KubernetesNotes7:Deployment部署应用

1. 简介

控制Pod，使用Pod拥有多副本，自愈，扩缩容等能力。

2. 自愈能力

# 比较方式一：创建
kubectl run mynginx --image=nginx
# 方式二：deployment创建，自愈能力
kubectl create deployment mytomcat --image=tomcat:8.5.68

# 方式一创建的删除了就永久删除了，deployment删除（模拟宕机），会生成新的一个,自愈能力！
kubectl delete pod mynginx 
kubectl delete pod mytomcat-6f5f895f4f-stm2q

root@docker01:/home# kubectl get deploy
NAME       READY   UP-TO-DATE   AVAILABLE   AGE
mytomcat   1/1     1            1           8m27s
root@docker01:/home# kubectl delete deploy mytomcat
deployment.apps "mytomcat" deleted
root@docker01:/home#

3. 多副本能力

3.1 命令创建

# 部署3个副本
kubectl create deployment my-dep --image=nginx --replicas=3

3.2 可视化界面创建

• 应用部署在多个机器（鸡蛋不放在一个篮子里🤣）

root@docker01:/home# kubectl get pod -owide
NAME                        READY   STATUS    RESTARTS   AGE     IP                NODE       NOMINATED NODE   READINESS GATES
my-dep-01-686cfb7bf-4g6xz   1/1     Running   0          2m58s   192.168.244.68    docker04   <none>           <none>
my-dep-01-686cfb7bf-84tmf   1/1     Running   0          2m58s   192.168.243.139   docker03   <none>           <none>
my-dep-01-686cfb7bf-dgx8k   1/1     Running   0          2m58s   192.168.244.69    docker04   <none>           <none>
my-dep-01-686cfb7bf-rq8mb   1/1     Running   0          2m58s   192.168.244.67    docker04   <none>           <none>
my-dep-01-686cfb7bf-t8xwt   1/1     Running   0          2m58s   192.168.180.2     docker02   <none>           <none>
my-dep-5b7868d854-5vq9f     1/1     Running   0          5m15s   192.168.243.138   docker03   <none>           <none>
my-dep-5b7868d854-dl9xm     1/1     Running   0          5m15s   192.168.244.66    docker04   <none>           <none>
my-dep-5b7868d854-mdf6r     1/1     Running   0          5m15s   192.168.243.137   docker03   <none>           <none>
root@docker01:/home#

3.3 配置文件创建

apiVersion: apps/v1
kind: Deployment
metadata:
  name: my-dep
  labels:
    app: my-dep
#  namespace: default
spec:
  replicas: 3
  selector:
    matchLabels:
      app: my-dep
  template:
    metadata:
      labels:
        app: my-dep
    spec:
      containers:
      - image: nginx
        name: nginx

4. 扩缩容

4.1 准备

4.2 扩容成5个副本

# 扩容
kubectl scale deploy/my-dep --replicas=5
# 缩容
kubectl scale deploy/my-dep --replicas=2

# 相当于执行以下命令，修改参数
kubectl edit deploy my-dep

5. 自愈&故障转移

• 当Pod出现问题，deployment保证副本数量

# 监控
watch -n 1 kubectl get pod 
# 监控，-w是K8S中打印出状态变化过程
kubectl get pod -w

6. 滚动更新

# 查看之前Pod使用的镜像
kubectl get deploy my-dep -oyaml

# 更新镜像，--record记录下更新
kubectl set image deploy/my-dep nginx=nginx:1.16.1 --record

# 执行上述命令，监控显示如图
kubectl get pod -w

# 相当于执行以下命令，修改参数
kubectl edit deploy my-dep

7. 版本回退

# 查看历史记录
kubectl rollout history deploy/my-dep
# 回滚
kubectl rollout undo deploy/my-dep --to-revision=1

# 监控
root@docker01:/home# kubectl get pod -w

# 查看镜像
kubectl get deploy/my-dep -oyaml|grep image

• 最后一次部署时nginx:1.16.1 ，已经回退为nignx

总结