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k8s调度器是允许自定义的
1.k8s的调度算法会从众多node选出适用的调度算法
2.预选过程是排除那些不符合Pod运行的环境
3.优选节点然后绑定
也可以自己进行调度，如ssd，GPU等
思路：加上标签就可以
调度器：
预选策略：
CheckNodeCondition：先去检查node，磁盘是否正常
GeneralPredicates：通用预选策略
Hostname：检查Pod对象是否定义了Pod，spec，hostname
PodFirstHostPorts：Pods.spec.containers.ports.hostPort
MatchNodeSelector:Pods.spec.nodeSelector
PodFitsResources:检查Pod的需求资源是否节点可以满足
NoDiskConflict:检查存储卷是否满足需求
PodToleratesNodeTainsts：检查Pod上spec。tolerations可以容忍的五点是否完全包含节点上的污点。
PodToleratesNodeNoExecuteTaints:是否可以接受NoExecute污点
CheckNodeLabelPresence：检查标签的存在性
CheckServiceAffinity：将相同角色的pod分配到一块
参考：
https://github.com/kubernetes/kubernetes/tree/master/pkg/scheduler/algorithm/priorities
优先函数：
LeastRequested：
（cpu（（capacity-sum（requested））10/capacity）+memory（（capacity-sum（requested））*10/capacity ））/2
BalancedResourceAllocation:
CPU和内存资源占用率相近的胜出；
NodePreferAvoidPods:
节点注解信息“scheduler.alpha.kubernetes.io/preferAvoidPods”
TaintToleration: 将Pod对象的spec.tolerations列表项进行匹配检查，匹配条越多，得分越低
SeletorSpereading
InterPodAffinity
MostRequested
NodeLabel
ImageLocality 根据满足当前Pod对象需求的已有镜像的体积大小之和
K8s的高级调度方式
3种影响调度方式：
节点选择器：nodeSelector，nodeName
节点亲和调度：nodeAffinity
第一种方式：节点选择器 nodeSelector，nodeName
实验：
[root@master schedule]# cat pod-demo.yaml
apiVersion: v1
kind: Pod
metadata:
name: pod-demo
labels:
app: myapp
tier: frontend
spec:
containers:
- name: myapp
image: ikubernetes/myapp:v1
nodeSelector:
desktype: ssd #标签选择器，选择标签是desktype: ssd的nodes
将node1设置一个标签
kubectl label nodes node2 desktype=ssd
[root@master schedule]# kubectl get nodes --show-labels
NAME STATUS ROLES AGE VERSION LABELS
master Ready master 13d v1.11.2 beta.kubernetes.io/arch=amd64,beta.kubernetes.io/os=linux,kubernetes.io/hostname=master,node-role.kubernetes.io/master=
node1 Ready <none> 13d v1.11.2 beta.kubernetes.io/arch=amd64,beta.kubernetes.io/os=linux,disktype=ssh,kubernetes.io/hostname=node1
node2 Ready <none> 13d v1.11.2 beta.kubernetes.io/arch=amd64,beta.kubernetes.io/os=linux,desktype=ssd,kubernetes.io/hostname=node2,release=ssd
[root@master schedule]# kubectl get nodes --show-labels
NAME STATUS ROLES AGE VERSION LABELS
master Ready master 13d v1.11.2 beta.kubernetes.io/arch=amd64,beta.kubernetes.io/os=linux,kubernetes.io/hostname=master,node-role.kubernetes.io/master=
node1 Ready <none> 13d v1.11.2 beta.kubernetes.io/arch=amd64,beta.kubernetes.io/os=linux,disktype=ssh,kubernetes.io/hostname=node1
node2 Ready <none> 13d v1.11.2 beta.kubernetes.io/arch=amd64,beta.kubernetes.io/os=linux,desktype=ssd,kubernetes.io/hostname=node2,release=ssd
如果节点没有这个标签，那么创建的时候是无法成功的，因为预选的时候就不成功。
第二种方式：节点亲和调度：nodeAffinity
1.硬亲和性
2.软亲和性
[root@master schedule]# cat pod-nodeaffinty.yaml
apiVersion: v1
kind: Pod
metadata:
name: pod-node-affinity-demo
labels:
app: myapp
tier: frontend
spec:
containers:
- name: myapp
image: ikubernetes/myapp:v1
affinity:
nodeAffinity:
requiredDuringSchedulingIgnoredDuringExecution:
nodeSelectorTerms:
- matchExpressions:
- key: zone
operator: In
values:
- foo
- bar
[root@master schedule]# kubectl apply -f pod-nodeaffinty.yaml
pod/pod-node-affinity-demo created
[root@master schedule]# kubectl get pods
NAME READY STATUS RESTARTS AGE
pod-node-affinity-demo 0/1 Pending 0 1m
[root@master schedule]# kubectl delete -f pod-nodeaffinty.yaml
pod "pod-node-affinity-demo" deleted
[root@master schedule]# cat pod-nodeaffinty-demo-2.yaml
apiVersion: v1
kind: Pod
metadata:
name: pod-node-affinity-demo
labels:
app: myapp
tier: frontend
spec:
containers:
- name: myapp
image: ikubernetes/myapp:v1
