Exercise 10

You will start a VM using Vagrant as practice environment to set up a distributed build with 2 agents.

Starting up the VMs

To start up the VMs, navigate to this directory. It should contain a Vagrantfile.
Run the command vagrant up. Bringing up the VMs might take some minutes. The two VMs will be available with the IP address 192.168.99.201 and 192.168.99.202. The username/password credentials for those VMs are jenkins:jenkins.

Go to "Manage Jenkins" > "Manage Nodes". You should see a single master node.
Configure the master node by setting the # of executor value to 0. That will take care of never using the master for job workload.
Add new nodes by clicking "New Nodes". Enter an appropriate name and select the option "Permanent Agent". Use the remote directory /home/jenkins/jenkins_slave and set the # of executors to 2. Enter the IP address 192.168.99.201 as host and provide credentials by selecting "Username with password". You will likely have to create a new credential. To keep things easy select "Non verifying Verification Strategy".
Trigger a build. You should see that the build is only executed on the agent and not the master node.
Add one more agent with the IP address 192.168.99.202.
Trigger a build. You should see that the build can be executed on any of the agents.
Configure one of the agents to only build jobs with a specific label e.g. java. Change the "Usage" field to "Only build jobs with label expressions matching this node".
Configure the gradle-initializr job and assign the label java.
Trigger a build of the gradle-initializr job. It is only executed by the dedicated agent.
Trigger other jobs that do not have the label java assigned to them. They are waiting for an agent that can execute the build.

After you are done with the exercise, navigate to the directory containing the Vagrantfile.
Tear down the VM by executing vagrant destroy -f.