在kubernetes集群中部署SpringBoot应用和MySQL

环境准备

需要k8s集群和本地仓库，如果你还没有搭建，建议参考我上面两篇文章 Kubernetes集群搭建详细指南、 为kubernetes创建本地镜像仓库

部署MySQL

首先我们需要创建持久卷和持久卷声明，用来为MySQL挂在存储，不然MySQL重启数据就丢失了。

1）创建持久卷和持久卷声明

将以下的yaml声明保存为mysql-pv.yaml，然后执行apply命令。

apiVersion: v1
kind: Service
metadata:
  name: mysql
  labels:
    app: mysql
spec:
  ports:
    - port: 3306
  selector:
   app: mysql
---
apiVersion: apps/v1
kind: Deployment
metadata:
  name: mysql
spec:
  selector:
    matchLabels:
      app: mysql
  strategy:
    type: Recreate
  template:
    metadata:
      labels:
        app: mysql
    spec:
      containers:
        - image: mysql:5.6
          name: mysql
          env:
            - name: MYSQL_ROOT_PASSWORD
              value: mysql520
          ports:
            - containerPort: 3306
              name: mysql
          volumeMounts:
            - name: mysql-persistent-storage
              mountPath: /var/lib/mysql
      volumes:
        - name: mysql-persistent-storage
          persistentVolumeClaim:
            claimName: mysql-pv-claim

kubectl apply -f mysql-pv.yaml

2）部署MySQL 5.6

这里选择了MySQL5.6的版本，你也可以换成其他的。

将以下的yaml声明保存为mysql-deployment.yaml，然后执行apply命令。

我们创建MySQL的同时创建了Service，Service为集群中的容器通信提供了服务发现功能。

apiVersion: v1
kind: Service
metadata:
  name: mysql
  labels:
    app: mysql
spec:
  ports:
    - port: 3306
  selector:
    app: mysql
---
apiVersion: apps/v1
kind: Deployment
metadata:
  name: mysql
spec:
  selector:
    matchLabels:
      app: mysql
  strategy:
    type: Recreate
  template:
    metadata:
      labels:
        app: mysql
    spec:
      containers:
        - image: mysql:5.6
          name: mysql
          env:
            - name: MYSQL_ROOT_PASSWORD
              value: mysql520
          ports:
            - containerPort: 3306
              name: mysql
          volumeMounts:
            - name: mysql-persistent-storage
              mountPath: /var/lib/mysql
      volumes:
        - name: mysql-persistent-storage
          persistentVolumeClaim:
            claimName: mysql-pv-claim

kubectl apply -f mysql-deployment.yaml

查看部署结果：

[root@k8s-master spring-boot-k8s-app]# kubectl get pods
NAME                     READY   STATUS    RESTARTS   AGE
mysql-7446cc569d-nglnb   1/1     Running   4          40m

部署SpringBoot应用

1）在项目根目录创建Dockerfile

FROM  openjdk:8-jdk
WORKDIR /opt/
COPY target/spring-boot-k8s-app.jar /opt/
EXPOSE 8080
CMD ["java","-Djava.security.egd=file:/dev/./urandom","-Xms400m","-Xmx400m","-jar","/opt/spring-boot-k8s-app.jar", "--spring.profiles.active=prod"]

2）记得修改配置文件中datasource

如下，其中url的第二个mysql即为我们之前创建MySQL的service名称。其他变量通过环境变量的形式读取。

spring:
  datasource:
    url: jdbc:mysql://mysql:3306/demo?useSSL=false&useUnicode=true&characterEncoding=utf-8&serverTimezone=Asia/Shanghai&zeroDateTimeBehavior=convertToNull&autoReconnect=true
    username: ${
     MYSQL_USERNAME}
    password: ${
     MYSQL_PASSWORD}
    initialization-mode: always

