Kubenetes：如何发布Java程序

素颜马尾好姑娘i 2022-12-01 05:15 84阅读 0赞

**目录**

一、准备Java应用

二、创建docker镜像

三、上传docker镜像

四、创建minikube容器

--------------------

如何将Java程序发布到Kubenetes，本文通过一个简单的例子来说明。

开发环境:

> Windows 10 Home  
> Docker Toolbox  
> virtualbox  
> minikube

### 一、准备Java应用 ###

创建Maven工程，Java代码：

package com.test.server;
    
    import org.springframework.boot.SpringApplication;
    import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
    import org.springframework.boot.autoconfigure.SpringBootApplication;
    import org.springframework.boot.autoconfigure.jdbc.DataSourceAutoConfiguration;
    import org.springframework.boot.autoconfigure.web.servlet.error.ErrorMvcAutoConfiguration;
    import org.springframework.context.ConfigurableApplicationContext;
    
    @SpringBootApplication
    @EnableAutoConfiguration(exclude = { DataSourceAutoConfiguration.class, ErrorMvcAutoConfiguration.class })
    public class App {
    
    	public static void main(String[] args) {
    		ConfigurableApplicationContext ctx = SpringApplication.run(App.class, args);
    		ctx.registerShutdownHook();
    	}
    }

package com.test.server;
    
    import org.springframework.web.bind.annotation.GetMapping;
    import org.springframework.web.bind.annotation.RequestMapping;
    import org.springframework.web.bind.annotation.RestController;
    
    @RequestMapping("/")
    @RestController
    public class BaseController {
    
    	@GetMapping(path = { "index" })
    	public String doIndex() {
    		return "login";
    	}
    
    	@GetMapping("welcome.do")
    	public String doHeartbeat() {
    		return "welcome";
    	}
    }

application.properties

> spring.application.name=kube-hello  
> server.port=7001

pom.xml

<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>
    
    	<groupId>com.test</groupId>
    	<artifactId>kube-hello</artifactId>
    	<version>0.0.1-SNAPSHOT</version>
    	<packaging>jar</packaging>
    
    	<name>kube-hello</name>
    	<url>http://maven.apache.org</url>
    
    	<properties>
    		<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    	</properties>
    
    	<parent>
    		<groupId>org.springframework.boot</groupId>
    		<artifactId>spring-boot-starter-parent</artifactId>
    		<version>2.3.3.RELEASE</version>
    		<relativePath />
    	</parent>
    
    	<dependencies>
    		<dependency>
    			<groupId>org.springframework.boot</groupId>
    			<artifactId>spring-boot-starter-web</artifactId>
    		</dependency>
    		<dependency>
    			<groupId>junit</groupId>
    			<artifactId>junit</artifactId>
    			<scope>test</scope>
    		</dependency>
    	</dependencies>
    
    	<build>
    		<pluginManagement>
    			<plugins>
    				<plugin>
    					<groupId>org.springframework.boot</groupId>
    					<artifactId>spring-boot-maven-plugin</artifactId>
    					<version>2.3.3.RELEASE</version>
    					<configuration>
    						<mainClass>com.test.server.App</mainClass>
    						<layout>JAR</layout>
    					</configuration>
    					<executions>
    						<execution>
    							<goals>
    								<goal>repackage</goal>
    							</goals>
    						</execution>
    					</executions>
    				</plugin>
    			</plugins>
    		</pluginManagement>
    	</build>
    </project>

将当前目录切换到工程目录kube-hello，若使用spring-boot生成jar

> mvn clean package spring-boot:repackage -f pom.xml  -Dmaven.test.skip=true

### 二、创建docker镜像 ###

在kube-hello目录下创建Dockerfile

# 基于Java8镜像
    FROM java:8
    
    # 在容器中创建目录，将本地文件夹挂在到容器目录
    VOLUME /app
    
    # 更改容器中的工作目录
    WORKDIR /app
    
    # 复制文件到容器
    ADD ./target/kube-hello-0.0.1-SNAPSHOT.jar /app/kube-hello.jar
    
    # 声明需要暴露的端口
    EXPOSE 7080
    
    # 配置容器启动后执行的命令
    ENTRYPOINT ["java","-jar","/app/kube-hello.jar"]

启动Docker Quickstart Terminal后，执行如下命令：

创建images

> $ docker build -t kube-hello:0.0.1 .

