When do we need to have slaves for Jenkins and when we do not?

Question

I am a beginner user of Jenkins. I am trying to putting a development process onto the DevOps pipeline that includes Jenkins, GitHub, SonarQube, IBM UCD.

It is not a very complicated deployment process and it uses windows machine.

There are three environments, QA, DEV, and PROD.

I know that I need to install one IBM UCD agent for each of those three, but do I need to have three slaves in Jenkins as well , or just one master in Jenkins could do that deployment for three environments ? Which way is better ?

Answer 1

Usually for the complex deployment process companies are using "Master+Agent" scheme, but in your case there is no need to create some advanced Jenkins system with master and agents if you can build it on one host and you have not any additional projects or restrictions.

From official documentation:

It is pretty common when starting with Jenkins to have a single server which runs the master and all builds, however Jenkins architecture is fundamentally "Master+Agent". The master is designed to do co-ordination and provide the GUI and API endpoints, and the Agents are designed to perform the work. The reason being that workloads are often best "farmed out" to distributed servers. This may be for scale, or to provide different tools, or build on different target platforms. Another common reason for remote agents is to enact deployments into secured environments (without the master having direct access).

For additional information you can read the following articles: this and this.