Sinker

Garbage collector for old ProwJobs and Pods.

Sinker is Prow’s garbage-collector controller. It periodically removes old ProwJob resources and old/orphaned Pods created by Prow.

Source code: cmd/sinker

What Sinker Cleans Up

Sinker reconciles on a loop (sinker.resync_period) and:

  • Deletes completed non-periodic ProwJobs older than sinker.max_prowjob_age.
  • Deletes completed periodic ProwJobs older than sinker.max_prowjob_age, while keeping the latest run for active periodic jobs.
  • Deletes Prow Pods (label created-by-prow=true) when they are:
    • older than sinker.max_pod_age,
    • older than sinker.terminated_pod_ttl after their ProwJob completed,
    • orphaned (no matching ProwJob exists anymore).
  • Skips Pod cleanup in clusters listed in sinker.exclude_clusters.

Configuration (config.yaml)

Sinker behavior is controlled by the top-level sinker block in config.yaml:

sinker:
  resync_period: 1h
  max_prowjob_age: 168h
  max_pod_age: 24h
  terminated_pod_ttl: 24h
  exclude_clusters: []

Defaults:

  • resync_period: 1h
  • max_prowjob_age: 168h (7 days)
  • max_pod_age: 24h
  • terminated_pod_ttl: same as max_pod_age
  • exclude_clusters: empty

CLI Flags

Sinker-specific flags:

Flag Description Default
--run-once Run one reconciliation and exit. false
--dry-run Do not perform mutating Kubernetes API calls. true

Prow config loading flags:

Flag Description Default
--config-path Path to config.yaml (required). ""
--job-config-path Path to job config file or directory. ""
--supplemental-prow-config-dir Additional config directory (repeatable). none
--supplemental-prow-configs-filename Deprecated alias for suffix flag. "_prowconfig.yaml"
--supplemental-prow-configs-filename-suffix Filename suffix for supplemental configs. "_prowconfig.yaml"
--in-repo-config-cache-size Cache size for in-repo config loading. 200
--cache-dir-base Base directory for repo cache. ""
--moonraker-address Full HTTP address of Moonraker service. ""

Kubernetes client flags:

Flag Description Default
--kubeconfig Path to kubeconfig file. ""
--kubeconfig-dir Directory of kubeconfig files. ""
--kubeconfig-suffix Only load files with this suffix from --kubeconfig-dir. ""
--projected-token-file Projected service account token file for in-cluster auth. ""
--no-in-cluster-config Disable in-cluster config resolution. false

Instrumentation flags:

Flag Description Default
--metrics-port Port for Prometheus metrics endpoint. 9090
--pprof-port Port for pprof endpoints. 6060
--health-port Port for readiness/liveness endpoints. 8081
--profile-memory-usage Enable periodic memory profiling. false
--memory-profile-interval Interval between memory profiles. 30s

Notes

  • In production deployments, set --dry-run=false.
  • Sinker needs access to list/watch/get/delete/patch Pods in build clusters and manage ProwJob resources in the Prow namespace.

Last modified February 13, 2026: docs: replace sinker placeholder page with real component docs (6a695980c)