fix: remove PVC patch that broke kubectl apply on bound claims

The mysql-data-pvc was already dynamically provisioned by the cluster's
'local-path' StorageClass. The overlay patch tried to change storageClassName
to 'manual' and volumeName on an already-bound PVC, which Kubernetes forbids:
  "spec is immutable after creation except resources.requests"

Fixes:
- Remove mysql-pvc-patch from kustomization.yaml (PVC left as-is)
- Remove mysql-pv.yaml resource (not needed with dynamic provisioner)
- Add comment explaining when manual PV/PVC is needed vs not

Jenkinsfile: add --timeout and FQDN to smoke test curl; add comments
explaining MySQL Recreate strategy startup timing expectations.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Jenkinsfile

@@ -115,11 +115,18 @@ pipeline {
                 withKubeConfig([credentialsId: "${K8S_CRED_ID}"]) {
                     sh "kubectl apply -k ${K8S_OVERLAY}"
 
+                    // MySQL uses Recreate strategy: old pod terminates (~30s) before
+                    // new pod starts. Readiness probe initialDelaySeconds=30 + up to
+                    // 10 retries × 5s = 80s. Total worst-case: ~110s → 300s is safe.
                     sh "kubectl rollout status deployment/mysql   -n scrum-manager --timeout=300s"
+
+                    // Backend initContainer sleeps 15s after MySQL TCP is up before
+                    // starting the Node process. 300s covers slow-start scenarios.
                     sh "kubectl rollout status deployment/backend  -n scrum-manager --timeout=300s"
+
                     sh "kubectl rollout status deployment/frontend -n scrum-manager --timeout=180s"
 
-                    echo "✅ All deployments rolled out."
+                    echo "All deployments rolled out."
                 }
             }
         }
@@ -127,14 +134,18 @@ pipeline {
         stage('Smoke Test') {
             steps {
                 withKubeConfig([credentialsId: "${K8S_CRED_ID}"]) {
+                    // Run a curl pod inside the cluster to hit the backend health endpoint.
+                    // Uses FQDN (backend.scrum-manager.svc.cluster.local) to be explicit.
                     sh """
                         kubectl run smoke-${BUILD_NUMBER} \
-                            --image=curlimages/curl:latest \
+                            --image=curlimages/curl:8.5.0 \
                             --restart=Never \
                             --rm \
                             --attach \
+                            --timeout=30s \
                             -n scrum-manager \
-                            -- curl -sf http://backend:3001/api/health \
+                            -- curl -sf --max-time 10 \
+                               http://backend.scrum-manager.svc.cluster.local:3001/api/health \
                         && echo "Health check PASSED" \
                         || echo "Health check FAILED (non-blocking)"
                     """

k8s/overlays/on-premise/kustomization.yaml

@@ -19,11 +19,10 @@ resources:
   - ../../base
   - ingress.yaml
 
-patches:
-  - path: mysql-pvc-patch.yaml
-    target:
-      kind: PersistentVolumeClaim
-      name: mysql-data-pvc
+# NOTE: mysql-pv.yaml and mysql-pvc-patch.yaml are only needed on clusters
+# without a default StorageClass. This cluster uses 'local-path' (dynamic
+# provisioner), so the base PVC works as-is and must NOT be patched after
+# it is already bound.
 
 images:
   - name: scrum-frontend

k8s/overlays/on-premise/mysql-pv.yaml

@@ -1,29 +0,0 @@
-apiVersion: v1
-kind: PersistentVolume
-metadata:
-  name: mysql-pv
-  labels:
-    type: local
-spec:
-  storageClassName: manual
-  capacity:
-    storage: 5Gi
-  accessModes:
-    - ReadWriteOnce
-  persistentVolumeReclaimPolicy: Retain
-  hostPath:
-    path: "/mnt/data/mysql"
-    # DirectoryOrCreate: kubelet will create the dir if it doesn't exist,
-    # preventing MySQL CrashLoopBackOff due to missing mount path.
-    type: DirectoryOrCreate
-  # IMPORTANT for multi-node clusters: uncomment nodeAffinity and set your
-  # node's hostname so MySQL always schedules on the node that has the data.
-  # Run: kubectl get nodes  to find the hostname.
-  # nodeAffinity:
-  #   required:
-  #     nodeSelectorTerms:
-  #       - matchExpressions:
-  #           - key: kubernetes.io/hostname
-  #             operator: In
-  #             values:
-  #               - YOUR-NODE-HOSTNAME