As part of the Continuous Integration process, new builds are generated which contains certain enhancements or modification or bugfixes. For a containerized application deployment, docker images are created as part of builds which then needs to be uploaded to one of the container registries. Over the time, the registry will get filled up. Also as one use more and more space on the container registry, one needs to pay more and more.

There are no inbuilt commands or utilities provided by Docker for this. You have to write complex scripts for doing it. Fortunately, in latest round of the Azure CLI update, Microsoft has added some commands to do this. However, it can be cumbersome to select and remove docker images one at a time. 

To overcome this problem, we have written a PowerShell script to do this for all repos in a automated manner. This script can also be made part of some kind of scheduler to run it at defined frequency. The instructions to configure script as a scheduled job, will vary depending on type of scheduler and so they cannot be covered.

Code for same can be downloaded from repo:

https://github.com/goyalmohit/acr-cleanup