Building images in CI pipeline in Docker - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is the main purpose of building Docker images in a CI pipeline?

To automate the creation of consistent, tested application environments that can be deployed reliably.

beginner

Which file usually contains the instructions to build a Docker image?

The Dockerfile contains step-by-step instructions to build a Docker image.

beginner

Name a common CI tool that can be used to build Docker images automatically.

Jenkins, GitHub Actions, GitLab CI, and CircleCI are popular CI tools that support Docker image builds.

intermediate

Why is it important to tag Docker images in a CI pipeline?

Tagging helps identify image versions clearly, making it easier to deploy specific builds and track changes.

beginner

What command is used in a CI script to build a Docker image from a Dockerfile?

The command is: docker build -t image_name:tag .

What does the command 'docker build -t myapp:latest .' do in a CI pipeline?

A Pushes the Docker image 'myapp:latest' to a registry

B Runs a Docker container named 'myapp' with the tag 'latest'

C Builds a Docker image named 'myapp' with the tag 'latest' from the current directory

D Deletes the Docker image named 'myapp:latest'

The 'docker build' command creates an image from the Dockerfile in the current directory, tagging it as 'myapp:latest'.

Why should Docker images be built in a CI pipeline rather than manually?

A Because manual builds are faster

B To ensure consistent, repeatable builds and automate testing

C To avoid using Dockerfiles

D To skip testing steps

CI pipelines automate builds to make sure they are consistent and tested every time code changes.

Which file must be present in the project root for Docker to build an image?

A Dockerfile

B docker-compose.yml

C README.md

D build.sh

Dockerfile contains the instructions needed to build the Docker image.

In a CI pipeline, what is a common next step after building a Docker image?

A Push the image to a Docker registry

B Delete the image immediately

C Run the image without testing

D Ignore the image

Pushing the image to a registry makes it available for deployment or sharing.

What is the benefit of using tags like 'latest' or version numbers on Docker images in CI?

A They prevent image building

B They make images run faster

C They delete old images automatically

D They help track and deploy specific image versions

Tags identify image versions clearly, aiding deployment and rollback.

Explain the steps to build and push a Docker image in a CI pipeline.

Think about how automation helps create and share images.

Why is automating Docker image builds in CI important for software delivery?

Consider benefits of automation and reliability.