3）创建资源定义文件yaml

在项目根目录下创建deploy文件夹，按照如下创建spring-boot-deployment.yaml文件，并放到deploy文件夹下。

kind: Service
apiVersion: v1
metadata:
  name: spring-boot-k8s-app-service
spec:
  type: NodePort
  selector:
    app: spring-boot-k8s-app
  ports:
    - protocol: TCP
      port: 8080
      nodePort: 32082
---
apiVersion: apps/v1
kind: Deployment
metadata:
  name: spring-boot-k8s-app-deployment
spec:
  replicas: 1
  selector:
    matchLabels:
      app: spring-boot-k8s-app
  template:
    metadata:
      labels:
        app: spring-boot-k8s-app
    spec:
      containers:
        - name: spring-boot-k8s-app-controller
          image: 192.168.6.128:5000/spring-boot-k8s-app:20200907-011935
          ports:
            - containerPort: 8080
          env:
            - name: MYSQL_PORT
              value: '3306'
            - name: MYSQL_USERNAME
              value: root
            - name: MYSQL_PASSWORD
              value: mysql520

4）一把梭命令脚本

为了免去手工部署敲命令的烦恼，直接一把梭将命令整合成如下的bash脚本，命名为auto-deploy.sh，并扔进deploy文件夹下。这个脚本就实现了这么几件事：

• maven打包
• 打docker镜像
• 推送镜像到本地仓库
• 更新Deployment资源模板文件的镜像tag
• 按照更新后的文件进行部署

git pull origin master
mvn clean package -DskipTests
tag=$(date +"%Y%m%d-%H%M%S")
if [ $# -eq 1 ]; then
    tag=$1
fi
image=localhost:5000/spring-boot-k8s-app:$tag
imagename=spring-boot-k8s-app:$tag

docker build -t $image .
docker push $image
echo "$image"

echo "$imagename"
pwd

cp deploy/spring-boot-deployment.yaml deploy/spring-boot-deployment-tmp.yaml

sed -i s#spring-boot-k8s-app:[0-9]*-[0-9]*#$imagename# deploy/spring-boot-deployment-tmp.yaml

kubectl apply -f deploy/spring-boot-deployment-tmp.yaml

5）通过脚本完成部署

sh deploy/auto-deploy.sh

查看部署效果，发现调度到node2节点：

[root@k8s-master spring-boot-k8s-app]# kubectl get pods -o wide
NAME                                              READY   STATUS    RESTARTS   AGE     IP            NODE        NOMINATED NODE   READINESS GATES
mysql-7446cc569d-nglnb                            1/1     Running   4          138m    10.244.1.38   k8s-node1   <none>           <none>
spring-boot-k8s-app-deployment-587b6dc8c8-bx792   1/1     Running   0          5m48s   10.244.2.29   k8s-node2   <none>           <none>

查看node2的ip：

[root@k8s-master spring-boot-k8s-app]# kubectl get nodes -o wide
NAME         STATUS   ROLES    AGE   VERSION   INTERNAL-IP     EXTERNAL-IP   OS-IMAGE                KERNEL-VERSION               CONTAINER-RUNTIME
k8s-master   Ready    master   2d    v1.19.0   192.168.6.128   <none>        CentOS Linux 7 (Core)   3.10.0-957.12.2.el7.x86_64   docker://18.6.1
k8s-node1    Ready    <none>   2d    v1.19.0   192.168.6.131   <none>        CentOS Linux 7 (Core)   3.10.0-957.12.2.el7.x86_64   docker://18.6.1
k8s-node2    Ready    <none>   2d    v1.19.0   192.168.6.132   <none>        CentOS Linux 7 (Core)   3.10.0-957.12.2.el7.x86_64   docker://18.6.1

由于当前springboot项目对应的Service为NodePort类型，那么它可以从集群外部通过NodeIp和NodePort进行访问。直接通过宿主机浏览器访问http://192.168.6.132:32082/ 地址即可看到效果。

项目源码已上传到GitHub spring-boot-k8s-app，有兴趣可以了解下。