100 Days of DevOps — Day 61-Jenkins Agent Node

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Welcome to Day 61 of 100 Days of DevOps, Focus for today is Jenkins Agent Node

Yesterday I showed you how to set up Jenkins Server

100 Days of DevOps — Day 60-Introduction to Jenkins

The above setup works great in a small environment but as your team grows you need to scale up your Jenkins and in those situations, you need Master/Agent setup. In Master/Agent setup, Master acts as a control node and Jenkins with the agent installed to take care of the execution of all the jobs.

Requirement

• Jenkins Master
• Agent Node

NOTE: I am performing all the steps on Centos7

Step1: Install the necessary package on the agent node

yum -y install java-1.8.0-openjdk git

• In this case, I am installing java and git
• You don’t Jenkins rpm package on the agent machine

Step2: Create user and copy the ssh key from Master to agent node

# useradd jenkins
visudo
jenkins ALL=(ALL)       NOPASSWD: ALL
# mkdir jenkins_build

• Then copy the key generated on Day60 from master to agent node

$ ssh-copy-id jenkins@172.31.29.138
# To test the connectivity
$ ssh jenkins@172.31.29.138
Last login: Fri Apr 12 04:31:49 2019

Step3: Add the agent from Jenkins UI

• On the Jenkins UI, Click on Manage Jenkins and then Manage Nodes

• Click on the New Node

* Name: Give your agent some name
* # of executors: The maximum number of concurrent builds that Jenkins may perform on this node.
* Remote root directory:An agent needs to have a directory dedicated to Jenkins. Specify the path to this directory on the agent. It is best to use   an absolute path, such as /var/jenkins or c:\jenkins.   This should be a path local to the agent machine. There is no need for this path to be visible from the master(/var/lib/jenkins/jenkins_build) created in earlier step
* Usage: Controls how Jenkins schedules builds on this node.                Use this node as much as possible - This is the default setting.       
In this mode, Jenkins uses this node freely. Whenever there is a build that can be done by using this node, Jenkins will use it.
* Credentials: Select the credentials to be used for logging in to the remote host.
* Host: Enter the hostname or IP address of your agent node in the Host field.

• Check if everything works

• To use the slave node

* 

* Restrict where this project can be run: Select the label we created in earlier step(jenkins_slave) this will make sure build run on agent host

• Run the job and you will see output like this

Looking forward from you guys to join this journey and spend a minimum an hour every day for the next 100 days on DevOps work and post your progress using any of the below medium.

• Twitter: @100daysofdevops OR @lakhera2015
• Facebook: https://www.facebook.com/groups/795382630808645/
• Medium: https://medium.com/@devopslearning
• Slack: https://devops-myworld.slack.com/messages/CF41EFG49/
• GitHub Link:https://github.com/100daysofdevops

Reference

100 Days of DevOps — Day 0