Jenkins安装和配置-Linux篇

本文主要介绍在Linux服务器上安装jenkins，采用在Tomcat上部署Jenkins.war包的方式进行安装。服务器上之前已安装JDK等基础环境，此处不再赘述。

安装包下载

Tomcat：本文使用的Tomcat9
Jenkins：点击下载

Tomcat安装

将下载的Tomcat的软件包解压，然后执行bin目录下的startup.sh脚本，启动Tomcat。通过浏览器访问Tomcat，看是否正常启动。

Jenkins安装

将下载的Jenkins的软件包拷贝到Tomcat的webapps目录下，重启Tomcat，访问jenkins。

Jenkins配置

系统配置

1. 全局工具配置
   • 配置maven的setting.xml文件
   • 配置JDK
     
   • 配置Git
     
   • 配置Maven
     
2. 创建任务
   • 新建任务，输入任务名，选择构建一个自由风格的软件项目，确定
     
   • 源码管理，配置代码仓库的地址，选择鉴权信息。
     如果是第一次配置，可点击 添加 - Jenkins 添加鉴权信息
     
   • 构建触发器：根据需要配置触发构建的规则，可以不配置通过手动触发构建。
     
   • 构建环境：配置构建环境信息，可不配置。
   • 构建：选择全局工具配置中配置的maven，填写构建目标。如果构建完成需要执行别的操作可以点击 增加构建步骤选择后续操作。
   • 构建后动作：配置构建完成后的操作
     配置完成后点击保存按钮，任务创建完成。

遇到的问题

1. jenkins无法访问

现象：Tomcat可以正常访问，jenkins无法访问。查看Tomcat的运行日志catalina.out有如下报错：
18-May-2020 15:52:02.008 WARNING [http-nio-8080-exec-1] org.apache.catalina.webresources.Cache.getResource Unable to add the resource at [/scripts/yui/yahoo/yahoo-debug.js] to the cache for web application [/jenkins] because there was insufficient free space available after evicting expired cache entries - consider increasing the maximum size of the cache 18-May-2020 15:52:02.009 WARNING [http-nio-8080-exec-1] org.apache.catalina.webresources.Cache.getResource Unable to add the resource at [/scripts/yui/element/element-debug.js] to the cache for web application [/jenkins] because there was insufficient free space available after evicting expired cache entries - consider increasing the maximum size of the cache 18-May-2020 15:52:02.010 WARNING [http-nio-8080-exec-1] org.apache.catalina.webresources.Cache.getResource Unable to add the resource at [/META-INF/MANIFEST.MF] to the cache for web application [/jenkins] because there was insufficient free space available after evicting expired cache entries - consider increasing the maximum size of the cache

18-May-2020 15:52:06.344 WARNING [Handling GET /jenkins/login from 111.18.96.18 : http-nio-8080-exec-3] org.apache.catalina.webresources.Cache.getResource Unable to add the resource at [/WEB-INF/side-files/hudson/util/HudsonIsLoading/index.html] to the cache for web application [/jenkins] because there was insufficient free space available after evicting expired cache entries - consider increasing the maximum size of the cache 18-May-2020 15:52:06.347 WARNING [Handling GET /jenkins/login from 111.18.96.18 : http-nio-8080-exec-3] org.apache.catalina.webresources.Cache.getResource Unable to add the resource at [/WEB-INF/classes/hudson/util/HudsonIsLoading/login.groovy] to the cache for web application [/jenkins] because there was insufficient free space available after evicting expired cache entries - consider increasing the maximum size of the cache 18-May-2020 15:52:06.348 WARNING [Handling GET /jenkins/login from 111.18.96.18 : http-nio-8080-exec-3] org.apache.catalina.webresources.Cache.getResource Unable to add the resource at [/WEB-INF/classes/hudson/util/HudsonIsLoading/login.default.groovy] to the cache for web application [/jenkins] because there was insufficient free space available after evicting expired cache entries - consider increasing the maximum size of the cache

解决方法：
修改Tomcat的 conf/context.xml ，在之前添加如下代码：

<Resources cachingAllowed="true" cacheMaxSize="102400" />

2.访问jenkins报错有多个jenkins实例

Jenkins detected that you appear to be running more than one instance of Jenkins
解决方法：
使用ps命令查看Tomcat是否启动了两个，如果是杀掉Tomcat进程后重新启动。

3.nohup启动后台进程失败

问题现象：
使用nohup命令启动后台进程，显示命令执行成功，但是后台进程未启动
问题原因：
jenkins在执行完一次构建后会杀死这次build的所有子进程
解决方法：
在脚本中加入如下代码，修改buildId

BUILD_ID=DONTKILLME