19.kubernetes笔记 Pod资源调度(二) podAffinity、podAntiAffinity Pod亲和与反亲和
概述:
- 先来了解 topology key 字段
pod亲和性调度需要各个相关的pod对象运行于"同一位置"， 而反亲和性调度则要求他们不能运行于"同一位置"，
这里指定“同一位置” 是通过 topologyKey 来定义的，topologyKey 对应的值是 node 上的一个标签名称，比如各别节点zone=A标签，各别节点有zone=B标签，pod affinity topologyKey定义为zone，那么调度pod的时候就会围绕着A拓扑，B拓扑来调度，而相同拓扑下的node就为“同一位置”。 - 顾名思义，topology 就是 拓扑的意思
这里指的是一个 拓扑域，是指一个范围的概念，比如一个 Node、一个机柜、一个机房或者是一个地区（如杭州、上海）等，实际上对应的还是 Node 上的标签。这里的 topologyKey 对应的是 Node 上的标签的 Key（没有Value），可以看出，其实 topologyKey 就是用于筛选 Node 的。通过这种方式，我们就可以将各个 Pod 进行跨集群、跨机房、跨地区的调度了。
文章图片
查看 podAffinity的详细说明
[root@k8s-master Scheduler]# kubectl explain pods.spec.affinity
KIND:Pod
VERSION:v1RESOURCE: affinity 示例1: podAffinity Pod硬亲和
requiredDuringSchedulingIgnoredDuringExecution
[root@k8s-master Scheduler]# cat pod-affinity-required-demo.yaml
apiVersion: apps/v1
kind: Deployment
metadata:
name: redis
spec:
replicas: 1#redis为有状态应用 为了测试只运行1个副本
selector:
matchLabels:
app: redis
ctlr: redis
template:
metadata:
labels:
app: redis
ctlr: redis
spec:
containers:
- name: redis
image: redis:6.0-alpine
---
apiVersion: apps/v1
kind: Deployment
metadata:
name: pod-affinity-required
spec:
replicas: 5
selector:
matchLabels:
app: demoapp
ctlr: pod-affinity-required
template:
metadata:
labels:
app: demoapp
ctlr: pod-affinity-required
spec:
containers:
- name: demoapp
image: ikubernetes/demoapp:v1.0
affinity:
podAffinity: #Pod亲和
requiredDuringSchedulingIgnoredDuringExecution:#硬亲和
- labelSelector:
matchExpressions:
- {key: app, operator: In, values: ["redis"]}#复杂表示达匹配标签 app=reids、ctlr=redis
- {key: ctlr, operator: In, values: ["redis"]}#两个表达式为与关系 同时满足
topologyKey: rack#节点标签 位置标签 rack可以理解为同一个机架上 与labelSelector同样是与关系同时满足[root@k8s-master Scheduler]# kubectl apply -f pod-affinity-required-demo.yaml
deployment.apps/redis unchanged
deployment.apps/pod-affinity-required unchanged[root@k8s-master Scheduler]# kubectl get pod -o wide#节点还没有打上标签pod-affinity挂机
NAMEREADYSTATUSRESTARTSAGEIPNODENOMINATED NODEREADINESS GATES
pod-affinity-required-5dd44f5d45-6vvhd0/1Pending06m7s
pod-affinity-required-5dd44f5d45-c4hzl0/1Pending06m7s
pod-affinity-required-5dd44f5d45-qm6zb0/1Pending06m7s
pod-affinity-required-5dd44f5d45-t4mm50/1Pending06m7s
pod-affinity-required-5dd44f5d45-vs7dg0/1Pending06m7s
redis-55f46d9795-r7pkz1/1Running010m192.168.51.23k8s-node3
- 模拟同一机架不同节点
[root@k8s-master Scheduler]# kubectl label node k8s-node1 rack=foo#为节点1把rack标签
node/k8s-node1 labeled
[root@k8s-master Scheduler]# kubectl label node k8s-node2 rack=bar#为节点2把rack标签
node/k8s-node2 labeled
[root@k8s-master Scheduler]# kubectl label node k8s-node3 rack=baz #为节点3把rack标签
node/k8s-node3 labeled- 硬亲和与redis运行在相同节点 都运行在node3上
[root@k8s-master Scheduler]# kubectl get pod-o wide
NAMEREADYSTATUSRESTARTSAGEIPNODENOMINATED NODEREADINESS GATES
pod-affinity-required-5dd44f5d45-6vvhd1/1Running021m192.168.51.28k8s-node3
pod-affinity-required-5dd44f5d45-c4hzl1/1Running021m192.168.51.26k8s-node3
pod-affinity-required-5dd44f5d45-qm6zb1/1Running021m192.168.51.24k8s-node3
pod-affinity-required-5dd44f5d45-t4mm51/1Running021m192.168.51.25k8s-node3
pod-affinity-required-5dd44f5d45-vs7dg1/1Running021m192.168.51.27k8s-node3
redis-55f46d9795-r7pkz1/1Running025m192.168.51.23k8s-node3 示例2: podAffinity Pod软亲和
preferredDuringSchedulingIgnoredDuringExecution
[root@k8s-master Scheduler]# cat pod-affinity-preferred-demo.yaml
apiVersion: apps/v1
kind: Deployment
metadata:
name: redis-preferred
spec:
replicas: 1
