feat: pvc for wal (#122)

* feat: pvc for wal

* rename

Author: levkk

Chart.yaml

@@ -1,4 +1,4 @@
 apiVersion: v1
 name: pgdog
-version: v0.70
+version: v0.71
 appVersion: "0.1.47"

README.md

@@ -115,6 +115,28 @@ mirrors:
 
 ### High Availability
 
+#### StatefulSet WAL storage
+
+PgDog can persist its two-phase commit WAL when running as a StatefulSet.
+Enable `walPvc` and configure the requested capacity:
+
+```yaml
+statefulSet:
+  enabled: true
+  walPvc:
+    enabled: true
+    size: 5Gi
+```
+
+The StatefulSet creates one `ReadWriteOnce` persistent volume claim per replica
+and mounts it at `/var/lib/pgdog`. The generated PgDog configuration sets
+`two_phase_commit_wal_dir` to that mount point automatically. An explicit
+`twoPhaseCommitWalDir` value takes precedence.
+
+The claims use the cluster's default `StorageClass`. Ensure one is configured
+for dynamic provisioning before enabling `walPvc`. This option has no effect
+when PgDog runs as a Deployment.
+
 #### PodDisruptionBudget
 
 Ensures minimum pod availability during voluntary disruptions

templates/config.yaml

@@ -151,6 +151,8 @@ data:
         {{- end }}
         {{- if hasKey .Values "twoPhaseCommitWalDir" }}
         two_phase_commit_wal_dir  =   {{ .Values.twoPhaseCommitWalDir | quote }}
+        {{- else if and .Values.statefulSet.enabled .Values.statefulSet.walPvc.enabled }}
+        two_phase_commit_wal_dir  =   "/var/lib/pgdog"
         {{- end }}
         {{- if hasKey .Values "twoPhaseCommitWalSegmentSize" }}
         two_phase_commit_wal_segment_size      =   {{ include "pgdog.intval" .Values.twoPhaseCommitWalSegmentSize }}

templates/deployment.yaml

@@ -130,6 +130,10 @@ spec:
               mountPath: /etc/pgdog
             - name: users
               mountPath: /etc/secrets/pgdog
+            {{- if and .Values.statefulSet.enabled .Values.statefulSet.walPvc.enabled }}
+            - name: wal
+              mountPath: /var/lib/pgdog
+            {{- end }}
             {{- if .Values.tlsGenerateSelfSignedCert }}
             - name: tls
               mountPath: /etc/pgdog-tls
@@ -254,3 +258,14 @@ spec:
       topologySpreadConstraints:
         {{- toYaml . | nindent 8 }}
       {{- end }}
+  {{- if and .Values.statefulSet.enabled .Values.statefulSet.walPvc.enabled }}
+  volumeClaimTemplates:
+    - metadata:
+        name: wal
+      spec:
+        accessModes:
+          - ReadWriteOnce
+        resources:
+          requests:
+            storage: {{ .Values.statefulSet.walPvc.size | quote }}
+  {{- end }}

test/values-statefulset.yaml

@@ -1,3 +1,6 @@
 # Test StatefulSet deployment mode
 statefulSet:
   enabled: true
+  walPvc:
+    enabled: true
+    size: 5Gi

values.yaml

@@ -89,6 +89,12 @@ replicas: 2
 statefulSet:
   # enabled switches from Deployment to StatefulSet
   enabled: false
+  # walPvc creates one persistent volume claim per StatefulSet pod.
+  # The volume is mounted at /var/lib/pgdog. When enabled,
+  # twoPhaseCommitWalDir defaults to this mount point.
+  walPvc:
+    enabled: false
+    size: 1Gi
 
 # env allows setting custom environment variables on the pgdog container
 # Note: NODE_ID is automatically generated and cannot be overridden