Question
You have noticed that Docker and Jenkins are regularly used together. Why is this?
Answer
1. The docker build command produces one artifact. Jenkins lends itself to well-defined tasks.
2. The logic and dependencies of the build can usually be completely contained in the Dockerfile (page 20 of Docker Up and Running). Simple lines of text can standardize many aspects of a given build (e.g., Java) (page 20 of Docker Up and Running). This can be shared company-wide (page 20 of Docker Up and Running). Deployments are consistent and simple which is excellent for testing. A big part of the CI/CD pipeline is testing. Lower environments are made for testing before production. The concept of Docker is a container that is transportable like a whale (Docker's icon).