目录

• kubernetes/k8s中deployments yaml 示例
• • deployments的创建
  • deployments的更新
  • deployments image的升级
  • deployments的回滚
  • deployment的删除

kubernetes/k8s中deployments yaml 示例

本文介绍kubernetes/k8s中deployments的生命周期管理,包含创建，更新，升级，回退，删除。 并给出示例

deployments的创建

下面我们将创建一个hello-server的deployment

创建文件deployment.yaml，内容如下

apiVersion: apps/v1
kind: Deployment
metadata:
  name: deploy-hello-server
spec:
  selector:
    matchLabels:
      app: deploy-hello-server
  template:
    metadata:
      labels:
        app: deploy-hello-server
    spec:
      containers:
      - image: wssiqi/hello-server:v1
        name: hello-server

应用deployment并查看状态

$ kubectl apply -f deployment.yaml
deployment.apps/deploy-hello-server created
$ kubectl get pods
NAME                                   READY   STATUS    RESTARTS   AGE
deploy-hello-server-79846bbbd6-z8p77   1/1     Running   0          4s

deployments的更新

下面我们尝试将deployment中replica的数量设置为2

更新deployment.yaml内容如下，添加replicas: 2

apiVersion: apps/v1
kind: Deployment
metadata:
  name: deploy-hello-server
spec:
  selector:
    matchLabels:
      app: deploy-hello-server
  replicas: 2
  template:
    metadata:
      labels:
        app: deploy-hello-server
    spec:
      containers:
      - image: wssiqi/hello-server:v1
        name: hello-server

更新deployment

$ kubectl apply -f deployment.yaml
deployment.apps/deploy-hello-server configured
$ kubectl get pods
NAME                                   READY   STATUS    RESTARTS   AGE
deploy-hello-server-79846bbbd6-qnwtn   1/1     Running   0          15s
deploy-hello-server-79846bbbd6-z8p77   1/1     Running   0          8m10s

可以看到pod的数量已经更新到设置的值replicas: 2

deployments image的升级

演示如何进行rolling upgrade

首先确保hello-server的deployment已经创建，参考上面的文档

通过kubectl set image来进行升级

先检查deployment里面的image情况

$ kubectl get deployments
NAME                  READY   UP-TO-DATE   AVAILABLE   AGE
deploy-hello-server   2/2     2            2           17m
$ kubectl describe deployments deploy-hello-server
Name:                   deploy-hello-server
Namespace:              default
CreationTimestamp:      Thu, 03 Jun 2021 03:19:59 -0400
Labels:                 <none>
Annotations:            deployment.kubernetes.io/revision: 1
Selector:               app=deploy-hello-server
Replicas:               2 desired | 2 updated | 2 total | 2 available | 0 unavailable
StrategyType:           RollingUpdate
MinReadySeconds:        0
RollingUpdateStrategy:  25% max unavailable, 25% max surge
Pod Template:
  Labels:  app=deploy-hello-server
  Containers:
   hello-server:
    Image:        wssiqi/hello-server:v1
    Port:         <none>
    Host Port:    <none>
    Environment:  <none>
    Mounts:       <none>
  Volumes:        <none>
Conditions:
  Type           Status  Reason
  ----           ------  ------
  Progressing    True    NewReplicaSetAvailable
  Available      True    MinimumReplicasAvailable
OldReplicaSets:  <none>
NewReplicaSet:   deploy-hello-server-79846bbbd6 (2/2 replicas created)
Events:
  Type    Reason             Age    From                   Message
  ----    ------             ----   ----                   -------
  Normal  ScalingReplicaSet  17m    deployment-controller  Scaled up replica set deploy-hello-server-79846bbbd6 to 1
  Normal  ScalingReplicaSet  9m32s  deployment-controller  Scaled up replica set deploy-hello-server-79846bbbd6 to 2

可以看到这个deployment的image只有wssiqi/hello-server:v1
我们将这个image升级为 wssiqi/hello-server:v2

