springboot版本helloworld发布到k8s示例

操做步骤

• 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

• 安装好k8s集群，可参考另外一篇文章：Centos7安装k8s集群1.15.0版本

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>

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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"] 
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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.";
    }
}

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二. 打包成镜像

若是在liunx下安装idea开发，下面的步骤可省略，直接编译打包便可

liunx下安装IDE比较卡，windows下安装docker兼容性很差。因而采用windows编写代码，远程链接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链接

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

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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. 将镜像拷贝到其余节点（有私仓则直接push发布，不须要这一步）

# 保存镜像
docker save k8s-demo:0.0.1-SNAPSHOT -o k8s-demo.tar
# 镜像拷贝到其余机器
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
 # 其余节点上分别执行如下命令，恢复镜像
cd /data/images
docker load < k8s-demo.tar
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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

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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
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四. 开始部署到k8s

1. 建立namespace

# 建立命名空间
kubectl create namespace spring-test
# 验证是否成功
kubectl get ns
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2. 建立deployment

# 开始建立deployment
kubectl apply -f deployment.yaml
 # 验证是否建立成功
kubectl get deployment -n spring-test
 # 验证3个pod是否建立成功
kubectl get pods -n spring-test
 # 若是启动不成功，排查缘由，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
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3. 建立service

# 建立service
kubectl apply -f service.yaml 
 # 验证是否建立成功
kubectl get svc -n spring-test

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4. 外部访问服务

• 以下图：输入k8s节点ip和30003端口号，就能够看到服务能够被访问到了