Why Is Jenkins in Docker

The main reason is that Jenkins pipelines work really well with Docker. Without Docker you need to install additional tools and add different agents to Jenkins. With Docker, there is no need to install additional tools, you just use images of these tools.

How do Docker and Jenkins work together?

Jenkins builds a new docker image and pushes it to the Docker registry. Jenkins notifies Kubernetes of the new image available for deployment. Kubernetes pulls the new docker image from the docker registry. Kubernetes deploys and manages the docker instance/container.

What is the difference between Docker and Jenkins?

Docker is a container engine that can create and manage containers, whereas Jenkins is a CI engine that can run build/test on your app. Docker is used to build and run multiple portable environments of your software stack. Jenkins is an automated software testing tool for your app.