Usually, Jenkins controller and Jenkins agent are located in the same network, therefore it is quite easy to adopt Jenkins agents using SSH. This time we will talk about the situation when Jenkins controller and bunch of other DevOps tools are running in "network A" and Jenkins agents are running in "network B". Quite often connections from A to B are rejected, however, connections from B to A are accepted. There might be various reasons, in general, network B has elevated security expectations. The typical setup is Jenkins controller located in public cloud and Jenkins agent(s) located in a private customer network. Private customer network might be needed in such because some sort of higher data privacy requirements must be matched or some specialised hardware is present in customer premises and it cannot be accessible directly from the public internet.


The recommended solution is controller/agent setup, when the controller runs in a public environment and agent is running on a server located in a private network. The agent is also called "on-premise executor" (OPE). Jobs are then performing jobs/tasks on such agent in internal/private networks. Jenkins Agent has an active connection from the internal network to internet accessible Jenkins Master via recommended JNLP port tcp/9000 and keeps listening to builds/jobs. Port can be changed, but we will keep talking about 9000. NO direct or NAT network connection is required from the internet to internal network. It is a secure and simple solution.

  • Network
    • firewall opening for port tcp/9000 from relevant source agent(s) IP(s) in internal network towards internet in general (destination
      • network layer (using TDS portal network functionality)
      • operating system layer (firewalld if needed)
  • Jenkins controller running in public
    • Decide which port you are going to use as we use fixed setup in our case. We are choosing 9000 in this guide.
    • Make sure to have port 9000 opened:
      • on network/firewall layer - Firewall
      • in OS level, for example firewalld:

        firewall-cmd --add-port=9000/tcp --permanent
        firewall-cmd --reload
    • Listening on JNLP port tcp/9000
    • node added according to the following steps
      • Go to (remember to use correct URL of your Jenkins controller)
      • Set "Node name" to relevant name useful for you
      • Choose "Permanent"
      • Set "Remote root directory" to "/home/jenkins-agent"
      • Set "Launch method" to "Launch agent by connecting it to the controller" previously called "Launch agent via Java Web Start"
      • Click "Save"
    • now go to newly created node and copy secret/token for connecting agent
      • Go to (remember to use correct URL of your Jenkins controller and replace XXX with the name of your node)
      • You will see something like:

        Run from agent command line:
        java -jar agent.jar -jnlpUrl -secret 8b2911d98400bad5d45635b812b5f2e8e7c1d216bbbae9422a3ba57c691bf762 -workDir "/home/jenkins-agent"
        Run from agent command line, with the secret stored in a file:
        echo 8b2911d98400bad5d45635b812b5f2e8e7c1d216bbbae9422a3ba57c691bf762 > secret-file
        java -jar agent.jar -jnlpUrl -secret @secret-file -workDir "/home/jenkins-agent"

        Please copy only the secret, which is for example in this case "8b2911d98400bad5d45635b812b5f2e8e7c1d216bbbae9422a3ba57c691bf762"

  • running in public
  • Jenkins agent node (slave) - or so-called "on-premise executor"
    • running on a server in the internal network(s)
    • agent service(s) with service auto-start to assure automatic re-connect to Jenkins controller at any time even after server reboot
      • Install dependencies
        • CentOS

          yum install java-11-openjdk-devel git -y
          # you can install also other dependencies that will be required for your jobs
        • Ubuntu

          apt-get update; apt-get install openjdk-11-jdk git -y
          # you can install also other dependencies that will be required for your jobs
      • Installing agent
        • Prepare a folder for config

          mkdir -p /data/configs
          mkdir -p /opt/jenkins-agent
        • Create service file /opt/jenkins-agent/jenkins-agent.service

          Description=Jenkins Agent - On Premise Executor

          # EnvironmentFile cannnot be used on Debian/Ubuntu anymore - Reference:
          # So we are using drop-in config /etc/systemd/system/jenkins-agent.service.d/local.conf
          ExecStart=/usr/bin/java -Xms${JAVA_MEMORY} -Xmx${JAVA_MEMORY} -jar /opt/jenkins-agent/agent.jar -jnlpUrl ${CONTROLLER_URL}/computer/${NODE_NAME}/jenkins-agent.jnlp -secret ${SECRET} -workDir "${WORK_DIR}"

        • Create config file /data/configs/jenkins-agent.conf

        • Create script /opt/jenkins-agent/jenkins-agent-install

          if [ -f $OLD_CONF ];then mv -f $OLD_CONF $MAINCONFIG;fi
          source $MAINCONFIG
          if [ -d $OLD_HOME ];then
            sed -i 's#^WORK_DIR.*#WORK_DIR=/home/jenkins-agent#g' $MAINCONFIG
            source $MAINCONFIG
            # Stopping old service
            systemctl stop jenkinsope
            sleep 10
            mv $OLD_HOME $WORK_DIR
            userdel -rf $OLD_USER
            rm -rf /etc/systemd/system/jenkins-agent.service.d
            rm -f /usr/lib/systemd/system/jenkinsope.service
          useradd -m -s /bin/bash $SERVICE_USER 2> /dev/null
          mkdir -p $WORK_DIR/.ssh
          chmod 700 $WORK_DIR/.ssh
          touch $WORK_DIR/.ssh/config
          chmod 600 $WORK_DIR/.ssh/*
          echo "Changing ownership of home/work folder ($WORK_DIR) and its content (can take long time with many files)..."
          curl -s ${CONTROLLER_URL}/jnlpJars/agent.jar -o $AGENT_APP_HOME/agent.jar
          chmod 644 $AGENT_APP_HOME/agent.jar
          install -D -m 644 $AGENT_APP_HOME/jenkins-agent.service /usr/lib/systemd/system/jenkins-agent.service
          mkdir -p /etc/systemd/system/jenkins-agent.service.d
          echo "[Service]" > /etc/systemd/system/jenkins-agent.service.d/local.conf
          sed 's#^#Environment=#g' $MAINCONFIG >> /etc/systemd/system/jenkins-agent.service.d/local.conf
          systemctl daemon-reload
          systemctl restart jenkins-agent
          systemctl enable jenkins-agent
          systemctl status jenkins-agent
          echo "0 4 * * * root $AGENT_APP_HOME/jenkins-agent-install" > /etc/cron.d/jenkins-agent-update
        • Run install script

          chmod +x /opt/jenkins-agent/jenkins-agent-install
      • Uninstalling agent (for cleanup purposes or if you messed up something)
        • Create script /opt/jenkins-agent/jenkins-agent-uninstall

          systemctl disable jenkins-agent
          systemctl stop jenkins-agent
          rm -f /usr/lib/systemd/system/jenkins-agent.service
          rm -rf /etc/systemd/system/jenkins-agent.service.d
          systemctl daemon-reload
          userdel -r jenkins-agent
          rm -rf /home/jenkins-agent
        • Run install script

          chmod +x /opt/jenkins-agent/jenkins-agent-uninstall

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