Run only the images you trust
Run only the images you trust¶
With UCP you can enforce applications to only use Docker images signed by UCP users you trust. Each time a user attempts to deploy an application to the cluster, UCP checks whether the application is using a trusted Docker image (and will halt the deployment if that is not the case).
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¶
- A developer makes changes to a service and pushes their changes to a version control system.
- A CI system creates a build, runs tests, and pushes an image to DTR with the new changes.
- The quality engineering team pulls the image and runs more tests. If everything looks good they sign and push the image.
- 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 trusted images:
Access the UCP UI and browse to the Admin Settings page.
In the left navigation pane, click Docker Content Trust.
Select the Run only signed images option.
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.
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.
At this point, UCP starts enforcing the policy. Existing services will continue running and can be restarted if needed, however UCP only allows the deployment of new services that use a trusted image.