Configure garbage collection for the Knative revisions

This topic tells you about current Garbage collection defaults for Knative Revisions and you can update them in Tanzu Application Platform.

Overview

You can configure garbage collection with Knative. For more information, see the Knative documentation.

The current configuration sets the following defaults to mark Knative revisions for garbage collection:

  * `retain-since-create-time: "48h"`: Any revision created with an age of 2 days is considered for garbage collection.
  * `retain-since-last-active-time: "15h"`: Revision that was last active at least 15 hours ago is considered for garbage collection.
  * `min-non-active-revisions: "2"`: The minimum number of inactive Revisions to retain.
  * `max-non-active-revisions: "5"`: The maximum number of inactive Revisions to retain.

Update default values for Knative Garbage Collection

To update default values for Knative Garbage Collection:

1. Create an overlay with the following contents:

   apiVersion: v1
   kind: Secret
   metadata:
    name: cnr-overlay-gc-cm
    namespace: tap-install #! namespace where tap is installed
   stringData:
    overlay-gc-cm.yaml: |
      #@ load("@ytt:overlay", "overlay")
      #@overlay/match by=overlay.subset({"kind":"ConfigMap","metadata":{"name":"config-gc"}})
      ---
      data:
        #@overlay/match missing_ok=True
        retain-since-create-time: "48h"
        #@overlay/match missing_ok=True
        retain-since-last-active-time: "15h"
        #@overlay/match missing_ok=True
        min-non-active-revisions: "2"
        #@overlay/match missing_ok=True
        max-non-active-revisions: "5"
   

2. Update Tanzu Application Platform values.

   package_overlays:
    - name: cnrs
      secrets:
        - name: cnr-overlay-gc-cm
   

3. Update Tanzu Application Platform Package.

   tanzu package installed update tap -p tap.tanzu.vmware.com --values-file tap-values.YAML  -n tap-install
   

4. Verify that the overlay was applied by running following commands:

   kubectl get configmap config-gc --namespace knative-serving --output jsonpath="{.data.retain-since-create-time}"
   kubectl get configmap config-gc --namespace knative-serving --output jsonpath="{.data.retain-since-last-active-time}"
   kubectl get configmap config-gc --namespace knative-serving --output jsonpath="{.data.min-non-active-revisions}"
   kubectl get configmap config-gc --namespace knative-serving --output jsonpath="{.data.max-non-active-revisions}"