affinity:
nodeAffinity:
preferredDuringSchedulingIgnoredDuringExecution:
- preference:
matchExpressions:
- key: zone
operator: In
values:
- foo
- bar
weight: 60
[root@master schedule]# kubectl apply -f pod-nodeaffinty-demo-2.yaml
pod/pod-node-affinity-demo created
[root@master schedule]# kubectl get pods
NAME READY STATUS RESTARTS AGE
pod-node-affinity-demo 1/1 Running 0 50s
[root@master schedule]# kubectl describe pod pod-node-affinity-demo
Name: pod-node-affinity-demo
Namespace: default
Priority: 0
PriorityClassName: <none>
Node: node02/192.168.1.67
Start Time: Wed, 22 Aug 2018 09:21:06 +0800
Labels: app=myapp
tier=frontend
Annotations: cni.projectcalico.org/podIP=10.244.2.4/32
kubectl.kubernetes.io/last-applied-configuration={"apiVersion":"v1","kind":"Pod","metadata":{"annotations":{},"labels":{"app":"myapp","tier":"frontend"},"name":"p
od-node-affinity-demo","namespace":"de...Status: Running
IP: 10.244.2.4
Containers:
myapp:
Container ID: docker://8257c32da71b33f7ef8e6a7907b6ac11d5232a3d7b5f1be84541868bddb17adf
Image: ikubernetes/myapp:v1
Image ID: docker-pullable://ikubernetes/myapp@sha256:9c3dc30b5219788b2b8a4b065f548b922a34479577befb54b03330999d30d513
Port: <none>
Host Port: <none>
State: Running
Started: Wed, 22 Aug 2018 09:21:09 +0800
Ready: True
Restart Count: 0
Environment: <none>
Mounts:
/var/run/secrets/kubernetes.io/serviceaccount from default-token-4xzt8 (ro)
Conditions:
Type Status
Initialized True
Ready True
ContainersReady True
PodScheduled True
Volumes:
default-token-4xzt8:
Type: Secret (a volume populated by a Secret)
SecretName: default-token-4xzt8
Optional: false
QoS Class: BestEffort
Node-Selectors: <none>
Tolerations: node.kubernetes.io/not-ready:NoExecute for 300s
node.kubernetes.io/unreachable:NoExecute for 300s
Events:
Type Reason Age From Message
---- ------ ---- ---- -------
Normal Scheduled 1m default-scheduler Successfully assigned default/pod-node-affinity-demo to node02
Normal Pulled 1m kubelet, node02 Container image "ikubernetes/myapp:v1" already present on machine
Normal Created 1m kubelet, node02 Created container
Normal Started 1m kubelet, node02 Started container
[root@master schedule]# kubectl delete -f pod-nodeaffinty-demo-2.yaml
pod "pod-node-affinity-demo" deleted
#pod2 亲和到pod1
[root@master schedule]# cat pod-required-affinity-demo.yaml
apiVersion: v1
kind: Pod
metadata:
name: pod-first
labels:
app: myapp
tier: frontend
spec:
containers:
- name: myapp
image: ikubernetes/myapp:v1
---
apiVersion: v1
kind: Pod
metadata:
name: pod-second
labels:
app: backend
tier: db
spec:
containers:
- name: busybox
image: busybox:latest
imagePullPolicy: IfNotPresent
command: ["sh","-c","sleep 3600"]
affinity:
podAffinity:
requiredDuringSchedulingIgnoredDuringExecution:
- labelSelector:
matchExpressions:
- {key: app, operator: In, values: ["myapp"]}
topologyKey: kubernetes.io/hostname
[root@master schedule]# kubectl apply -f pod-required-affinity-demo.yaml
pod/pod-first created
pod/pod-second created
[root@master schedule]# kubectl get pods -o wide
NAME READY STATUS RESTARTS AGE IP NODE
pod-first 1/1 Running 0 1m 10.244.2.5 node02
pod-second 1/1 Running 0 1m 10.244.2.6 node02
#不亲和
[root@master schedule]# cp pod-required-affinity-demo.yaml pod-required-anti-demo.yaml
[root@master schedule]# vim pod-required-anti-demo.yaml
apiVersion: v1
kind: Pod
metadata:
name: pod-first
labels:
app: myapp
tier: frontend
spec:
containers:
- name: myapp
image: ikubernetes/myapp:v1
---
apiVersion: v1
kind: Pod
metadata:
name: pod-second
