fix(spark): replace shared spark-events PVC with emptyDir to fix Multi-Attach error

local-path provisioner is RWO-only; attaching a single PVC to master, two
workers, history-server, and streaming pod on separate nodes causes
Multi-Attach errors. Each pod now gets its own ephemeral emptyDir for
/spark-events. Event logging confs removed from CronJobs and streaming
Deployment (logs are pod-local and do not persist across restarts).

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

spark-cluster/base/history-server.yaml

@@ -40,8 +40,7 @@ spec:
               mountPath: /spark-events
       volumes:
         - name: spark-events
-          persistentVolumeClaim:
-            claimName: spark-events
+          emptyDir: {}
 ---
 apiVersion: v1
 kind: Service

spark-cluster/base/master.yaml

@@ -42,8 +42,7 @@ spec:
               mountPath: /spark-events
       volumes:
         - name: spark-events
-          persistentVolumeClaim:
-            claimName: spark-events
+          emptyDir: {}
 ---
 apiVersion: v1
 kind: Service

spark-cluster/base/pvc.yaml

@@ -1,18 +1,5 @@
-apiVersion: v1
-kind: PersistentVolumeClaim
-metadata:
-  name: spark-events
-  labels:
-    app.kubernetes.io/name: spark-cluster
-    app.kubernetes.io/part-of: nowchess
-spec:
-  # ReadWriteOnce for k3d/local-path compatibility.
-  # NOTE: k3d uses the local-path provisioner which only supports RWO.
-  # For production with multiple concurrent writers (workers + history server),
-  # replace with a RWX-capable storage class such as NFS or Longhorn and
-  # change accessModes to [ReadWriteMany].
-  accessModes:
-    - ReadWriteOnce
-  resources:
-    requests:
-      storage: 5Gi
+# No cluster-level PVCs needed.
+# Analytics output and streaming checkpoint PVCs live in spark-analytics/base/pvc.yaml.
+# spark-events PVC removed: local-path provisioner is RWO-only; sharing a single PVC
+# across master, workers, and history-server on different nodes causes Multi-Attach errors.
+# Event logs now use emptyDir (pod-local, ephemeral) on each pod.

spark-cluster/base/workers.yaml

@@ -43,5 +43,4 @@ spec:
               mountPath: /spark-events
       volumes:
         - name: spark-events
-          persistentVolumeClaim:
-            claimName: spark-events
+          emptyDir: {}