$ kubectl set image deployments/deploy-hello-server hello-server=wssiqi/hello-server:v2
deployment.apps/deploy-hello-server image updated

命令中的参数介绍如下
deployments/deploy-hello-server: deployments/为固定写法, deploy-hello-server 来自于 Name: deploy-hello-server
hello-server=wssiqi/hello-server:v2: hello-server是container名字，来自于hello-server:, wssiqi/hello-server:v2 表示将containerhello-server的image设置为v2版本

检查是否已经更新完成

$ kubectl describe deployments deploy-hello-server | grep Image
    Image:        wssiqi/hello-server:v2
$ kubectl get pods
NAME                                   READY   STATUS    RESTARTS   AGE
deploy-hello-server-557fb9bcb7-857kq   1/1     Running   0          3m48s
deploy-hello-server-557fb9bcb7-f7tch   1/1     Running   0          2m41s

通过上面命令发现deployment已经更新完成，并且新的pod已经启动 (NAME和之前的不同)

通过deployment.yaml文件来更新image

通过deployment.yaml来将image更新为v3版本

更新deployment.yaml文件内容如下

apiVersion: apps/v1
kind: Deployment
metadata:
  name: deploy-hello-server
spec:
  selector:
    matchLabels:
      app: deploy-hello-server
  replicas: 2
  template:
    metadata:
      labels:
        app: deploy-hello-server
    spec:
      containers:
      - image: wssiqi/hello-server:v3
        name: hello-server

应用新的deployment

$ kubectl apply -f deployment.yaml
deployment.apps/deploy-hello-server configured
$ kubectl get deployments -o wide
NAME                  READY   UP-TO-DATE   AVAILABLE   AGE   CONTAINERS     IMAGES                   SELECTOR
deploy-hello-server   2/2     2            2           36m   hello-server   wssiqi/hello-server:v3   app=deploy-hello-server

可以看到deployments的IMAGE已经更新为v3版本

deployments的回滚

当我们发现新的image有问题，可以通过kubectl来进行回滚

首先查看更新的history

$ kubectl rollout history deployment deploy-hello-server
deployment.apps/deploy-hello-server
REVISION  CHANGE-CAUSE
1         <none>
2         <none>
3         <none>

表示总共有三次更新(第一次为创建)

查看各个版本的内容

$ kubectl rollout history deployment deploy-hello-server --revision=1
deployment.apps/deploy-hello-server with revision #1
Pod Template:
  Labels:       app=deploy-hello-server
        pod-template-hash=79846bbbd6
  Containers:
   hello-server:
    Image:      wssiqi/hello-server:v1
    Port:       <none>
    Host Port:  <none>
    Environment:        <none>
    Mounts:     <none>
  Volumes:      <none>

上面的版本查看了revision=1的内容

回滚到revision=1

$ kubectl rollout undo deployment deploy-hello-server --to-revision=1
deployment.apps/deploy-hello-server rolled back

查看当前状态

$ kubectl get deployments -o wide
NAME                  READY   UP-TO-DATE   AVAILABLE   AGE   CONTAINERS     IMAGES                   SELECTOR
deploy-hello-server   2/2     2            2           50m   hello-server   wssiqi/hello-server:v1   app=deploy-hello-server

可以看到已经回滚到v1版本，并且READY和AVAILABLE都正常

deployment的删除

介绍如何删除deployment

查看deployment

$ kubectl get deployments -o wide
NAME                  READY   UP-TO-DATE   AVAILABLE   AGE   CONTAINERS     IMAGES                   SELECTOR
deploy-hello-server   2/2     2            2           53m   hello-server   wssiqi/hello-server:v1   app=deploy-hello-server

删除deployment

$ kubectl delete deployments deploy-hello-server
deployment.apps "deploy-hello-server" deleted

deployment和pod都已经没了

$ kubectl get deployments
No resources found in default namespace.
[[email protected] deployment-example]$ kubectl get pods
No resources found in default namespace.

参考文档:
https://kubernetes.io/docs/concepts/workloads/controllers/deployment/