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Private Docker registry authentication

Private Docker Registry authentication refers to the set of procedures and commands required to securely access and interact with private container image repositories. This process typically involves logging in to the registry via the command line interface using specific credentials and then tagging and pushing images to the private destination^[400-devops-03-containerization-docker.md].

Authentication Methods

Standard Registry Login

To authenticate with a private registry, the standard command structure requires specifying the registry URL alongside your username. For example, when logging into a specific hosted registry, the syntax involves the docker login command followed by the registry address and the username flag^[400-devops-03-containerization-docker.md].

docker login --username=username registry.example.com:5000

Upon execution, the system will prompt for a password^[400-devops-03-containerization-docker.md]. Once the credentials are verified, the terminal confirms the login success. It is worth noting that using a password grants complete terminal access to the account, and for enhanced security, the system recommends using a limited-privilege personal access token instead^[400-devops-03-containerization-docker.md].

Docker Hub Login

Authentication can also be performed directly against the default Docker Hub registry using the explicit registry-1.docker.io address^[400-devops-03-containerization-docker.md].

$ docker login registry-1.docker.io
Username: user
Password:
Login Succeeded

Workflow: Tagging and Pushing

After successfully logging in, pushing a local image to a private registry requires associating the local image with the remote registry's address through tagging^[400-devops-03-containerization-docker.md].

First, the local image ID or name is tagged with the target registry URL and the project path^[400-devops-03-containerization-docker.md]. Second, the docker push command is executed with that specific tag to upload the image^[400-devops-03-containerization-docker.md].

# Tag the image
$ docker tag <image_id> cloud.canister.io:5000/user/myapp

# Push the image
$ docker push cloud.canister.io:5000/user/myapp

The output of the push command provides feedback on the upload progress of individual image layers and concludes with a digest and size confirmation^[400-devops-03-containerization-docker.md].

Sources

^[400-devops-03-containerization-docker.md]