ReplicaSet&Deployment

replica

创建pod的副本

不会以kubectl delete pod podName的方式而被删除。必须通过replicaset相关命令进行操作。

创建replicaset模板文件

apiVersion: apps/v1
kind: ReplicaSet
metadata:
spec:
- selector
  - matchLables: :wq必须和template中metadata里面的label一样
- replicas:确定replica的个数。（删除pod后自动添加新的pod。当pod数为replicas指定个数时，不能创建新pod）
- template：里面是pod的定义(metadata和spec的部分)

example

apiVersion: apps/v1
kind: ReplicaSet
metadata:
  name: myapp-replicaset
  labels:
    app: myapp
spec:
  selector:
    matchLabels:
      env: production
  replicas: 3
  template:
    metadata:
      name: nginx-2
      labels:
        env: production
    spec:
      containers:
        - name: nginx
          image: nginx

replicaset的selector的matchLabels必须和template的labels下面的内容一致。和replicaset自身labels无关。

常用指令

创建replicaset

kubectl create -f replicaset definition.yaml
查看当前replicaset的个数（注意不是pod的个数）

kubectl get replicaset
查看当前replicaset的详细信息(replicaSetName指的是具体的replicaset的名字，可通过kubectl get replicaset获得)

kubectl describe replicaset replicaSetName
get pods 查看具体pod信息
查看创建replicaset所需要的属性信息(replicaSetName指的是具体的replicaset的名字)

kubectl explain replicaset replicaSetName
删除replicaset

kubectl delete replicaset replicasetName
- --all：删除所有的replicaset
  
  kubectl delete replicaset --all

编辑指定的replicaset：默认以vim打开并修改replicaset的配置

kubectl edit replicaset replicasetName

然后删除原有的旧pods kubectl delete pods --all，replicaset会自动创建新pods
scaled命令修改当前replicaset的replica的个数

kubectl scale replicaset replicaSetName --replicas=2

Deployment

目的：为Pods和ReplicaSet提供声明式的更新

创建deployment模板

和replicaset模板很像，区别是kind为Deployment

apiVersion: apps/v1
kind: Deployment
metadata:
  name: myapp-deployment
  labels:
    tier: frontend
    app: nginx
spec:
  selector:
    matchLabels: #必须和template.metadata.lables一致
      app: myapp 
  replicas: 3
  template:
    metadata:
      name: nginx-2 #the name of pod
      labels:
        app: myapp
    spec:
      containers: #以list形式来定义pod里面的container
        - name: nginx #the name of container in the pod
          image: nginx

command

create deployment

kubectl create -f deployment.yaml
查看当前deployment

kubectl get deployment
查看某一个deployment的具体信息

kubectl describe deployment deploymentName

Update&Rollout

Rollout

追踪deployment的变化并能是我们能够回归到前一个版本

查看rollout的状态

kubectl rollout status deployment/myapp-deployment (myapp-deployment是deployment的name)
show reversion and history of our deployment

kubectl rollout history deployment/myapp-deployment

Deployment策略：

Recreate 和 RollingUpdate (StrategyType)的区别

Recreate策略：先scale down replicaset到0，然后再重新scale up replicaset到预定个数(not default)
RollingUpdate(滚动更新)策略：每次同时地scale up replicaset 和scale down replicaset(defalult)

Rollback (回退)

在新版本的pod里发现了问题，要返回到上一个版本

Run the kubectl rollout undo command followed by the name of the deployment

kubectl rollout undo deployment/myapp-deployment

Summarize Commands

Create deployment

kubectl create -f deployment-definition.yml
Get 获取所有deployment的信息

kubectl get deployments
Update 单独升级image（会导致deployment的定义文件中有不同的image配置）(推荐kubectl edit deployment myapp-deployment)

kubectl set image deployment/myapp-deployment nginx=nginx:1.9.1
回滚的状态 rollout status

kubectl rollout status deployment/myapp-deployment
回滚的history

kubectl rollout history deployment/myapp-deployment
Rollback

kubectl rollout undo deployment/myapp-deployment

example

1,先create deployment （--record：的意义是记录操作的历史记录）

kubectl create -f deployment-defination.yaml --record

2,获取deployment的名字

kubectl get deployment

root@master01 work]# kubectl get deployment
NAME               READY   UP-TO-DATE   AVAILABLE   AGE
myapp-deployment   3/3     3            3           12s

