YARN-8062. yarn rmadmin -getGroups returns group from which the user has been removed. (Sunil G via wangda)

Change-Id: I80ed63846502bf7751b890b6c6c6a7c0679e2b4a
(cherry picked from commit 5d381570f83022b411a8740d58486a7f68ab2af6)
(cherry picked from commit 54da6a0d78c7832d647831b73030a1f75db932a9)

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/main/java/org/apache/hadoop/yarn/server/resourcemanager/ResourceManager.java

@@ -253,9 +253,8 @@ public class ResourceManager extends CompositeService implements Recoverable {
     // load core-site.xml
     loadConfigurationXml(YarnConfiguration.CORE_SITE_CONFIGURATION_FILE);
 
-    // Do refreshUserToGroupsMappings with loaded core-site.xml
-    Groups.getUserToGroupsMappingServiceWithLoadedConfiguration(this.conf)
-        .refresh();
+    // Refresh user to group mappings during init.
+    refreshUserToGroupMappingsWithConf();
 
     // Do refreshSuperUserGroupsConfiguration with loaded core-site.xml
     // Or use RM specific configurations to overwrite the common ones first
@@ -340,6 +339,21 @@ public class ResourceManager extends CompositeService implements Recoverable {
     super.serviceInit(this.conf);
   }
 
+  private void refreshUserToGroupMappingsWithConf()
+      throws YarnException, IOException {
+    Configuration newConf = new Configuration(false);
+    InputStream confFileInputStream =
+        configurationProvider
+        .getConfigurationInputStream(newConf, YarnConfiguration.CORE_SITE_CONFIGURATION_FILE);
+    if (confFileInputStream != null) {
+      newConf.addResource(confFileInputStream);
+    }
+
+    // Do refreshUserToGroupsMappings with loaded core-site.xml
+    Groups.getUserToGroupsMappingServiceWithLoadedConfiguration(newConf)
+        .refresh();
+  }
+
   private void loadConfigurationXml(String configurationFile)
       throws YarnException, IOException {
     InputStream configurationInputStream =