YARN-8278. DistributedScheduling is not working in HA. Contributed by Bibin A Chundatt.

(Cherry picked from commit 2bb647bb91439e82cf7298e963bb5f7f80bbc3cb)

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-common/src/main/java/org/apache/hadoop/yarn/server/api/ServerRMProxy.java

@@ -34,6 +34,11 @@ public class ServerRMProxy<T> extends RMProxy<T> {
   private static final Logger LOG =
       LoggerFactory.getLogger(ServerRMProxy.class);
 
+  private interface ServerRMProtocols
+      extends DistributedSchedulingAMProtocol, ResourceTracker {
+    //Add nothing
+  }
+
   private ServerRMProxy() {
     super();
   }
@@ -95,8 +100,8 @@ public class ServerRMProxy<T> extends RMProxy<T> {
   @InterfaceAudience.Private
   @Override
   public void checkAllowedProtocols(Class<?> protocol) {
-    Preconditions.checkArgument(
-        protocol.isAssignableFrom(ResourceTracker.class),
-        "ResourceManager does not support this protocol");
+    Preconditions
+        .checkArgument(protocol.isAssignableFrom(ServerRMProtocols.class),
+            "ResourceManager does not support this protocol");
   }
 }

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-common/src/test/java/org/apache/hadoop/yarn/server/api/TestServerRMProxy.java

@@ -0,0 +1,52 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.hadoop.yarn.server.api;
+
+import org.apache.hadoop.yarn.conf.HAUtil;
+import org.apache.hadoop.yarn.conf.YarnConfiguration;
+import org.junit.Assert;
+import org.junit.Test;
+
+/**
+ * Test ServerRMProxy.
+ */
+public class TestServerRMProxy {
+
+  @Test
+  public void testDistributedProtocol() {
+
+    YarnConfiguration conf = new YarnConfiguration();
+    try {
+      ServerRMProxy.createRMProxy(conf, DistributedSchedulingAMProtocol.class);
+    } catch (Exception e) {
+      Assert.fail("DistributedSchedulingAMProtocol fail in non HA");
+    }
+
+    // HA is enabled
+    conf.setBoolean(YarnConfiguration.RM_HA_ENABLED, true);
+    conf.set(YarnConfiguration.RM_HA_IDS, "rm1,rm2");
+    conf.set(HAUtil.addSuffix(YarnConfiguration.RM_HOSTNAME, "rm1"), "0.0.0.0");
+    conf.set(HAUtil.addSuffix(YarnConfiguration.RM_HOSTNAME, "rm2"), "0.0.0.0");
+    try {
+      ServerRMProxy.createRMProxy(conf, DistributedSchedulingAMProtocol.class);
+    } catch (Exception e) {
+      Assert.fail("DistributedSchedulingAMProtocol fail in HA");
+    }
+  }
+}