Promote an image using policies

Estimated reading time: 3 minutes

Docker Trusted Registry allows you to create image promotion pipelines based on policies.

In this example we will create an image promotion pipeline such that:

  1. Developers iterate and push their builds to the dev/website repository.
  2. When the team creates a stable build, they make sure their image is tagged with -stable.
  3. When a stable build is pushed to the dev/website repository, it will automatically be promoted to qa/website so that the QA team can start testing.

With this promotion policy, the development team doesn’t need access to the QA repositories, and the QA team doesn’t need access to the development repositories.

promotion example

Configure your repository

Once you’ve created the repository, navigate to the repository page on the DTR web interface, and select the Promotions tab.

repository policies

Click New promotion policy, and define the image promotion criteria.

DTR allows you to set your promotion policy based on the following image attributes:

Name Description Example
Tag name Whether the tag name equals, starts with, ends with, contains, is one of, or is not one of your specified string values Promote to Target if Tag name ends in stable
Component name Whether the image has a given component and the component name equals, starts with, ends with, contains, is one of, or is not one of your specified string values Promote to Target if Component name starts with b
Vulnerabilities Whether the image has vulnerabilities – critical, major, minor, or all – and your selected vulnerability filter is greater than or equals, greater than, equals, not equals, less than or equals, or less than your specified number Promote to Target if Critical vulnerabilities = 3
License Whether the image uses an intellectual property license and is one of or not one of your specified words Promote to Target if License name = docker

Now you need to choose what happens to an image that meets all the criteria.

Select the target organization or namespace and repository where the image is going to be pushed. You can choose to keep the image tag, or transform the tag into something more meaningful in the destination repository, by using a tag template.

In this example, if an image in the dev/website is tagged with a word that ends in “stable”, DTR will automatically push that image to the qa/website repository. In the destination repository the image will be tagged with the timestamp of when the image was promoted.

repository with policies

Everything is set up! Once the development team pushes an image that complies with the policy, it automatically gets promoted. To confirm, select the Promotions tab on the dev/website repository.

tag promoted

You can also review the newly pushed tag in the target repository by navigating to qa/website and selecting the Tags tab.

tag promoted

Where to go next

registry, promotion, pipeline