selector:
matchLabels:
app: redis
ctlr: redis-preferred
template:
metadata:
labels:
app: redis
ctlr: redis-preferred
spec:
containers:
- name: redis
image: redis:6.0-alpine
resources:
requests:
cpu: 200m
memory: 512Mi
---
apiVersion: apps/v1
kind: Deployment
metadata:
name: pod-affinity-preferred
spec:
replicas: 4
selector:
matchLabels:
app: demoapp
ctlr: pod-affinity-preferred
template:
metadata:
labels:
app: demoapp
ctlr: pod-affinity-preferred
spec:
containers:
- name: demoapp
image: ikubernetes/demoapp:v1.0
resources:
requests:
cpu: 500m
memory: 100Mi
affinity:
podAffinity:
preferredDuringSchedulingIgnoredDuringExecution:#软亲和以不同权重计算分值重出最终的亲和节点
- weight: 100
podAffinityTerm:
labelSelector:
matchExpressions:
- {key: app, operator: In, values: ["redis"]}
- {key: ctlr, operator: In, values: ["redis-prefered"]}#Pod包含标签为app=redis、ctlr=redis-prefered同时满足
topologyKey: kubernetes.io/hostname#节点位置标签 以不同节点为位置 表示在相同节点权重为100 所有同一节点权重最高
- weight: 50
podAffinityTerm:
labelSelector:
matchExpressions:
- {key: app, operator: In, values: ["redis"]}
- {key: ctlr, operator: In, values: ["redis-prefered"]}
topologyKey: rack#节点标签 位置标签 以机架为位置表示在相同机架权重为50[root@k8s-master Scheduler]# kubectl apply -fpod-affinity-preferred-demo.yaml [root@k8s-master Scheduler]# kubectl get pod -o wide#运行在不同的节点
NAMEREADYSTATUSRESTARTSAGEIPNODENOMINATED NODEREADINESS GATES
pod-affinity-preferred-57d457968f-4lxvq1/1Running05m6s192.168.113.21k8s-node1
pod-affinity-preferred-57d457968f-krb2f1/1Running05m6s192.168.113.20k8s-node1
pod-affinity-preferred-57d457968f-mzckm1/1Running05m6s192.168.12.24k8s-node2
pod-affinity-preferred-57d457968f-v8n8g1/1Running05m6s192.168.51.37k8s-node3
redis-preferred-5d775df679-wtpgs1/1Running05m6s192.168.51.38k8s-node3
示例3: podAntiAffinity 硬反亲和
【19.kubernetes笔记 Pod资源调度(二) podAffinity、podAntiAffinity Pod亲和与反亲和】requiredDuringSchedulingIgnoredDuringExecution
- Deployment 4个副本必须运行在不同的节点上 因为node节点只有3个所有会有个挂起 内部相斥
[root@k8s-master Scheduler]# cat pod-antiaffinity-required-demo.yaml
apiVersion: apps/v1
kind: Deployment
metadata:
name: pod-antiaffinity-required
spec:
replicas: 4#运行4个副本
selector:
matchLabels:
app: demoapp
ctlr: pod-antiaffinity-required
template:
metadata:
labels:
app: demoapp
ctlr: pod-antiaffinity-required
spec:
containers:
- name: demoapp
image: ikubernetes/demoapp:v1.0
affinity:
podAntiAffinity:
requiredDuringSchedulingIgnoredDuringExecution:
- labelSelector:
matchExpressions:
- {key: app, operator: In, values: ["demoapp"]}
- key: ctlr
operator: In
values: ["pod-antiaffinity-required"]#Pod包含标签app=demoapp、ctlr=pod-antiaffinity-required 同时满足
topologyKey: kubernetes.io/hostname#以节点为位置表示每个节点只能运行1个Pod[root@k8s-master Scheduler]# kubectl apply -fpod-antiaffinity-required-demo.yaml [root@k8s-master Scheduler]# kubectl get pod -o wide
NAMEREADYSTATUSRESTARTSAGEIPNODENOMINATED NODEREADINESS GATES
pod-antiaffinity-required-697f7d764d-hgkxj1/1Running05m5s192.168.113.34k8s-node1
pod-antiaffinity-required-697f7d764d-n4zt91/1Running05m5s192.168.12.34k8s-node2
pod-antiaffinity-required-697f7d764d-psqfb1/1Running05m5s192.168.51.53k8s-node3
pod-antiaffinity-required-697f7d764d-q6t7m0/1Pending05m5s#挂起 因为只有3个node节点 推荐阅读
- EffectiveObjective-C2.0|EffectiveObjective-C2.0 笔记 - 第二部分
- Android中的AES加密-下
- 【读书笔记】贝叶斯原理
- 【韩语学习】（韩语随堂笔记整理）
- 人性的弱点-笔记
- 读书笔记:博登海默法理学|读书笔记:博登海默法理学 —— 正义的探索（1）
- D034+3组苏曼＋《写作这回事》读书笔记
- 《自我的追寻》读书笔记3
- 最有效的时间管理工具（赢效率手册和总结笔记）
- 机器学习|机器学习 Andrew Ng《Machine Learning》课程笔记1