examplepod
	spec:
 	 containers:
	  - name: examplepod-container
	     image: busybox
	     imagePullPolicy: IfNotPresent
	     command: ['sh','-c]
	     args: ['echo ""hello world";sleep 36000']
	  affinity:
	    nodeAffinity:
		  requiredDuringSchedulingIgnoredDuringExecution:
		    nodeSelectorTerms:
			- matchExpressions:
			  - {key: app, operator: In, values: [nginx,web]}
			  - {key: relase, operator:NotIn, values:[test]}
		  preferredDuringSchedulingIgnoredDuringExecution:
		  - weight: 1
		    preference:
			  matchExpressions:
			  - {key:version operator: In, values:[1.12,1.13]}
---
##注意：
####1、requiredDuringScheduingIgnoredDuringExecution与requiredDuringScheduingRequiredDuringExecution的区别在于，后者Pod调度成功运行后，如果节点标签发生变化而不再满足条件，Pod将会驱逐出节点，而前者不会
####2、requiredDuringSchedulingIgnoredDuringExecution为硬限制，preferredDuringSchedulingIgnoredDuringExecution为软限制。

---
##Pod亲和性
####注意：Pod的亲和性和反亲和性调度会涉及大量调度运算，会显著减慢在大型集群中的调度，不建议在大于几百哥节点的集群中使用它们
---
####创建pod的yaml文件
	apiVersion: v1
	kind: pod
	metadata:
	  name: examplepod
	spec:
	  containers:
	  - name: examplepod-container
	     image: busybox
	     imagePullPolicy: IfNotPresent
	     command: ['sh','-c]
	     args: ['echo ""hello world";sleep 36000']
	  affinity:
	    podAffinity:		#亲和
		  requiredDuringSchedulingIgnoredDuringExecution:
		  - labelSelector:
		      matchExpressions:
			  - {key: app, operator: In, values: [nginx,web]}
			  - {key: relase, operator:NotIn, values:[test]}
			topologyKey:'Kubernetes.io/hostname'
		  preferredDuringSchedulingIgnoredDuringExecutio:
		  - weight: 1
		    podAffinityTerm:
			  labelSelector:
			    matchExpressions:
			    - {key:version operator: In, values:[1.12,1.13]}
			  topologyKey:'Kubernetes.io/hostname'
---
####以上示例设置：
####1、硬亲和条件，寻找app标签在[nginx,web]和relase寻找app标签在不在test中的Pod,硬亲和条件key标签在[1.12,1.13]中。
####2、weight字段表示相对于其它软亲和条件的优先级，取值1~100，越大优先级越高
####3、topologyKey:'Kubernetes.io/hostname',表示如果满足亲和性条件，则会将Pod调度到和已有Pod所在节点的ubernetes.io/hostname标签值相同的节点上，对于此示例，也就是说，会将该Pod调度到同一台机器上。

---
##Pod反亲和性
####创建pod的yaml文件
	apiVersion: v1
	kind: pod
	metadata:
	  name: examplepod
	spec:
	  containers:
	  - name: examplepod-container
	     image: busybox
	     imagePullPolicy: IfNotPresent
	     command: ['sh','-c]
	     args: ['echo ""hello world";sleep 36000']
	  affinity:
	    podAntiAffinity:		#反亲和
		  requiredDuringSchedulingIgnoredDuringExecution:
		  - labelSelector:
		      matchExpressions:
			  - {key: app, operator: In, values: [nginx,web]}
			topologyKey:'Kubernetes.io/hostname'
		  preferredDuringSchedulingIgnoredDuringExecutio:
		  - weight: 1
	        podAntiAffinityTerm:
			  labelSelector:
			    matchExpressions:
			    - {key:version operator: In, values:[1.12,1.13]}
			  topologyKey:'Kubernetes.io/hostname'

