kubernetes服务部署中常用控制器
介绍
kubernetes 提供了多种控制器，控制器能够对pod 进行部署、滚动升级、回滚、灰度发布、自愈
先了解下控制
控制器分析
- 部署nginx
kubectl run niginx21--imang=nginx
# 查看描述
kubect describe pod niginx21
nginx21 上级控制器为： ReplicaSet/nginx21-54bbb4b57
- 查看上级控制器
kubectl describe ReplicaSet/nginx21-54bbb4b57
ReplicaSet/nginx21-54bbb4b57上级控制器 Deployment/nginx21
- 上级控制器
kubectl describe Deployment/nginx21
层层查找控制器，顶层是 Deploument。kubernetes 节点升级、回滚、自愈等最终由顶级控制器控制
部署一个单pod
apiVersion: v1
kind: Pod
metadata:
name: pod-22
labels:
pod: pod-label
spec:
containers:
- image: nginx
name: ng-pod
status: {}
- 查看
kubectl describe pod pod-22
单个pod 没有任何控制控制
- 测试
# 扩容 nginx-21
[root@guanzc-130 kubernetes]# kubectl scale --replicas=3 deployment/nginx21
deployment.apps/nginx21 scaled
# 查看
[root@guanzc-130 kubernetes]# kubectl get pod
NAME READY STATUS RESTARTS AGE
nginx01-7fbfd5976c-qb2fs 1/1 Running 2 2d10h
nginx21-54bbb4b57-bpdnc 1/1 Running 0 14m
nginx21-54bbb4b57-brcps 1/1 Running 0 14m
nginx21-54bbb4b57-v6rv2 1/1 Running 0 50m
pod-20 1/1 Running 1 37h
pod-21 1/1 Running 1 37h
pod-22 1/1 Running 1 37h
# 删除pod-22
[root@guanzc-130 kubernetes]# kubectl delete pod pod-22
pod "pod-22" deleted
# 删除nginx-21
[root@guanzc-130 kubernetes]# kubectl delete pod pod-22
pod "pod-22" deleted
[root@guanzc-130 kubernetes]# kubectl delete pod nginx21-54bbb4b57-bpdnc
pod "nginx21-54bbb4b57-bpdnc" deleted
[root@guanzc-131 ~]# kubectl get pod
NAME READY STATUS RESTARTS AGE
nginx01-7fbfd5976c-qb2fs 1/1 Running 2 2d10h
nginx21-54bbb4b57-brcps 1/1 Running 0 17m
nginx21-54bbb4b57-qg2gf 0/1 ContainerCreating 0 13s
nginx21-54bbb4b57-v6rv2 1/1 Running 0 54m
pod-20 1/1 Running 1 37h
pod-21 1/1 Running 1 37h
[root@guanzc-131 ~]#
[root@guanzc-130 kubernetes]# kubectl get pod
NAME READY STATUS RESTARTS AGE
nginx01-7fbfd5976c-qb2fs 1/1 Running 2 2d10h
nginx21-54bbb4b57-brcps 1/1 Running 0 18m
nginx21-54bbb4b57-qg2gf 1/1 Running 0 37s
nginx21-54bbb4b57-v6rv2 1/1 Running 0 55m
pod-20 1/1 Running 1 37h
pod-21 1/1 Running 1 37h
[root@guanzc-130 kubernetes]#
单pod 永远被删除，受控制器管理，删除后自愈，保证副本为3
- 父子控制优先级
pod 信息
- 修改副本数
kubectl edit
- 查看结果
副本数量开始1个，最终是3个，副本总数最终受 deployment 控制
小结
- 由控制器控制的pod， 有自愈能力，pod 挂掉还是删除pod，总能保证节点副本数与配置相同(副本由ReplicaSet保证)
- 单pod不受任何控制器控制，一旦pod 挂掉，不会再恢复。不建议使用单pod 部署应用
- 副本优先级受 Deployment 控制
常用控制器
-
Deployment
自愈、滚动更新、副本、灰度发布、回滚等
-
ReplicaSet
ReplicaSet 常用于pod 自愈，官方建议用 Deployment替代
-
ReplicationController
功能与ReplicaSet 类似，官方建议用 Deployment替代
-
StatefulSet
有状态副本集
-
DaemonSet
daemon方式，每个节点都有
-
CronJob
定时任务
-
Jobs
任务
-
Garbage Collection
垃圾回收
-
TTL Controller for Finished Resources
time to live；自动清理Job
使用ReplicaSet 部署应用
- 获取部署应用yaml
kubectl get all
#获取yaml,
kubectl get replicaset.apps/nginx01-7fbfd5976c -o yaml
- 应用部署文件
nginx-rs.yaml
apiVersion: apps/v1
kind: ReplicaSet
metadata:
name: rs-pod
spec:
replicas: 3
selector:
matchLabels:
pod-label: nginx-rs-test
template:
metadata:
labels:
pod-label: nginx-rs-test
spec:
containers:
- image: nginx
imagePullPolicy: Always
name: nginx-rs-01
- 部署
kubectl apply -f nginx-rs.yaml
# 查看
kubectl get pod
使用 kind: ReplicaSet 部署，只产生了 replicaset.apps 控制器
执行删除操作，pod 会被删除，会自动创建，保持配置的3个副本
replicaset 能保持副本数，但是无法进行滚动升级
滚动升级
- replicaset控制pod 升级
修改 nginx-rs,yaml
apiVersion: apps/v1
kind: ReplicaSet
metadata:
name: rs-pod
spec:
replicas: 3
selector:
matchLabels:
pod-label: nginx-rs-test
template:
metadata:
labels:
pod-label: nginx-rs-test
spec:
containers:
- image: tomcat:8
imagePullPolicy: Always
name: nginx-rs-01
- 部署查看
kubectl apply -f nginx-rs.yaml
镜像修改为tomcat，升级后镜像为 nginx，并未生效。
以deployment 部署，滚动升级
- 配置文件
apiVersion: apps/v1
kind: Deployment
metadata:
labels:
run: nginx01
name: nginx01
spec:
replicas: 3
selector:
matchLabels:
run: nginxhh
template:
metadata:
creationTimestamp: null
labels:
run: nginxhh
spec:
containers:
- image: nginx
name: nginxhh
status: {}
- 升级测试
将镜像修改为 tomcat:8
kubectl apply -f ngnix-deploy.yml
# 查看
kubectl get pod
最终完成了升级