Managing Docker Image Trust

This post will cover topic related to ‘Managing Docker Image Trust’ with multiple docker command examples and different scenerios. So this will help you to understand the command docker and options available in it. Also this post will explain you how to use docker command.

Docker provides a robust mechanism for managing trust in Docker images, ensuring that only verified and trusted images are used in deployments. The docker trust command allows users to manage and manipulate cryptographic keys, sign images, and verify image signatures to establish a chain of trust within a Docker environment.

To illustrate the use of docker trust, consider the following examples:

1. Initialize Docker Trust:
To initialize Docker trust on your system, use:

docker trust key generate keyname

This command generates a new key pair for signing Docker images.
Verification: Check the existence of the generated key in your Docker configuration directory.

2. Sign an Image:
Sign an image using your key:

docker trust sign repository/image:tag

This signs an image to attest its integrity and authenticity.
Verification: Verify the image signature using:

docker trust inspect --pretty repository/image:tag

3. Revoke Trust:
Revoke trust from an image:

docker trust revoke repository/image:tag

This removes the signature and trust associated with the image.
Verification: Ensure the image no longer has a valid signature post-revocation.

4. List Trusted Publishers:
List all trusted publishers:

docker trust key list --dir directory

This displays all keys trusted for signing images.
Verification: Verify the list includes the expected keys used for signing.

5. Remove a Trust Key:
Remove a trust key from Docker:

docker trust key remove keyname

This deletes a key used for signing Docker images.
Verification: Confirm the key has been removed from the trust store.

6. Inspect Trust Data:
Inspect trust data for an image:

docker trust inspect repository/image:tag

This displays detailed trust metadata for the specified image.
Verification: Review the output to ensure the trust information matches expectations.

7. Enable Content Trust:
Enable content trust globally:

export DOCKER_CONTENT_TRUST=1

This ensures all Docker commands verify image signatures.
Verification: Run Docker commands and observe signature verification in action.

8. Disable Content Trust:
Disable content trust globally:

export DOCKER_CONTENT_TRUST=0

This disables signature verification for all Docker commands.
Verification: Confirm Docker commands no longer perform signature checks.

9. Initialize Remote Signing:
Initialize remote signing with a notary server:

docker trust key generate --dir directory --org organization

This sets up a remote signing configuration for an organization.
Verification: Verify the successful setup by checking the configuration files.

10. Delegate Signing:
Delegate signing to another key:

docker trust signer delegate keyname repository/image:tag

This allows another key to sign images on behalf of the specified key.
Verification: Confirm the delegation settings reflect the expected trust relationships.

Also check similar articles.

Managing Docker System
Managing Docker Plugins
Managing Docker Image Manifests and Lists
Managing Docker Images
Managing Docker Contexts