---
#污点
##添加污点
	kubectl taint node <节点名称> <污点名称>=<污点值>：<污点影响>

####污点影响：
	NoExecute: 不将Pod调度到具备该污点的机器上，如果Pod已经在某台机器上运行，且设置了NoExecute污点，则不能容忍该污点的Pod将会被驱逐。
	NoSchedule: 不将Pod调度到具备该污点的机器上，对于已运行的Pod不会驱逐
	PreNoSchedule: 不推荐将Pod调度到具备该污点的机器上

##删除污点
	kubectl taint node <节点名称> <污点名称>-
	
##查看污点
	kubectl describe node <节点名称>
	#查看taint段内容

![](/media//202109/2021-09-30171628891828.png)

---
##示例：开启master调度
	#开启（删除污点）
	kubectl taint node master node-role.Kubernetes.io/master-
	#关闭（添加污点，使Pod不调度到此机上）
	kubectl taint node master node-role.Kubernetes.io/master="":NoSchedule
---
#容忍度
####注意：让Pod调度到具备污点的机器上，则必须要为Pod设置容忍度，让她能接受这些污点。
---
	apiVersion: v1
	kind: pod
	metadata:
	  name: examplepod
	spec:
	  containers:
	  - name: examplepod-container
	     image: busybox
	     imagePullPolicy: IfNotPresent
	     command: ['sh','-c]
	     args: ['echo ""hello world";sleep 36000']
	  tolerations:
	  - key: "restart"
	    operator: "Equal"
		value: "hourly"
		effect: "NoSchedule"
	  - key: "isMaintain"
	    operator: "Equal"
		value: "true"
		effect: "NoExecute"
		tolerationSeconds: 3600
---
##tolerations设置了两个容忍度：
####1、第一个容忍度表示可以容忍restart等于hourly且影响为NoSchedule的污点
####2、第二个容忍度表示可以容忍isMaintain等于true且影响为NoExecute的污点，tolerationSeconds表示可以容忍污点3600s,如果超过这个时间，Pod将会被驱逐
---
#Pod优先级调度
###注意：PriorityClass不属于任何命名空间！优先级超过一亿的数字被系统保留，用于指派给系统组件。

---
##查看PriorityClass
	kubectl get priorityclass

![](/media//202110/2021-10-18170841789325.png)

---
##创建PriorityClass
	vim high-priority.yaml
	===========================================================
	apiVersion: scheduling.k8sio/v1beta1
	kind: PriorityClass
	metadata:
	  name: high-priority
	value: 1000000
	globalDefault: false
	===========================================================
	kubectl apply -f high-priority.yaml

---
##关联PriorityClass
	apiVersion: v1
	kind: pod
	metadata:
	  name: examplepod
	spec:
	  containers:
	  - name: examplepod-container
	     image: busybox
	     imagePullPolicy: IfNotPresent
	     command: ['sh','-c]
	     args: ['echo ""hello world";sleep 36000']
	  priorityClassName: high-priority    #关联优先级

---
#容灾调度（Even Pod Spreading调度规则）（1.16版本及以上）
	apiVersion: apps/v1
	kind: Deployment
	metadata:
	  name: nginx-deployment
	  labels:
	    app: nginx
	spec:
	  topologySpreadConstraints:		#容灾调度，均衡分布
	  - maxSkew: 1		#不均衡数
	    whenUnsatisfiable: DoNotSchedule
		topologyKey: topology.kubernetes.io/zone
	    selector:
	      matchLabels:
	        app: nginx
	    template:
	      metadata:
	        labels:
	          app: nginx
	      spec:
	        containers:
	        - name: nginx
	          image: nginx:1.12.2
	          ports:
	          - containerPort: 80

---
####maxSkew：用于指定Pod在各个Zone上调度时能容忍的最大不均衡数。（值越大，表示能接受的不均衡调度越大，值越小，表示各个ZONE的Pod数量分布越均匀。）

---
##容灾部署：
####1、将一个应用中需要部署在一起的几个Pod用亲和性调度声明捆绑。
####2、选择其中一个Pod，加持Even Pod Spreading调度规则。

![](/media//202110/2021-10-25112237674146.png)