1. Install JDK

2. Install Jenkins, you can add restart after your jenkins url to restart jenkins.

   It consist of following default folder:

   /usr/lib/jenkins
   /var/lib/jenkins
   /etc/sysconfig/jenkins
   /var/log/jenkins/jenkins.log
   

3. Install Maven and SVN

4. Install Tomcat, make sure tomcat has host-manager and manager app, otherwise war cannot be deployed.

   Also edit tomcat-users.xml, add <user username="deployer" password="deployer" roles="manager-script" />, this user name/password is used to connect to tomcat for Jenkins, this user role should contain manager-script.

5. Create a Jenkins project, enter a project name then choose Freestyle project, if project name is HelloWorld, then Jenkins will create a HelloWorld folder under /var/lib/jenkins/workspace/

   

6. In General tab, you can check Discard old builds, strategy is Log rotation, then input max # of builds to keep, this is optional.

   

7. Config Source Code Management, you can check Git or Subversion.

   For Subversion, input Repository URL and Credentials which is user name and password to check out source code from svn. Then choose the repository depth.

   If Repository URL is http://192.168.2.102:8090/svn/test/JenkinTest, then Jenkins will create a folder named JenkinTest under /var/lib/jenkins/workspace/<your project name>/. If it detects svn has changes, then it will check out source code from svn to this folder and build it.

   

8. Config Build Triggers, that is when to trigger the build automatically.

   If you check Poll SCM and Schedule is H/5 * * * *, it means Jenkins will check svn every 5 minutes, if code has change, then it will run the build process.

   

9. Add Build Step, if you use Maven to build, you can select Invoke top-level Maven targets, then input maven goals to build.

   

10. Add post build action to deploy war to tomcat after install Deploy to container plugin.

    deploy war/ear to a container should be selected.

    value of war/ear files should be <your svn project folder name>/target/*.war or */target/*.war if this value is wrong, then Jenkins cannot run this depoly action, there is no error message in console output and /var/log/jenkins/jenkins.log.

    In this section, Context Path is your web app name in tomcat, you can leave it empty.

    Then select container and input the user name/password to connect it.

    Input Tomcat URL, like http://192.168.2.102:8181/

    

Problems

Jenkins installation successfully base on above steps in my pc. However it failed in another linux pc.

Jenkins is 2.108 in my pc, 2.107.1 in failed pc. I have no idea that why they are different because I installed it base on same instruction of jenkins doc.

both they are centos 7 and have same jdk version 1.8.

Maven is installed local in them.

Cannot run program “mvn” (in directory …):error=2, No such file or directory

Specify maven installation in Jenkins: Jenkins -> Global Tool Configuration -> Maven, input maven name and maven home, uncheck Install automatically. Then in Build section of project config, select maven version instead default.

JAVA_HOME is not defined correctly

Go to Manage Jenkins -> Configure System -> Global Properties -> Check Environment variables -> input JAVA_HOME and JAVA_HOME PATH.

Cannot delete *.pom in jenkins workspace

or change permission manually.

Failed to undeploy

The Tomcat Manager responded “FAIL - Context [/Test] is defined in server.xml and may not be undeployed.

As the error message implies, there is context Test defined in server.xml which cause this problem.

Go to tomcat -> conf -> server.xml, find out like:

  <Host name="localhost"  appBase="/var/www/webapps" unpackWARs="true" autoDeploy="true">
      <Context docBase="/var/www/webapps/Test" path="/Test" reloadable="false" />  

delete context definition.

Note: If you change webapp directory, like above, then the manager and host-manager should be moved, in this case, they should be in /var/www/webapps/