springboot版本helloworld发布到k8s示例

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操作步骤

  • windows上编写代码
  • 远程linux的docker引擎把代码打成镜像
  • 编写k8s的yaml文件
  • 应用yaml文件,启动服务

前置任务

一. 基于springboot编写hello world代码

1. 代码结构

2. pom文件


<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.1.6.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.kinnylee</groupId>
    <artifactId>k8s-demo</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>k8s-demo</name>
    <description>Demo project for Spring Boot</description>

    <properties>
        <java.version>1.8</java.version>
        <docker.image.prefix>kinnylee</docker.image.prefix>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-redis</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
    </dependencies>

    <!--编译打包成镜像-->
    <build>
        <resources>
            <resource>
                <directory>src/main/docker</directory>
                <filtering>true</filtering>
                <includes>
                    <include>**/Dockerfile</include>
                </includes>
                <targetPath>../docker</targetPath>
            </resource>
        </resources>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
            <plugin>
                <groupId>com.spotify</groupId>
                <artifactId>dockerfile-maven-plugin</artifactId>
                <version>1.4.0</version>
                <configuration>
<!--                    <repository>${docker.image.prefix}/${project.artifactId}</repository>-->
                    <repository>${project.artifactId}</repository>
                    <tag>${project.version}</tag>
                    <buildArgs>
                        <JAR_FILE>target/${project.build.finalName}.jar</JAR_FILE>
                    </buildArgs>
                </configuration>
            </plugin>
        </plugins>
    </build>

</project>

3. Dockerfile文件

FROM openjdk:8-jdk-alpine
ENV  TIME_ZONE  Asia/Shanghai
RUN apk add --no-cache tzdata && \
echo "${TIME_ZONE}" > /etc/timezone && ln -sf /usr/share/zoneinfo/${TIME_ZONE} /etc/localtime

VOLUME /data

ARG JAR_FILE

ADD ${JAR_FILE} app.jar
ENTRYPOINT ["java","-Djava.security.egd=file:/dev/./urandom","-jar","/app.jar"]

4. controller文件

package com.kinnylee.k8sdemo.controller;

import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
public class K8sDemoController {

    @GetMapping("/hello")
    public String hello(){
        return "hello k8s demo.";
    }
}

二. 打包成镜像

如果在liunx下安装idea开发,下面的步骤可省略,直接编译打包即可

liunx下安装IDE比较卡,windows下安装docker兼容性不好。于是采用windows编写代码,远程连接linux中docker放开的TCP端口,进行远程镜像打包

1. 配置远程docker的TCP连接

vim /lib/systemd/system/docker.service
# ExecStart结尾添加:-H tcp://0.0.0.0:2375
[Service]
ExecStart=/usr/bin/dockerd -H fd:// --containerd=/run/containerd/containerd.sock -H tcp://0.0.0.0:2375

2. IDEA中设置Docker执行的远程地址

3. 环境变量中添加DOCKER_HOST

工具名称:Rapid Environment

4. 开始编译打包成镜像

5. 编译成功后的镜像

6. linux上验证正确性

7. 将镜像拷贝到其他节点(有私仓则直接push发布,不需要这一步)

# 保存镜像
docker save k8s-demo:0.0.1-SNAPSHOT -o k8s-demo.tar
# 镜像拷贝到其他机器
scp k8s-demo.tar 10.1.69.100:/data/images
scp k8s-demo.tar 10.1.69.102:/data/images
scp k8s-demo.tar 10.1.69.103:/data/images

# 其他节点上分别执行以下命令,恢复镜像
cd /data/images
docker load < k8s-demo.tar

三. 编写k8s的yaml文件

Deployment

  • deployment.yaml
apiVersion: extensions/v1beta1
kind: Deployment
metadata:
  name: k8s-demo
  namespace: spring-test
spec:
  replicas: 3
  template: 
    metadata: 
      labels: 
        app: k8s-demo
    spec: 
      containers: 
      - name: k8s-demo
        image: kinnylee/k8s-demo:0.0.1-SNAPSHOT
        ports: 
          containerPort: 8080

Service

apiVersion: v1
kind: Service
metadata:
  name: k8s-demo
  namespace: spring-test
spec:
  type: NodePort
  selector:
    app: k8s-demo
  ports:
   - protocol: TCP
     port: 8888
     targetPort: 8080
     nodePort: 30003

四. 开始部署到k8s

1. 创建namespace

# 创建命名空间
kubectl create namespace spring-test
# 验证是否成功
kubectl get ns

2. 创建deployment

# 开始创建deployment
kubectl apply -f deployment.yaml

# 验证是否创建成功
kubectl get deployment -n spring-test

# 验证3个pod是否创建成功
kubectl get pods -n spring-test

# 如果启动不成功,排查原因,pod后面的参数为上一步查询的pod名称
kubectl describe pod k8s-demo-f99976b78-5blxd -n spring-test

3. 创建service

# 创建service
kubectl apply -f service.yaml 

# 验证是否创建成功
kubectl get svc -n spring-test

4. 外部访问服务

  • 如下图:输入k8s节点ip和30003端口号,就可以看到服务可以被访问到了