Change index removal reason when IndicesService is stopping

server/src/main/java/org/elasticsearch/indices/IndicesService.java

@@ -350,7 +350,7 @@ protected void doStop() {
         for (final Index index : indices) {
             indicesStopExecutor.execute(() -> {
                 try {
-                    removeIndex(index, IndexRemovalReason.NO_LONGER_ASSIGNED, "shutdown");
+                    removeIndex(index, IndexRemovalReason.SHUTDOWN, "shutdown");
                 } finally {
                     latch.countDown();
                 }

server/src/main/java/org/elasticsearch/indices/cluster/IndicesClusterStateService.java

@@ -950,6 +950,7 @@ enum IndexRemovalReason {
              * like the shards files, state and transaction logs are kept around in the case of a disaster recovery.
              */
             NO_LONGER_ASSIGNED,
+
             /**
              * The index is deleted. Persistent parts of the index  like the shards files, state and transaction logs are removed once
              * all resources are released.
@@ -974,6 +975,13 @@ enum IndexRemovalReason {
              * like the shards files, state and transaction logs are kept around in the case of a disaster recovery.
              */
             REOPENED,
+
+            /**
+             * The index is closed as part of the node shutdown process. The index should be removed and all associated resources released.
+             * Persistent parts of the index like the shards files, state and transaction logs should be kept around in the case the node
+             * restarts.
+             */
+            SHUTDOWN,
         }
     }
 }