Add node local storage deprecation check (#54383)

The node.local_storage setting has been deprecated and will be removed
in 8.0.0. This commit adds a deprecation check to 7.x.

x-pack/plugin/deprecation/src/main/java/org/elasticsearch/xpack/deprecation/DeprecationChecks.java

@@ -48,7 +48,8 @@ public class DeprecationChecks {
             NodeDeprecationChecks::checkUniqueRealmOrders,
             (settings, pluginsAndModules) -> NodeDeprecationChecks.checkThreadPoolListenerQueueSize(settings),
             (settings, pluginsAndModules) -> NodeDeprecationChecks.checkThreadPoolListenerSize(settings),
-            NodeDeprecationChecks::checkClusterRemoteConnectSetting
+            NodeDeprecationChecks::checkClusterRemoteConnectSetting,
+            NodeDeprecationChecks::checkNodeLocalStorageSetting
         ));
 
     static List<Function<IndexMetaData, DeprecationIssue>> INDEX_SETTINGS_CHECKS =

x-pack/plugin/deprecation/src/main/java/org/elasticsearch/xpack/deprecation/NodeDeprecationChecks.java

@@ -129,6 +129,14 @@ class NodeDeprecationChecks {
         );
     }
 
+    public static DeprecationIssue checkNodeLocalStorageSetting(final Settings settings, final PluginsAndModules pluginsAndModules) {
+        return checkRemovedSetting(
+            settings,
+            Node.NODE_LOCAL_STORAGE_SETTING,
+            "https://www.elastic.co/guide/en/elasticsearch/reference/7.8/breaking-changes-7.8.html#deprecate-node-local-storage"
+        );
+    }
+
     private static DeprecationIssue checkDeprecatedSetting(
         final Settings settings,
         final PluginsAndModules pluginsAndModules,

x-pack/plugin/deprecation/src/test/java/org/elasticsearch/xpack/deprecation/NodeDeprecationChecksTests.java

@@ -199,6 +199,22 @@ public class NodeDeprecationChecksTests extends ESTestCase {
         assertSettingDeprecationsAndWarnings(new Setting<?>[]{RemoteClusterService.ENABLE_REMOTE_CLUSTERS});
     }
 
+    public void testNodeLocalStorageSetting() {
+        final boolean value = randomBoolean();
+        final Settings settings = Settings.builder().put(Node.NODE_LOCAL_STORAGE_SETTING.getKey(), value).build();
+        final PluginsAndModules pluginsAndModules = new PluginsAndModules(Collections.emptyList(), Collections.emptyList());
+        final List<DeprecationIssue> issues =
+            DeprecationChecks.filterChecks(DeprecationChecks.NODE_SETTINGS_CHECKS, c -> c.apply(settings, pluginsAndModules));
+        final DeprecationIssue expected = new DeprecationIssue(
+            DeprecationIssue.Level.CRITICAL,
+            "setting [node.local_storage] is deprecated and will be removed in the next major version",
+            "https://www.elastic.co/guide/en/elasticsearch/reference/7.8/breaking-changes-7.8.html#deprecate-node-local-storage",
+            "the setting [node.local_storage] is currently set to [" + value + "], remove this setting"
+        );
+        assertThat(issues, contains(expected));
+        assertSettingDeprecationsAndWarnings(new Setting<?>[]{Node.NODE_LOCAL_STORAGE_SETTING});
+    }
+
     public void testRemovedSettingNotSet() {
         final Settings settings = Settings.EMPTY;
         final Setting<?> removedSetting = Setting.simpleString("node.removed_setting");