Pushing images from CI in Docker - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is the main purpose of pushing Docker images from a CI pipeline?

To automatically upload built Docker images to a container registry so they can be used in deployment or shared with others.

beginner

Which command is used to push a Docker image to a registry?

The command is docker push <image-name>. It uploads the image to the specified registry.

beginner

Why do you need to log in to a Docker registry in your CI pipeline before pushing images?

Logging in authenticates the pipeline with the registry, allowing it to upload images securely and preventing unauthorized access.

intermediate

What environment variables are commonly used in CI pipelines for Docker registry authentication?

Variables like DOCKER_USERNAME and DOCKER_PASSWORD or tokens are used to store credentials securely.

intermediate

How can tagging Docker images in CI help with version control?

Tagging images with build numbers, commit hashes, or version numbers helps identify and deploy specific image versions easily.

What is the first step before pushing a Docker image in a CI pipeline?

A Logging in to the Docker registry

B Running docker push command

C Building the Docker image

D Tagging the Docker image

You must log in to the Docker registry first to authenticate before pushing images.

Which command tags a Docker image with a version before pushing?

A docker login

B docker push image:tag

C docker tag source-image target-image:tag

D docker build -t image:tag

The docker tag command assigns a tag to an existing image.

Why is it important to use environment variables for Docker credentials in CI?

A To speed up the build process

B To keep credentials secure and not hard-coded in scripts

C To avoid logging in to the registry

D To automatically build images

Environment variables protect sensitive data by not exposing credentials in code.

What happens if you try to push a Docker image without logging in first?

A Image will push successfully

B Docker will build the image automatically

C Image will be deleted

D Push will fail with an authentication error

Without login, the registry denies access and push fails.

Which of these is a common container registry where images can be pushed?

A Docker Hub

B GitHub

C Jenkins

D Travis CI

Docker Hub is a popular public container registry for storing Docker images.

Explain the steps to push a Docker image from a CI pipeline.

Think about what happens from building to uploading the image.

Why is tagging Docker images important in continuous integration workflows?

Consider how you keep track of different builds.