创建完成后可查询到创建的image

> $ docker images
> 
> REPOSITORY            TAG                 IMAGE ID            CREATED             SIZE  
> kube-hello            0.0.1               f8f4169625c1        18 minutes ago      660MB

可将docker运行起来，来查看image是不断正确创建

运行image，并开放7080供外部访问：

> docker run --name kube-hello-service -d -p 7080:7001 kube-hello:0.0.1

可通过如下命令查看到容器运行状态：

> docker container ls -a

如何状态不正常，可通过如下命令查看应用日志：

> docker logs <container id>

一旦容器正常运行，可进入到container实例中：

> docker exec -it <container id>  sh

另外，需要在VirtulBox中找到Default实例，在其中的“端口转发”中设置对7080开放，这样在本机就可以通过如下URL访问应用了：

> http://127.0.0.1:7080/index

### 三、上传docker镜像 ###

为了让minikube能创建容器，需要上传docker镜像，上传时需要先登录

> $ docker login

如果出现以下问题：

> Login with your Docker ID to push and pull images from Docker Hub. If you don't have a Docker ID, head over to https://hub.docker.com to create one.  
> Username (XXXXX): XXXXX  
> Password:  
> Error response from daemon: Get https://registry-1.docker.io/v2/: dial tcp: lookup registry-1.docker.io on 10.0.2.3:53: server misbehaving

修改方法：

登录到docker所在的default虚拟机

> sudo vi /etc/resolv.conf

将nameserver 修改为

> nameserver 8.8.8.8

给docker镜像打标记：

> $ docker tag f8f4169625c1 XXXXX/kube-hello:v1

将docker镜像上传：

> $ docker push XXXXX/kube-hello:v1

### 四、创建minikube容器 ###

deployment.yaml

apiVersion: apps/v1
    kind: Deployment
    metadata:
      name: kube-hello-deployment
    spec:
      selector:
        matchLabels:
          app: kube-hello-app
      replicas: 2
      minReadySeconds: 15
      strategy:
        type: RollingUpdate
        rollingUpdate: 
          maxUnavailable: 1
          maxSurge: 1
      template:
        metadata:
          labels:
            app: kube-hello-app
        spec:
          containers:
            - image: XXXXX/kube-hello:v1
              imagePullPolicy: Always
              name: kube-hello
              ports:
                - containerPort: 7001
    ---
    apiVersion: v1
    kind: Service
    metadata:
      name: kube-hello-service
    spec:
      ports:
      - port: 8001
        targetPort: 7001
      selector:
        app: kube-hello-app

启动minikube

> $ minkube start

创建容器在：

> kubectl apply -f deployment.yaml

可通过如下命令查看创建的资源：

> kubectl get pods --show-labels -o wide  
> kubectl get deployment --show-labels -o wide  
> kubectl get services --show-labels -o wide

比如：

> $ kubectl get services --show-labels -o wide  
> NAME                 TYPE        CLUSTER-IP     EXTERNAL-IP   PORT(S)    AGE   SELECTOR             LABELS  
> kube-hello-service   ClusterIP   10.107.157.3   <none>        8001/TCP   2m    app=kube-hello-app   <none>

使用minikube ssh登录后，执行如下命令就可以查看到结果

> curl http://10.107.157.3:8001/index

如果创建的资源不再使用，可能如下命令删除：

> kubectl delete pods --all  
> kubectl delete deployments --all  
> kubectl delete service --all

参考文档  
[Error response from daemon: Get https://registry-1.docker.io/v2/: dial tcp: lookup registry-1.docker.io on 192.168.65.1:53: no such host][Error response from daemon_ Get https_registry-1.docker.io_v2_ dial tcp_ lookup registry-1.docker.io on 192.168.65.1_53_ no such host]  
[Docker网络原则入门][Docker]

[Error response from daemon_ Get https_registry-1.docker.io_v2_ dial tcp_ lookup registry-1.docker.io on 192.168.65.1_53_ no such host]: https://stackoverflow.com/questions/47580528/error-response-from-daemon-get-https-registry-1-docker-io-v2-dial-tcp-look
[Docker]: http://dockone.io/article/455