How to clean-up old unused Kubernetes images/tags?

kubernetes docker-registry google-kubernetes-engine
Wernight picture Wernight · Apr 4, 2016 · Viewed 24.2k times · Source

To simplify deployment and short term roll-back, it's useful to use a new Docker image tag for each new version to deploy on Kubernetes. Without clean-up this means that old images:tags are kept forever.

How can I list all image:tag that are used by a Kubernetes container so that I can find all old image:tag that are old and not used to delete them automatically from the Docker Registry?

My goal is ideally for Google Container Engine (GKE) to delete unused images a Google Container Registry.

Answer

Ryan Cox picture Ryan Cox · Apr 4, 2016

As an alternative approach, you might consider just letting Kubernetes handle reclamation of old images for you.

Presently, the ImageManager handles reclamation of candidate images. See: Garbage Collection

Garbage collection is a helpful function of kubelet that will clean up unreferenced images and unused containers. kubelet will perform garbage collection for containers every minute and garbage collection for images every five minutes.

Configuration is controlled via these two kublet cli parameters:

  --image-gc-high-threshold=90: The percent of disk usage after which image garbage collection is always run. Default: 90%
  --image-gc-low-threshold=80: The percent of disk usage before which image garbage collection is never run. Lowest disk usage to garbage collect to. Default: 80%

The high/low thresholds could be tuned to force collection at an interval that works for you.

Related questions

Why am I getting an ErrImagePull error in this Kubernetes deployment?

I'm trying to create a local Kubernetes deployment using Minikube, Docker Registry, and a demo node project. The first thing I did was install Docker v1.12.3, then Minikube v0.12.2. Then I created a Docker Registry container by running this command (…

Read More
kubernetes cannot pull local image

I am using kubernetes on a single machine for testing, I have built a custom image from the nginx docker image, but when I try to use the image in kubernetes I get an image pull error????? MY POD YAML …

Read More
Create kubernetes docker-registry secret from yaml file?

I can run this command to create a docker registry secret for a kubernetes cluster: kubectl create secret docker-registry regsecret \ --docker-server=docker.example.com \ --docker-username=kube \ --docker-password=PW_STRING \ [email protected] \ --namespace mynamespace I would like to create …

Read More