3,使用 kubectl edit deployment myapp-deployment修改image版本为 nginx:1.18

kubectl edit deployment myapp-deployment --record

4,使用kubectl rollout status deployment myapp-deployment查看rollout状态

[root@master01 work]# kubectl rollout status deployment myapp-deployment
Waiting for deployment "myapp-deployment" rollout to finish: 2 out of 3 new replicas have been updated...
Waiting for deployment "myapp-deployment" rollout to finish: 2 out of 3 new replicas have been updated...
Waiting for deployment "myapp-deployment" rollout to finish: 2 out of 3 new replicas have been updated...
Waiting for deployment "myapp-deployment" rollout to finish: 1 old replicas are pending termination...
Waiting for deployment "myapp-deployment" rollout to finish: 1 old replicas are pending termination...
deployment "myapp-deployment" successfully rolled out

5,使用kubectl rollout history deployment myapp-deployment

[root@master01 work]# kubectl rollout history deployment myapp-deployment
deployment.apps/myapp-deployment 
REVISION  CHANGE-CAUSE
1         kubectl create --filename=deployment-defination.yaml --record=true
2         kubectl edit deployment/myapp-deployment --record=true

6,使用kubectl set image deployment <your_deployment_name> containerName=<image_name>直接设置镜像

1
2
3

[root@master01 work]# kubectl set image deployment myapp-deployment nginx=nginx:1.18-perl --record
deployment.apps/myapp-deployment image updated

查看rollout history

[root@master01 work]# kubectl rollout history deployment myapp-deployment
deployment.apps/myapp-deployment 
REVISION  CHANGE-CAUSE
1         kubectl create --filename=deployment-defination.yaml --record=true
2         kubectl edit deployment/myapp-deployment --record=true
3         kubectl set image deployment myapp-deployment nginx=nginx:1.18-perl --record=true

当前在REVERSION3的位置

7，使用kubectl rollout undo deployment myapp-deployment 进行回退到上个版本,并查看history

[root@master01 work]# kubectl rollout undo deployment myapp-deployment 
deployment.apps/myapp-deployment rolled back
[root@master01 work]# kubectl rollout history deployment myapp-deployment
deployment.apps/myapp-deployment 
REVISION  CHANGE-CAUSE
1         kubectl create --filename=deployment-defination.yaml --record=true
3         kubectl set image deployment myapp-deployment nginx=nginx:1.18-perl --record=true
4         kubectl edit deployment/myapp-deployment --record=true

结果表明：rollout undo（是把当前REVERSION3要回滚到的上一个位置）REVERSION2变成了最新的REVERSION4。换句话说，不是从3到2，而是2变成了4。

8,修改image为一个不存在的version

使用kubectl rollout status deployment myapp-deployment查看：rollout卡住了

1 2	root@master01 work]# kubectl rollout status deployment myapp-deployment Waiting for deployment "myapp-deployment" rollout to finish: 1 out of 3 new replicas have been updated...

[root@master01 work]# kubectl get pods
NAME                                READY   STATUS             RESTARTS   AGE
myapp-deployment-7c8cf9794b-f5qn7   0/1     ImagePullBackOff   0          80s
myapp-deployment-ddbb47dd8-68l2m    1/1     Running            0          8m13s
myapp-deployment-ddbb47dd8-gv4k9    1/1     Running            0          8m22s
myapp-deployment-ddbb47dd8-rg98d    1/1     Running            0          8m17s

旧pod还在Running并没有被删除，因此application并没有被影响。

rollout update是安全的,rollout必须在新pod充分成功创建后，才会删除旧pod

MyNote

k8s_ReplicaSet&Deployment

ReplicaSet&Deployment

replica

创建replicaset模板文件

example

常用指令

Deployment

创建deployment模板

command

Update&Rollout

Rollout

Deployment策略：

Recreate 和 RollingUpdate (StrategyType)的区别

Rollback (回退)

Summarize Commands

example