Pulling from private registries in Docker - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is a private Docker registry?

A private Docker registry is a secure place where you can store and share Docker images only with authorized users, unlike public registries which are open to everyone.

beginner

How do you authenticate Docker to pull images from a private registry?

You use the command docker login <registry_url> and enter your username and password to authenticate Docker with the private registry.

beginner

What command pulls an image from a private Docker registry after login?

Use docker pull <registry_url>/<image_name>:<tag> to pull the image from the private registry.

intermediate

Why might you get a 'denied: requested access to the resource is denied' error when pulling from a private registry?

This error usually means you are not logged in or do not have permission to access the image in the private registry.

beginner

What is the purpose of the docker logout command?

It removes your saved login credentials for a registry, so Docker will no longer authenticate automatically with that registry.

Which command do you use to authenticate Docker with a private registry?

A docker login <registry_url>

B docker pull <image_name>

C docker build <Dockerfile>

D docker logout

You must use 'docker login ' to provide your credentials before pulling images from a private registry.

What happens if you try to pull an image from a private registry without logging in?

A Docker shows an access denied error.

B Docker pulls the image successfully.

C Docker deletes the image.

D Docker automatically logs in.

Without login, Docker cannot authenticate and will deny access to private images.

How do you specify the private registry when pulling an image?

A docker pull <image_name>

B docker push <image_name>

C docker pull <registry_url>/<image_name>

D docker build <image_name>

You must include the registry URL before the image name to pull from a private registry.

What is the effect of running 'docker logout <registry_url>'?

A It updates Docker to the latest version.

B It logs you out from the Docker Hub only.

C It deletes all images from your local machine.

D It removes saved credentials for the specified registry.

'docker logout ' removes your saved login credentials for that registry.

Which of these is NOT a reason to use a private Docker registry?

A To share images only with authorized users.

B To publicly share images with everyone.

C To keep images secure and private.

D To control access to your Docker images.

Public sharing is the purpose of public registries, not private ones.

Explain the steps to pull a Docker image from a private registry.

Think about authentication first, then pulling the image.

Describe common errors when pulling from private registries and how to fix them.

Focus on authentication and command syntax.