Creating a Jenkins Server in a Docker Container

Are you looking for article that shows how to create a Jenkins server in Docker container ? This article might help you on that.
Before reading this article we hope that you have some understating on how docker containerization works. If you are new to docker its better you follow these official Docker documentation before going through this article.

So lets get started .

In this article we will be using the below folder structure. Project folder would be JENKINS

Let me explain what are the files ->

JENKINS/configs/users/admin/config.xml this file contains the jenkins user details. Beacuse in jenkins we need to create a jenkins user who has the access to run scripts , install plugins and run tests.

<?xml version="1.0" encoding="UTF-8"?>
<user>
   <fullName>admin</fullName>
   <properties>
      <jenkins.security.ApiTokenProperty>
         <apiToken>nDByjglevCpwNwQkyx21eOPp86vL4P/m1DFJSae+gJvMMRClpO5raH+wCpKQsBvv</apiToken>
      </jenkins.security.ApiTokenProperty>
      <hudson.model.MyViewsProperty>
         <views>
            <hudson.model.AllView>
               <owner class="hudson.model.MyViewsProperty" reference="../../.." />
               <name>All</name>
               <filterExecutors>false</filterExecutors>
               <filterQueue>false</filterQueue>
               <properties class="hudson.model.View$PropertyList" />
            </hudson.model.AllView>
         </views>
      </hudson.model.MyViewsProperty>
      <hudson.model.PaneStatusProperties>
         <collapsed />
      </hudson.model.PaneStatusProperties>
      <hudson.search.UserSearchProperty>
         <insensitiveSearch>false</insensitiveSearch>
      </hudson.search.UserSearchProperty>
      <hudson.security.HudsonPrivateSecurityRealm_-Details>
         <passwordHash>#jbcrypt:$2a$10$KZr7NUlLVTbMykYeuYLdPOgT/jFSfiLZHI3tqU.BkkzW3chSYi9Ha</passwordHash>
      </hudson.security.HudsonPrivateSecurityRealm_-Details>
      <jenkins.security.LastGrantedAuthoritiesProperty>
         <roles>
            <string>authenticated</string>
         </roles>
         <timestamp>1486734797021</timestamp>
      </jenkins.security.LastGrantedAuthoritiesProperty>
   </properties>
</user>

JENKINS/configs/jenkins_home_config.xml

This config file that supports the Jenkins users permission and security configurations.

<?xml version="1.0" encoding="UTF-8"?> 
<hudson>    
<disabledAdministrativeMonitors />    
<version>1.0</version>    
<numExecutors>2</numExecutors>    
<mode>NORMAL</mode>    
<useSecurity>true</useSecurity>    
<authorizationStrategy class="hudson.security.FullControlOnceLoggedInAuthorizationStrategy">       
<denyAnonymousReadAccess>true</denyAnonymousReadAccess>    </authorizationStrategy>    
<securityRealm class="hudson.security.HudsonPrivateSecurityRealm">       <disableSignup>false</disableSignup>       <enableCaptcha>false</enableCaptcha>    
</securityRealm>    
<disableRememberMe>false</disableRememberMe>    <projectNamingStrategy class="jenkins.model.ProjectNamingStrategy$DefaultProjectNamingStrategy" />    
<workspaceDir>${ITEM_ROOTDIR}/workspace</workspaceDir>    <buildsDir>${ITEM_ROOTDIR}/builds</buildsDir>    
<markupFormatter class="hudson.markup.EscapedMarkupFormatter" />    <jdks />    
<viewsTabBar class="hudson.views.DefaultViewsTabBar" />    <myViewsTabBar class="hudson.views.DefaultMyViewsTabBar" />    <clouds />    
<scmCheckoutRetryCount>0</scmCheckoutRetryCount>    
<views>       
<hudson.model.AllView>          
<owner class="hudson" reference="../../.." />          <name>All</name>          
<filterExecutors>false</filterExecutors>          <filterQueue>false</filterQueue>          
<properties class="hudson.model.View$PropertyList" />       </hudson.model.AllView>    
</views>    
<primaryView>All</primaryView>    <slaveAgentPort>50000</slaveAgentPort>    
<label />    
<nodeProperties />    
<globalNodeProperties /> 
</hudson>

JENKINS/configs/my_super_job_config.xml

These are the jenkins jobs. If you have a existing jenkins server and you want to reuse the same jobs you can follow this link and get a .xml file like below.