labels:
app: backend
tier: db
spec:
containers:
- name: busybox
image: busybox:latest
imagePullPolicy: IfNotPresent
command: ["sh","-c","sleep 3600"]
affinity:
podAntiAffinity:
requiredDuringSchedulingIgnoredDuringExecution:
- labelSelector:
matchExpressions:
- {key: app, operator: In, values: ["myapp"]}
topologyKey: kubernetes.io/hostname
[root@master schedule]# kubectl apply -f pod-required-anti-demo.yaml
pod/pod-first created
pod/pod-second created
[root@master schedule]# kubectl get pods -o wide
NAME READY STATUS RESTARTS AGE IP NODE
pod-first 1/1 Running 0 39s 10.244.3.5 node01
pod-second 1/1 Running 0 39s 10.244.2.7 node02
[root@master schedule]# kubectl delete -f pod-required-anti-demo.yaml
pod "pod-first" deleted
pod "pod-second" deleted
#同一标签不亲和调度
[root@master schedule]# kubectl get nodes --show-labels
NAME STATUS ROLES AGE VERSION LABELS
master Ready master 7d v1.11.2 beta.kubernetes.io/arch=amd64,beta.kubernetes.io/os=linux,kubernetes.io/hostname=master,node-role.kubernetes.io/master=
node01 Ready <none> 7d v1.11.2 beta.kubernetes.io/arch=amd64,beta.kubernetes.io/os=linux,kubernetes.io/hostname=node01
node02 Ready <none> 7d v1.11.2 beta.kubernetes.io/arch=amd64,beta.kubernetes.io/os=linux,disktype=harddisk,kubernetes.io/hostname=node02
[root@master schedule]# kubectl label nodes node01 zone=foo
node/node01 labeled
[root@master schedule]# kubectl label nodes node02 zone=foo
node/node02 labeled
[root@master schedule]# vim pod-required-anti-demo.yaml
apiVersion: v1
kind: Pod
metadata:
name: pod-first
labels:
app: myapp
tier: frontend
spec:
containers:
- name: myapp
image: ikubernetes/myapp:v1
---
apiVersion: v1
kind: Pod
metadata:
name: pod-second
labels:
app: backend
tier: db
spec:
containers:
- name: busybox
image: busybox:latest
imagePullPolicy: IfNotPresent
command: ["sh","-c","sleep 3600"]
affinity:
podAntiAffinity:
requiredDuringSchedulingIgnoredDuringExecution:
- labelSelector:
matchExpressions:
- {key: app, operator: In, values: ["myapp"]}
topologyKey: zone
[root@master schedule]# kubectl apply -f pod-required-anti-demo.yaml
pod/pod-first created
pod/pod-second created
[root@master schedule]# kubectl get pods -o wide
NAME READY STATUS RESTARTS AGE IP NODE
pod-first 1/1 Running 0 23s 10.244.2.8 node02
pod-second 0/1 Pending 0 23s <none> <none>
[root@master schedule]# kubectl delete -f pod-required-anti-demo.yaml
pod "pod-first" deleted
pod "pod-second" deleted污点调度
[root@master schedule]# kubectl taint node node01 node-type=producction:NoSchedule
node/node01 tainted
[root@master schedule]# vim deploy-demo.yaml
apiVersion: v1
kind: Service
metadata:
name: myapp
namespace: default
spec:
selector:
app: myapp
release: canary
ports:
- name: http
targetPort: 80
port: 80
---
apiVersion: apps/v1
kind: Deployment
metadata:
name: myapp-deploy
namespace: default
spec:
replicas: 3
selector:
matchLabels:
app: myapp
release: canary
template:
metadata:
labels:
app: myapp
release: canary
spec:
containers:
- name: myapp
image: ikubernetes/myapp:v2
ports:
- name: http
containerPort: 80
[root@master schedule]# kubectl apply -f deploy-demo.yaml
service/myapp created
deployment.apps/myapp-deploy created
[root@master schedule]# kubectl get pods -o wide
NAME READY STATUS RESTARTS AGE IP NODE
myapp-deploy-67f6f6b4dc-drl57 1/1 Running 0 10s 10.244.2.9 node02
myapp-deploy-67f6f6b4dc-fbbgx 1/1 Running 0 10s 10.244.2.11 node02
myapp-deploy-67f6f6b4dc-gtl52 1/1 Running 0 10s 10.244.2.10 node02
[root@master schedule]# kubectl taint node node02 node-type=dev:NoExecute
