YARN-8145. yarn rmadmin -getGroups doesn't return updated groups for user. Contributed by Sunil G.

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

@@ -34,7 +34,6 @@ import org.apache.hadoop.metrics2.MetricsSystem;
 import org.apache.hadoop.metrics2.lib.DefaultMetricsSystem;
 import org.apache.hadoop.metrics2.source.JvmMetrics;
 import org.apache.hadoop.net.NetUtils;
-import org.apache.hadoop.security.Groups;
 import org.apache.hadoop.security.SecurityUtil;
 import org.apache.hadoop.security.UserGroupInformation;
 import org.apache.hadoop.security.authorize.ProxyUsers;
@@ -254,9 +253,6 @@ public class ResourceManager extends CompositeService implements Recoverable {
     // load core-site.xml
     loadConfigurationXml(YarnConfiguration.CORE_SITE_CONFIGURATION_FILE);
 
-    // 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
     // if they exist
@@ -340,21 +336,6 @@ 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 =

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/test/java/org/apache/hadoop/yarn/server/resourcemanager/TestRMAdminService.java

@@ -722,6 +722,7 @@ public class TestRMAdminService {
     }
 
     // Make sure RM will use the updated GroupMappingServiceProvider
+    Groups.getUserToGroupsMappingServiceWithLoadedConfiguration(conf).refresh();
     List<String> groupBefore =
         new ArrayList<String>(Groups.getUserToGroupsMappingService(
             configuration).getGroups(user));
@@ -1099,6 +1100,7 @@ public class TestRMAdminService {
           .get("hadoop.proxyuser.test.hosts").contains("test_hosts"));
 
       // verify UserToGroupsMappings
+      Groups.getUserToGroupsMappingServiceWithLoadedConfiguration(conf).refresh();
       List<String> groupAfter =
           Groups.getUserToGroupsMappingService(configuration).getGroups(
               UserGroupInformation.getCurrentUser().getUserName());