I recently found out that Google Container Registry (GCR) doesn’t have yet a retention nor a cleanup feature. I quickly found two great open source contributions to accomplish this initiated by two Googlers:

  • gcr-cleaner
    • A containerized Golang app hosted on Cloud Run and triggered by Cloud Scheduler to delete untagged images.
  • gcrgc.sh
    • A bash script which will delete images before a specific date for a given container image.

Why I would like to cleanup my GCR? Good question. Different reasons actually, for example let’s imagine I have a lot of repositories and images in GCR, it may imply some costs even if GCR is not that expensive. Another reason is I would like to prevent someone to be able to pull and run a previous and old version of my container. Even worst, this old version could have security vulnerabilities…

FYI: here is a command line to get the size of a specific GCR:

gsutil du -hs gs://artifacts.$PROJECT_ID.appspot.com

Let’s execute the gcrgc.sh script from the second approach highlighted earlier:

curl https://gist.githubusercontent.com/ahmetb/7ce6d741bd5baa194a3fac6b1fec8bb7/raw/2a838649c037d6d7b3c7c52dffcd95176adf764b/gcrgc.sh -o gcrgc.sh
chmod +x gcrgc.sh
./gcrgc.sh gcr.io/$PROJECT_ID/$IMAGE_NAME 2020-08-01

You could also find altenative criteria to delete images, like for example here another way to see this by keeping only X number of images for a specific image name. You may also want to have this as a recurrent Cloud Build like illustrated here.

In other words, you could adapt these scripts for your own needs.