node/node02 tainted
[root@master schedule]# kubectl get pods -o wide
NAME READY STATUS RESTARTS AGE IP NODE
myapp-deploy-67f6f6b4dc-6hxj8 0/1 Pending 0 6s <none> <none>
myapp-deploy-67f6f6b4dc-drl57 1/1 Terminating 0 1m 10.244.2.9 node02
myapp-deploy-67f6f6b4dc-fbbgx 0/1 Terminating 0 1m <none> node02
myapp-deploy-67f6f6b4dc-gtl52 0/1 Terminating 0 1m <none> node02
myapp-deploy-67f6f6b4dc-lwz94 0/1 Pending 0 6s <none> <none>
myapp-deploy-67f6f6b4dc-mtkgg 0/1 Pending 0 6s <none> <none>
[root@master schedule]# cat deploy-demo.yaml
apiVersion: v1
kind: Service
metadata:
name: myapp
namespace: default
spec:
selector:
app: myapp
release: canary
ports:
- name: http
targetPort: 80
port: 80
---
apiVersion: apps/v1
kind: Deployment
metadata:
name: myapp-deploy
namespace: default
spec:
replicas: 3
selector:
matchLabels:
app: myapp
release: canary
template:
metadata:
labels:
app: myapp
release: canary
spec:
containers:
- name: myapp
image: ikubernetes/myapp:v2
ports:
- name: http
containerPort: 80
tolerations:
- key: "node-type"
operator: "Equal"
value: "producction"
effect: "NoSchedule"
[root@master schedule]# kubectl apply -f deploy-demo.yaml
service/myapp unchanged
deployment.apps/myapp-deploy configured
[root@master schedule]# kubectl get pods -o wide
NAME READY STATUS RESTARTS AGE IP NODE
myapp-deploy-698b44b9d7-2bjkc 1/1 Running 0 37s 10.244.3.7 node01
myapp-deploy-698b44b9d7-2ctvc 1/1 Running 0 43s 10.244.3.6 node01
myapp-deploy-698b44b9d7-htdxx 1/1 Running 0 34s 10.244.3.8 node01
[root@master schedule]# cat deploy-demo.yaml
apiVersion: v1
kind: Service
metadata:
name: myapp
namespace: default
spec:
selector:
app: myapp
release: canary
ports:
- name: http
targetPort: 80
port: 80
---
apiVersion: apps/v1
kind: Deployment
metadata:
name: myapp-deploy
namespace: default
spec:
replicas: 3
selector:
matchLabels:
app: myapp
release: canary
template:
metadata:
labels:
app: myapp
release: canary
spec:
containers:
- name: myapp
image: ikubernetes/myapp:v2
ports:
- name: http
containerPort: 80
tolerations:
- key: "node-type"
operator: "Exists"
value: ""
effect: "NoSchedule"
[root@master schedule]# kubectl apply -f deploy-demo.yaml
service/myapp unchanged
deployment.apps/myapp-deploy configured
[root@master schedule]# kubectl get pods -o wide
NAME READY STATUS RESTARTS AGE IP NODE
myapp-deploy-559f559bcc-8lp4d 1/1 Running 0 21s 10.244.3.10 node01
myapp-deploy-559f559bcc-qcnz9 1/1 Running 0 17s 10.244.3.11 node01
myapp-deploy-559f559bcc-vwdzb 1/1 Running 0 24s 10.244.3.9 node01
[root@master schedule]# cat deploy-demo.yaml
apiVersion: v1
kind: Service
metadata:
name: myapp
namespace: default
spec:
selector:
app: myapp
release: canary
ports:
- name: http
targetPort: 80
port: 80
---
apiVersion: apps/v1
kind: Deployment
metadata:
name: myapp-deploy
namespace: default
spec:
replicas: 3
selector:
matchLabels:
app: myapp
release: canary
template:
metadata:
labels:
app: myapp
release: canary
spec:
containers:
- name: myapp
image: ikubernetes/myapp:v2
ports:
- name: http
containerPort: 80
tolerations:
- key: "node-type"
operator: "Exists"
value: ""
effect: ""
[root@master schedule]# kubectl apply -f deploy-demo.yaml
service/myapp unchanged
deployment.apps/myapp-deploy configured
[root@master schedule]# kubectl get pods -o wide
NAME READY STATUS RESTARTS AGE IP NODE
myapp-deploy-5d9c6985f5-7mgtd 1/1 Running 0 51s 10.244.2.13 node02
myapp-deploy-5d9c6985f5-b78h8 1/1 Running 0 46s 10.244.3.12 node01
myapp-deploy-5d9c6985f5-lljrz 1/1 Running 0 55s 10.244.2.12 node02