Pruning images using CronJob

This example shows an image pruning happening in an automated fashion using the Kubernetes CronJobs. In this example, we will create a CronJob that will run image pruning every 1 hour.

Requirements

In order to execute the pruning commands successfully, it is necessary to create a dedicated service account image-pruner with necessary privileges to perform pruning against the entire cluster. Make sure you run below commands with a user who has the power to assign cluster roles. Also double check the namespace you are invoking them in, if it is the one you desire.

1. oc create serviceaccount image-pruner

   This command creates an image-pruner service account.

2. oc adm policy add-cluster-role-to-user system:image-pruner image-pruner

   This command grants the image-pruner role to that service account.

Creating the CronJob

2. oc create -f examples/pruner/cronjob.yaml -n default --kubeconfig=admin.kubeconfig

   This command creates the CronJob resource that runs the pruning job every 1 hour.

Make sure, that you check the oc adm prune --help command and optionally tweak the CronJob arguments by specifying how much tag revisions you want to preserve on a single tag or other options that might suit your environment. Full details about pruning images can be found in the official documentation.