feat: auto-trigger garbage collection after manifest cleanup

- Added automatic GC to prune script after deleting manifests
- Cronjob now uses python:3.12-slim with kubectl installed
- Added serviceAccountName: registry-gc-runner for permissions
- GC scales down registry, runs garbage-collect, scales back up
- Deletes unreferenced blob layers to actually free disk space

apps/registry/retention-cronjob.yaml

@@ -13,11 +13,20 @@ spec:
       backoffLimit: 1
       template:
         spec:
+          serviceAccountName: registry-gc-runner
           restartPolicy: Never
           containers:
             - name: prune
-              image: python:3.12-alpine
-              command: ["python", "/scripts/prune.py"]
+              image: python:3.12-slim
+              command: ["sh", "-c"]
+              args:
+                - |
+                  # Install kubectl
+                  apt-get update && apt-get install -y curl --no-install-recommends && rm -rf /var/lib/apt/lists/*
+                  curl -LO "https://dl.k8s.io/release/$(curl -L -s https://dl.k8s.io/release/stable.txt)/bin/linux/amd64/kubectl"
+                  install -o root -g root -m 0755 kubectl /usr/local/bin/kubectl
+                  # Run the prune script
+                  python3 /scripts/prune.py
               volumeMounts:
                 - name: script
                   mountPath: /scripts

apps/registry/retention-script.yaml

@@ -104,3 +104,81 @@ data:
           print(f'  delete failed {repo}:{t} err={e}')
 
     print(f'deleted_manifests={deleted}')
+
+    # Trigger garbage collection to delete unreferenced blob layers
+    if deleted > 0:
+      print('\n=== Triggering Garbage Collection ===')
+      try:
+        # Scale down registry to run GC
+        import subprocess
+        subprocess.run(['kubectl', 'scale', 'deployment', 'docker-registry', '--replicas=0', '-n', 'registry'], check=True)
+        print('Scaled down docker-registry deployment')
+        
+        # Wait for deployment to be fully down
+        import time
+        time.sleep(5)
+        
+        # Run GC job
+        gc_job = {
+          'apiVersion': 'batch/v1',
+          'kind': 'Job',
+          'metadata': {'name': 'registry-gc-once', 'namespace': 'registry'},
+          'spec': {
+            'backoffLimit': 0,
+            'template': {
+              'spec': {
+                'restartPolicy': 'Never',
+                'containers': [{
+                  'name': 'gc',
+                  'image': 'registry:3',
+                  'command': ['registry', 'garbage-collect', '--delete-untagged', '/etc/distribution/config.yml'],
+                  'volumeMounts': [
+                    {'name': 'storage', 'mountPath': '/var/lib/registry'},
+                    {'name': 'config', 'mountPath': '/etc/distribution'}
+                  ]
+                }],
+                'volumes': [
+                  {'name': 'storage', 'persistentVolumeClaim': {'claimName': 'registry-pvc'}},
+                  {'name': 'config', 'configMap': {'name': 'registry-config'}}
+                ]
+              }
+            }
+          }
+        }
+        
+        # Delete old GC job if exists
+        subprocess.run(['kubectl', 'delete', 'job', 'registry-gc-once', '-n', 'registry', '--ignore-not-found=true'], check=False)
+        time.sleep(2)
+        
+        # Create and wait for GC job
+        import tempfile
+        with tempfile.NamedTemporaryFile(mode='w', suffix='.json', delete=False) as f:
+          json.dump(gc_job, f)
+          f.flush()
+          subprocess.run(['kubectl', 'apply', '-f', f.name], check=True)
+        
+        print('GC job created, waiting for completion...')
+        
+        # Wait up to 10 minutes for GC to complete
+        for i in range(120):
+          result = subprocess.run(['kubectl', 'get', 'job', 'registry-gc-once', '-n', 'registry', '-o', 'jsonpath={.status.succeeded}'], capture_output=True, text=True)
+          if result.stdout.strip() == '1':
+            print('Garbage collection completed successfully')
+            break
+          result = subprocess.run(['kubectl', 'get', 'job', 'registry-gc-once', '-n', 'registry', '-o', 'jsonpath={.status.failed}'], capture_output=True, text=True)
+          if result.stdout.strip() == '1':
+            print('GC job failed')
+            break
+          time.sleep(5)
+        
+        # Scale back up
+        subprocess.run(['kubectl', 'scale', 'deployment', 'docker-registry', '--replicas=1', '-n', 'registry'], check=True)
+        print('Scaled up docker-registry deployment')
+        
+      except Exception as e:
+        print(f'GC trigger failed: {e}')
+        # Ensure registry is scaled back up even if GC failed
+        try:
+          subprocess.run(['kubectl', 'scale', 'deployment', 'docker-registry', '--replicas=1', '-n', 'registry'], check=False)
+        except:
+          pass