How to mount Jenkins workspace in docker container

Question

I'm using Jenkins in docker. The /var/jenkins_home is mounted on /var/jenkins-data on my host. My Jenkins can execute docker commands (mount of sockets) and I've installed the git plugin and pipeline plugin.

Now I have a pipeline job named test and the following pipeline:

pipeline {
    agent any
    stages {
        stage('Clone') {
            steps {
                git branch: 'master', url: 'https://github.com/lvthillo/maven-hello-world.git'
            }
        }

        stage('Build in Docker') {
            agent {
                docker {
                    image 'maven:3.5.2'
                    args '-v /var/jenkins_home/workspace/test:/opt/maven -w /opt/maven'
                }
            }

            steps {
                sh 'pwd'
                sh 'mvn -v'
                sh 'mvn clean install'
            }
        }
    }
}

What I want to achieve is cloning my public repo from github. This works. In the next step I want to start a docker container (maven) and print the current directory, the maven version and perform a clean install.

The output of the 3 commands is:

[test@2] Running shell script
+ pwd
/var/jenkins_home/workspace/test@2
[Pipeline] sh
[test@2] Running shell script
+ mvn -v
Apache Maven 3.5.2 (138edd61fd100ec658bfa2d307c43b76940a5d7d; 2017-10-18T07:58:13Z)
Maven home: /usr/share/maven
Java version: 1.8.0_151, vendor: Oracle Corporation
Java home: /usr/lib/jvm/java-8-openjdk-amd64/jre
Default locale: en, platform encoding: UTF-8
OS name: "linux", version: "4.4.86-boot2docker", arch: "amd64", family: "unix"
[Pipeline] sh
[test@2] Running shell script
+ mvn clean install

[INFO] Scanning for projects...
[INFO] ------------------------------------------------------------------------
[INFO] BUILD FAILURE
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 0.179 s
[INFO] Finished at: 2018-01-12T12:12:00Z
[INFO] Final Memory: 5M/31M
[INFO] ------------------------------------------------------------------------
[ERROR] The goal you specified requires a project to execute but there is no POM in this directory (/var/jenkins_home/workspace/test@2). Please verify you invoked Maven from the correct directory. -> [Help 1]

It seems to work because maven is not installed on my host, so it's executed from inside the container, but it's suddenly creating a new workspace (@2) instead of using the existing one from where I cloned the repo. I don't want to clone the repo in my container immediately because I want multiple stages, all with different containers, but all executed on my git repo in my workspace.

What am I doing wrong or how can I fix this? I was thinking it was maybe because of the agent step. my first step can run on any agent (any slave), the docker step will run in the docker container, but must of course run on that same slave als where the git clone was executed.

Answer 1

pipeline {
agent any
stages {
    stage('Clone') {
        steps {
            git branch: 'master', url: 'https://github.com/lvthillo/maven-hello-world.git'
            stash name:'scm', includes:'*'
        }
    }

    stage('Build in Docker') {
        steps {
            unstash 'scm'
            script{
                docker.image('maven:3.5.2').inside{ 
                    sh 'pwd'
                    sh 'mvn -v'
                    sh 'mvn clean install'
                }
            }
        }
    }
}
}

You can use this pipeline even with a multi-node setup. Docker plugin by cloudbees mounts your workspace as a docker workspace too.Hence, it is not necessary to mount any volume unless they are outside the workspace.

Answer 2

My last explanation was helping myself to solve the problem: This text helped me to solve it. I had to ensure that all the steps on my pipeline were using the same agent as the initial one where I performed my git clone:

Addit reuseNode true solved it:

stage('Build in Docker') {
            agent {
                docker {
                    image 'maven:3.5.2'
                    args '-v /var/jenkins_home/workspace/test:/opt/maven -w /opt/maven'
                    reuseNode true
                }
            }

Answer 3

Thanks, the Previous solution works for me. My version for node container and ${PWD} as param

stage('Build Solution') { 
        agent {
            docker {
                image 'node:6-alpine'
                args '-v ${PWD}:/usr/src/app -w /usr/src/app'
                reuseNode true
            }
        }
        steps {
            sh 'npm install'
        }
    }