K8s-控制器

一 为什么使用控制器

pod控制器

作用：1.pod类型资源删除，不会重建
           2.控制器可以帮助用户监控，并保证节点上运行定义好的pod副本数
           3.pod超过或低于用户期望，控制器会创建、删除pod副本数量

控制器类型：

1. RS控制器:按照用户期望的副本数量，创建pod, 用户写yaml，定义RS控制器，去定义pod模板，pod按照这个模板去运行
2. deployment控制器
3. DaemonSet

二 详解rs控制器原理

RS控制器原理：副本数保障、标签选择器

2.1 创建RS控制器

[root@k8s-master ~]# cat rs-nginx.yml 
apiVersion: apps/v1
kind: ReplicaSet
metadata:name: nginx-rsnamespace: lxyspec:replicas: 3selector:matchLabels:app: nginxtemplate:metadata:name: nginx-podlabels:app: nginxspec:containers:- name: nginx-containersimage: nginx:1.14.0imagePullPolicy: IfNotPresentports:- name: httpcontainerPort: 80

kubectl create -f rs-nginx.yml 
kubectl -n lxy get rs -owide
kubectl -n lxy get pods -l app=nginx -owide

 

2.2 删除Pod,查看rs如何保障副本数 

删掉一个pod,但是会马上创建一个

2.3 pod和rs关系 

kubectl -n lxy describe rs nginx-rs 

2.4 修改RS控制器

1.对yaml修改副本数，修改资源配置：kubectl apply -f rs-nginx.yml

2.编辑RS控制器：kubectl -n lxy edit rs nginx-rs  (有些是无法修改)

三 Deploy控制器与弹性扩缩容

kubectl scale --help

kubectl -n lxy scale --replicas=X rs nginx-rs 

root@k8s-master ~]# kubectl -n lxy get pods -owide
NAME             READY   STATUS    RESTARTS   AGE     IP            NODE         NOMINATED NODE   READINESS GATES
nginx-2          1/1     Running   2          5d17h   10.2.20.143   k8s-node13   <none>           <none>
nginx-rs-2zhzn   1/1     Running   0          7h25m   10.2.231.96   k8s-node12   <none>           <none>
nginx-rs-7p64w   1/1     Running   0          7h25m   10.2.20.146   k8s-node13   <none>           <none>
[root@k8s-master ~]# kubectl -n lxy scale --replicas=4 rs nginx-rs 
replicaset.apps/nginx-rs scaled
[root@k8s-master ~]# kubectl -n lxy get pods -owide
NAME             READY   STATUS    RESTARTS   AGE     IP            NODE         NOMINATED NODE   READINESS GATES
nginx-2          1/1     Running   2          5d17h   10.2.20.143   k8s-node13   <none>           <none>
nginx-rs-2zhzn   1/1     Running   0          7h34m   10.2.231.96   k8s-node12   <none>           <none>
nginx-rs-7p64w   1/1     Running   0          7h34m   10.2.20.146   k8s-node13   <none>           <none>
nginx-rs-8jf8p   1/1     Running   0          4s      10.2.20.150   k8s-node13   <none>           <none>
nginx-rs-k9dvr   1/1     Running   0          4s      10.2.20.149   k8s-node13   <none>           <none>
[root@k8s-master ~]# kubectl -n lxy scale --replicas=2 rs nginx-rs 
replicaset.apps/nginx-rs scaled
[root@k8s-master ~]# kubectl -n lxy get pods -owide
NAME             READY   STATUS        RESTARTS   AGE     IP            NODE         NOMINATED NODE   READINESS GATES
nginx-2          1/1     Running       2          5d17h   10.2.20.143   k8s-node13   <none>           <none>
nginx-rs-2zhzn   1/1     Running       0          7h34m   10.2.231.96   k8s-node12   <none>           <none>
nginx-rs-7p64w   1/1     Running       0          7h34m   10.2.20.146   k8s-node13   <none>           <none>
nginx-rs-8jf8p   0/1     Terminating   0          12s     10.2.20.150   k8s-node13   <none>           <none>
nginx-rs-k9dvr   0/1     Terminating   0          12s     10.2.20.149   k8s-node13   <none>           <none>

获取当前rs资源的Yaml: kubectl -n lxy get rs nginx-rs -oyaml

四 Deploy与rs原理

Deployments | Kubernetes

kubectl -n kube-system get deploy coredns -o yaml

[root@k8s-master ~]# cat deployment.yaml 
apiVersion: apps/v1
kind: Deployment
metadata:name: nginx-deploymentnamespace: lxy
spec:replicas: 2selector:matchLabels:app: nginxtemplate:metadata:labels:app: nginxspec:containers:- name: nginximage: nginx:1.14.2ports:- containerPort: 80resources:limits:cpu: 100mmemory: 200Mirequests:cpu: 100mmemory: 200Mi

[root@k8s-master ~]# kubectl get deployments.apps -owide -n lxy
NAME               READY   UP-TO-DATE   AVAILABLE   AGE    CONTAINERS   IMAGES         SELECTOR
nginx-deployment   2/2     2            2           110s   nginx        nginx:1.14.2   app=nginx
[root@k8s-master ~]# kubectl get rs -n lxy
NAME                          DESIRED   CURRENT   READY   AGE
nginx-deployment-58df99679c   2         2         2       115s
nginx-rs                      2         2         2       8h
[root@k8s-master ~]# kubectl get pods -l app=nginx -n lxy
NAME                                READY   STATUS    RESTARTS   AGE
nginx-deployment-58df99679c-tqxps   1/1     Running   0          119s
nginx-deployment-58df99679c-zhvcj   1/1     Running   0          119s
nginx-rs-2zhzn                      1/1     Running   0          8h
nginx-rs-7p64w                      1/1     Running   0          8h

pod和rs和deployment关系
kubectl describe pods nginx-deployment-AAA-XX
kubectl describe rs nginx-deployment-AAA 

五 滚动更新详解原理

蓝绿更新：起一个新的Pod+删除一个旧pod,接替就是滚动更新

六 更新镜像版本其他玩法

1.kubectl edit rs资源
2.kubectl  scale  --replicas=xxx   rs  rs名
3.edit 编辑deployment资源
4.deployment提供了 修改镜像版本 参数   kubectl  set image

七 版本更新与回滚详解

因为rs控制器还在，数据还在 kubectl get rs -owide -w / kubectl get rs -owide -n lxy

#查看版本是1.14.2
kubectl get deployments.apps -n lxy -owide
#修改版本为1.14.1
kubectl -n lxy set image deployment nginx-deployment nginx=nginx:1.14.1
#这时候在查看是1.14.1，使用命令回归后，恢复成1.14.2
kubectl rollout undo deployment nginx-deployment -n lxy

八 详解版本记录号玩法

1.kubectl create -f last-deploy-nginx.yml --record    ----创建的时候，记录版本号

2.查看deploy版本信息

kubectl rollout history deployment  last-nginx-deployment 

kubectl rollout status  deployment  last-nginx-deployment 

kubectl rollout history deployment last-nginx-deployment --revision=2（指定那个版本的镜像信息）

3.指定回滚到哪个版本

kubectl rollout undo  deployment last-nginx-deployment --to-revision=1