<?xml version='1.1' encoding='UTF-8'?>
<project>
<actions/>
<description></description>
<keepDependencies>false</keepDependencies>
<properties/>
<scm class="hudson.plugins.git.GitSCM" plugin="git@4.2.2">
<configVersion>2</configVersion>
<userRemoteConfigs>
<hudson.plugins.git.UserRemoteConfig>
<url>https://sheshanGamage@novigi-business-services-process-improvements.git</url>
<credentialsId>Hi From Sri Lanka</credentialsId>
</hudson.plugins.git.UserRemoteConfig>
</userRemoteConfigs>
<branches>
<hudson.plugins.git.BranchSpec>
<name>*/master</name>
</hudson.plugins.git.BranchSpec>
</branches>
<doGenerateSubmoduleConfigurations>false</doGenerateSubmoduleConfigurations>
<submoduleCfg class="list"/>
<extensions/>
</scm>
<canRoam>true</canRoam>
<disabled>false</disabled>
<blockBuildWhenDownstreamBuilding>false</blockBuildWhenDownstreamBuilding>
<blockBuildWhenUpstreamBuilding>false</blockBuildWhenUpstreamBuilding>
<triggers>
<com.cloudbees.jenkins.plugins.BitBucketTrigger plugin="bitbucket@1.1.11">
<spec></spec>
</com.cloudbees.jenkins.plugins.BitBucketTrigger>
</triggers>
<concurrentBuild>false</concurrentBuild>
<builders>
<hudson.tasks.Shell>
<command>cd /var/jenkins_home/jobs/my_super_job/workspace/EI-MysqlTest
echo &quot;inside the Test Folder&quot;
./deploy.sh -h localhost -p 9443
exit 0
</command>
</hudson.tasks.Shell>
</builders>
<publishers/>
<buildWrappers/>
</project>

JENKINS/configs/my_ultra_job_config.xml
Another jenkins job xml file

<?xml version='1.0' encoding='UTF-8'?>
<project>
<description>
</description>
<keepDependencies>false</keepDependencies>
<properties/>
<scm class="hudson.scm.NullSCM"/>
<canRoam>true</canRoam>
<disabled>false</disabled>
<blockBuildWhenDownstreamBuilding>false</blockBuildWhenDownstreamBuilding>
<blockBuildWhenUpstreamBuilding>false</blockBuildWhenUpstreamBuilding>
<triggers/>
<concurrentBuild>false</concurrentBuild>
<builders/>
<publishers/>
<buildWrappers/>
</project>

JENKINS/docker-compose.yml

Compose is a tool for defining and running multi-container Docker applications. With Compose, you use a YAML file to configure your application’s services. Then, with a single command, you create and start all the services from your configuration.

jenkins2:
container_name: j2
image: j2:v1
environment:
JAVA_OPTS: "-Djava.awt.headless=true"
JAVA_OPTS: "-Djenkins.install.runSetupWizard=false" # Start jenkins unlocked
ports:
- "50000:50000"
- "8080:8080"
volumes:
- /var/jenkins_home

JENKINS/Dockerfile

A Dockerfile is a text document that contains all the commands a user could call on the command line to assemble an image. Using docker build users can create an automated build that executes several command-line instructions in succession.The file we used in this downloads a image from the docker repo and install Maven , Node and install jenkins plugins to run our jenkin jobs.

