At a minimum, the init script needs to install a Java runtime.

Custom prepared images are recommended if the initialization script is taking more than 20 minutes to execute.

Below are examples of initialization scripts, Java is required, others are optional:

1. Ubuntu (Only support SSH)

   # Install Java
   sudo apt-get -y update
   sudo apt-get install -y default-jdk
   
   java -version
   
   # Install Git
   sudo apt-get install -y git
   
   # Install Maven
   MAVEN_VERSION=3.6.3
   
   sudo curl -O https://downloads.apache.org/maven/maven-3/${MAVEN_VERSION}/binaries/apache-maven-${MAVEN_VERSION}-bin.tar.gz
   sudo tar zxvf apache-maven-${MAVEN_VERSION}-bin.tar.gz -C /opt/
   sudo ln -s /opt/apache-maven-${MAVEN_VERSION}/bin/mvn /usr/bin/mvn
   
   mvn --version
   
   # Install Docker
   sudo apt-get install -y apt-transport-https ca-certificates curl software-properties-common
   curl -fsSL https://download.docker.com/linux/ubuntu/gpg | sudo apt-key add -
   sudo add-apt-repository "deb [arch=amd64] https://download.docker.com/linux/ubuntu $(lsb_release -cs) stable"
   sudo apt-get -y update
   sudo apt-get install -y docker-ce
   # Replace ${ADMIN} with admin username.
   sudo gpasswd -a ${ADMIN} docker
   sudo chmod g+rw /var/run/docker.sock
   
   sudo docker --version
           
           

2. Windows via SSH

   You can use this sample.
   Java is required, others are optional.
   We recommend to use SSH rather than inbound agent. You need less init code and get much clearer logs.

3. Windows as an inbound agent

   You can use this sample.
   Java, the agent jar and connecting to Jenkins are required, others are optional.

   Arguments automatically passed to this script are:

   • First argument - Jenkins server URL
   • Second argument - VMName
   • Third argument - shared secret for authenticating to Jenkins.

   The server url should already have a trailing slash. Then execute the following to connect:

   java.exe -jar [slave jar location] [-secret [client secret if required]] [server url]computer/[vm name]/slave-agent.jnlp