Run only the images you trust

Estimated reading time: 2 minutes

This topic applies to Docker Enterprise.

The Docker Enterprise platform business, including products, customers, and employees, has been acquired by Mirantis, inc., effective 13-November-2019. For more information on the acquisition and how it may affect you and your business, refer to the Docker Enterprise Customer FAQ.

With Docker Universal Control Plane you can enforce applications to only use Docker images signed by UCP users you trust. When a user tries to deploy an application to the cluster, UCP checks if the application uses a Docker image that is not trusted, and won’t continue with the deployment if that’s the case.

Enforce image signing

By signing and verifying the Docker images, you ensure that the images being used in your cluster are the ones you trust and haven’t been altered either in the image registry or on their way from the image registry to your UCP cluster.

Example workflow

Here’s an example of a typical workflow:

  1. A developer makes changes to a service and pushes their changes to a version control system.
  2. A CI system creates a build, runs tests, and pushes an image to DTR with the new changes.
  3. The quality engineering team pulls the image and runs more tests. If everything looks good they sign and push the image.
  4. The IT operations team deploys a service. If the image used for the service was signed by the QA team, UCP deploys it. Otherwise UCP refuses to deploy.

Configure UCP

To configure UCP to only allow running services that use Docker images you trust, go to the UCP web UI, navigate to the Admin Settings page, and in the left pane, click Docker Content Trust.

Select the Run Only Signed Images option to only allow deploying applications if they use images you trust.

UCP settings

With this setting, UCP allows deploying any image as long as the image has been signed. It doesn’t matter who signed the image.

To enforce that the image needs to be signed by specific teams, click Add Team and select those teams from the list.

UCP settings

If you specify multiple teams, the image needs to be signed by a member of each team, or someone that is a member of all those teams.

Click Save for UCP to start enforcing the policy. From now on, existing services will continue running and can be restarted if needed, but UCP will only allow deploying new services that use a trusted image.

Where to go next

ucp, dtr, security, trust