mirror of https://github.com/easzlab/kubeasz.git
157 lines
4.6 KiB
Markdown
157 lines
4.6 KiB
Markdown
# JAVA WAR 应用迁移 K8S 实践
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初步思路是这样：应用代码与应用配置分离，应用代码打包成 docker 镜像存于内部 harbor 仓库，应用配置使用 configmap 挂载，这样不同的环境只需要修改 configmap 即可部署。
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- 使用 maven 把 java 应用代码打包成 xxx.war
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- 基于 tomcat 镜像和 xxx.war 做成应用 docker 镜像
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- 编写 k8s deployment 文件，在 pod 指定上述应用镜像，同时把应用配置做成 configmap 挂载到 pod 里
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经过多次尝试部署发现问题：configmap配置是可以挂载上去，但是会把目录下其他的文件删掉，而且tomcat 目录 webapps/xxxxx/下其他目录也消失了。原来是因为 tomcat 容器完全启动完成后才会解压 war包，而 configmap 配置文件是一开始就挂载上去了，导致失败。
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- 调整应用镜像打包过程：xxx.war 先解压后再进行应用镜像打包
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## 应用 gitlab CI/CD 集成
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- 在内部gitlab创建项目，上传应用java代码，同时在项目根目录下新加如下目录和文件，配置相应的 gitlab-runner 和 环境变量参数
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``` bash
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├── .app.yaml # k8s deployment 部署模板文件
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├── config.yaml # k8s configmap 配置模板文件
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├── dockerfiles
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│ └── Dockerfile # Dockerfile 文件
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├── .gitlab-ci.yml # gitlab ci 配置文件
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└── .ns.yaml # k8s namespace 和 imagePullSecrets的配置文件
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```
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### gitlab-ci 文件摘要
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``` bash
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variables:
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PROJECT_NS: '$CI_PROJECT_NAMESPACE-$CI_JOB_STAGE'
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APP_NAME: '$CI_PROJECT_NAME-$CI_COMMIT_REF_SLUG'
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stages:
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- package
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- beta
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job_package:
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stage: package
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tags:
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- package-shell
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only:
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- master
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- /^feature-.*$/
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script:
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- mvn clean install -Dmaven.test.skip=true
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- unzip target/xxxx.war -d dockerfiles/project
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- cd dockerfiles && docker build -t harbor.test.lo/project/$CI_PROJECT_NAME:$CI_PIPELINE_ID .
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- docker login -u $HARBOR_USR -p $HARBOR_PWD harbor.test.lo
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- docker push harbor.test.lo/project/$CI_PROJECT_NAME:$CI_PIPELINE_ID
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- docker logout harbor.test.lo
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job_push_beta:
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stage: beta
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tags:
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- beta-shell
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only:
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- master
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- /^feature-.*$/
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when: manual
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script:
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# 替换beta环境的参数配置
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- sed -i "s/PROJECT_NS/$PROJECT_NS/g" config.yaml .app.yaml .ns.yaml
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- sed -i "s/TemplateProject/$APP_NAME/g" config.yaml .app.yaml
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- sed -i "s/DB_HOST/$BETA_DB_HOST/g" config.yaml
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- sed -i "s/DB_PWD/$BETA_DB_PWD/g" config.yaml
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- sed -i "s/APP_REP/$BETA_APP_REP/g" .app.yaml
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- sed -i "s/ProjectImage/$CI_PROJECT_NAME:$CI_PIPELINE_ID/g" .app.yaml
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#
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- mkdir -p /opt/kube/$PROJECT_NS/$APP_NAME
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- cp -f .ns.yaml config.yaml .app.yaml /opt/kube/$PROJECT_NS/$APP_NAME
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- kubectl --kubeconfig=/etc/.beta/config apply -f .ns.yaml
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- kubectl --kubeconfig=/etc/.beta/config apply -f config.yaml
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- kubectl --kubeconfig=/etc/.beta/config apply -f .app.yaml
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# 生产部署与beta环境类同，这里省略
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```
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### Dockerfile 编写
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```
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FROM tomcat:8.5.33-jre8-alpine
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COPY . /usr/local/tomcat/webapps/
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```
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### k8s deployment 配置举例
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```
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---
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apiVersion: extensions/v1beta1
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kind: Deployment
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metadata:
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name: TemplateProject
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namespace: PROJECT_NS
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spec:
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replicas: APP_REP
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template:
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metadata:
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labels:
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run: TemplateProject
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spec:
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containers:
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- name: TemplateProject
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image: harbor.test.lo/project/ProjectImage
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imagePullPolicy: IfNotPresent
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ports:
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- containerPort: 8080
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volumeMounts:
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- name: db-config
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mountPath: "/usr/local/tomcat/webapps/project/xxxx/yyyy/config/datasource.properties"
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subPath: datasource.properties
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imagePullSecrets:
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- name: projectkey1
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volumes:
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- name: db-config
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configMap:
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name: TemplateProject-config
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defaultMode: 0640
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items:
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- path: datasource.properties
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key: datasource.properties
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---
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apiVersion: v1
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kind: Service
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metadata:
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labels:
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run: TemplateProject
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name: TemplateProject
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namespace: PROJECT_NS
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spec:
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ports:
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- port: 80
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protocol: TCP
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targetPort: 8080
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selector:
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run: TemplateProject
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sessionAffinity: None
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```
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### k8s configmap 配置举例
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```
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apiVersion: v1
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kind: ConfigMap
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metadata:
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name: TemplateProject-config
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namespace: PROJECT_NS
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data:
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datasource.properties: |
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dataSource.maxIdle = 5
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dataSource.maxActive = 41
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dataSource.driverClassName = com.mysql.jdbc.Driver
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dataSource.url = jdbc:mysql://DB_HOST:8066/project?useUnicode=true&characterEncoding=utf-8
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dataSource.username = username
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dataSource.password = DB_PWD
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```
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