So, that "Hello World" job in previous blog zipped through in no time, right?
But let's face it, real pipelines are rarely that speedy.
They often involve downloading files from the internet, compiling source code, or running tests—tasks that can take anywhere from minutes to hours.
And let’s not even start on the beauty of concurrent pipelines. You know, when your whole team (or, heaven forbid, the entire organization) is using the same Jenkins instance.
The question is, how do we keep things running smoothly?
Master and Slaves
Surprisingly, Jenkins can become overloaded faster than you can say “continuous integration.” Even with a small microservice, a build can take a few minutes. Imagine one team committing code every five minutes—Jenkins would be gasping for air!
To prevent this from happening, it's best to let Jenkins do what it does best: Hand Over/ Transfer
Instead of executing builds directly, the Jenkins master should hand off the heavy lifting to the slave (or agent) instances.
So, while we're running the Jenkins master, it’s like the overworked manager who delegates tasks to the underlings.
In Jenkins' master-slave architecture, while slave nodes help offload the more resource-intensive tasks, the Jenkins master retains some critical responsibilities that cannot be delegated. These responsibilities ensure the proper functioning of the entire CI/CD process. Even with slave agents connected, the master handles certain jobs directly like:
- Receive Build Triggers: The Jenkins master monitors for new commits in the version control system (e.g., GitHub), activating build processes upon detecting changes.
- SCM Polling: master handles polling for Source Code Management (SCM) tools such as Git, SVN, or Perforce. SCM polling checks for code changes and triggers builds as needed.
- Build Output, Reporting, and Notifications: It generates alerts via email or chat applications (such as HipChat), particularly in cases of failure, ensuring timely communication.
- Handle HTTP Requests: The master processes incoming HTTP requests, facilitating interactions with clients and external systems to support various functionalities.
- Manage the Build Environment: It orchestrates the execution of jobs on the slave instances, coordinating resource allocation and job scheduling to optimize build performance and efficiency.
Understanding how to configure Jenkins agents is crucial for optimizing your CI/CD pipelines. For detailed guidance, you can refer to my article on:
Environmental Needs ?
Since the master and slaves have different roles, their environmental needs vary:
- Master: This is usually a dedicated machine. You should provision at least 200 MB of RAM for smaller projects, scaling up to 70 GB or more for large monolithic applications that demand significant resources.
- Slave: The requirements here are a bit more flexible. As long as it can execute a single build, it’s good to go.
It’s also wise to keep your agents as generic as possible. If you’ve got multiple projects—one in Java, another in Python, and yet another in Ruby—ideally, each agent should be able to handle any of these projects.
This way, you can interchange agents, optimizing resource usage and avoiding the dreaded bottleneck.
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As your projects expand, maintaining performance becomes crucial. Ready to take your Jenkins setup to the next level?
