Enable local sessions in ZK when readonly mode is enabled (#655)

Author: lhotari

charts/pulsar/templates/zookeeper-configmap.yaml

@@ -42,5 +42,9 @@ data:
   PULSAR_PREFIX_serverCnxnFactory: org.apache.zookeeper.server.NIOServerCnxnFactory
   serverCnxnFactory: org.apache.zookeeper.server.NIOServerCnxnFactory
   {{- end }}
+  {{- if .Values.pulsar_metadata.metadataStoreAllowReadOnlyOperations }}
+  PULSAR_PREFIX_localSessionsEnabled: "true"
+  PULSAR_PREFIX_localSessionsUpgradingEnabled: "true"
+  {{- end }}
 {{ toYaml .Values.zookeeper.configData | indent 2 }}
 {{- end }}

charts/pulsar/values.yaml

@@ -1025,6 +1025,7 @@ pulsar_metadata:
 
   ## Allow read-only operations on the metadata store when the metadata store is not available.
   ## This is useful when you want to continue serving requests even if the metadata store is not fully available with quorum.
+  ## NOTICE: This mode is not recommended for production use and no tests exist to validate the behavior.
   metadataStoreAllowReadOnlyOperations: false
 
   ## The session timeout for the metadata store in milliseconds.