FROM jenkins/jenkins:alpine
ENV JENKINS_USER admin
ENV JENKINS_PASS admin
# Skip initial setup
ENV JAVA_OPTS -Djenkins.install.runSetupWizard=false
COPY plugins.txt /usr/share/jenkins/plugins.txt
RUN /usr/local/bin/install-plugins.sh < /usr/share/jenkins/plugins.txt
USER root
RUN apk add docker
RUN apk add py-pip
RUN apk add python-dev libffi-dev openssl-dev gcc libc-dev make
RUN pip install docker-compose
COPY /configs/users "$JENKINS_HOME"/users/
# Install Maven
RUN apk add --no-cache curl tar bash
ARG MAVEN_VERSION=3.6.3
ARG USER_HOME_DIR="/root"
RUN mkdir -p /usr/share/maven && \
curl -fsSL http://apache.osuosl.org/maven/maven-3/$MAVEN_VERSION/binaries/apache-maven-$MAVEN_VERSION-bin.tar.gz | tar -xzC /usr/share/maven --strip-components=1 && \
ln -s /usr/share/maven/bin/mvn /usr/bin/mvn
ENV MAVEN_HOME /usr/share/maven
ENV MAVEN_CONFIG "$USER_HOME_DIR/.m2"
# Add the main config file to the jenkins path
COPY /configs/jenkins_home_config.xml "$JENKINS_HOME"/config.xml
# Name the jobs
ARG job_name_1="my_super_job"
ARG job_name_2="my_ultra_job"
# Create the job workspaces
RUN mkdir -p "$JENKINS_HOME"/workspace/${job_name_1}
RUN mkdir -p "$JENKINS_HOME"/workspace/${job_name_2}
# Create the jobs folder recursively
RUN mkdir -p "$JENKINS_HOME"/jobs/${job_name_1}
RUN mkdir -p "$JENKINS_HOME"/jobs/${job_name_2}
# Add the custom configs to the container
COPY /configs/${job_name_1}_config.xml "$JENKINS_HOME"/jobs/${job_name_1}/config.xml
COPY /configs/${job_name_2}_config.xml "$JENKINS_HOME"/jobs/${job_name_2}/config.xml
# Create build file structure
RUN mkdir -p "$JENKINS_HOME"/jobs/${job_name_1}/latest/
RUN mkdir -p "$JENKINS_HOME"/jobs/${job_name_1}/builds/1/
# Create build file structure
RUN mkdir -p "$JENKINS_HOME"/jobs/${job_name_2}/latest/
RUN mkdir -p "$JENKINS_HOME"/jobs/${job_name_2}/builds/1/
RUN apk add --update nodejs nodejs-npm
RUN npm install -g newman
RUN npm install -g newman-reporter-html

JENKINS/plugins.txt

This file contains all the jenkins plugins that needs to run your jenkin jobs. This list contains some of the popular jenkins plugins.

ace-editor
ant
antisamy-markup-formatter
branch-api
cloudbees-folder
credentials
cvs
docker
durable-task
external-monitor-job
git-client
git-server
git
github-api
github-branch-source
github
javadoc
jquery-detached
junit
ldap
mailer
matrix-auth
matrix-project
maven-plugin
metrics
pam-auth
plain-credentials
scm-api
script-security
ssh-credentials
ssh-slaves
subversion
translation
variant
windows-slaves
workflow-aggregator
workflow-api
workflow-basic-steps
workflow-cps-global-lib
workflow-cps
workflow-durable-task-step
workflow-job
workflow-multibranch
workflow-scm-step
workflow-step-api
workflow-support
favorite
token-macro
pipeline-stage-step
blueocean
blueocean-autofavorite
gitlab-plugin

Now we have all the files in our project. So lets run and build the jenkins docker container.Please run all these comands from inside the JENKINS project folder.

Command to create the jenkins image

sudo docker build -t j2:v1 . --no-cache

Command to run the created jenkins image.

sudo docker run --network="host" j2:v1

If you have ran the project several times you would see something like this.

:) Thank You
hope you learnt something from this :)