YARN-10829. Support getApplications API in FederationClientInterceptor (#3135)

YARN-10829. Support getApplications API in FederationClientInterceptor (#3135)

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-api/src/main/java/org/apache/hadoop/yarn/api/protocolrecords/GetApplicationsResponse.java

@@ -18,6 +18,8 @@
 
 package org.apache.hadoop.yarn.api.protocolrecords;
 
+import java.util.ArrayList;
+import java.util.Collection;
 import java.util.List;
 
 import org.apache.hadoop.classification.InterfaceAudience.Private;
@@ -52,6 +54,16 @@ public abstract class GetApplicationsResponse {
     return response;
   }
 
+  @Private
+  @Unstable
+  public static GetApplicationsResponse newInstance(
+      Collection<ApplicationReport> applications) {
+    GetApplicationsResponse response =
+        Records.newRecord(GetApplicationsResponse.class);
+    response.setApplicationList(new ArrayList<>(applications));
+    return response;
+  }
+
   /**
    * Get <code>ApplicationReport</code> for applications.
    * @return <code>ApplicationReport</code> for applications

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-api/src/main/java/org/apache/hadoop/yarn/conf/YarnConfiguration.java

@@ -3991,6 +3991,15 @@ public class YarnConfiguration extends Configuration {
       ROUTER_PREFIX + "submit.retry";
   public static final int DEFAULT_ROUTER_CLIENTRM_SUBMIT_RETRY = 3;
 
+  /**
+   * The interceptor class used in FederationClientInterceptor should return
+   * partial ApplicationReports.
+   */
+  public static final String ROUTER_CLIENTRM_PARTIAL_RESULTS_ENABLED =
+          ROUTER_PREFIX + "partial-result.enabled";
+  public static final boolean DEFAULT_ROUTER_CLIENTRM_PARTIAL_RESULTS_ENABLED =
+          false;
+
   public static final String ROUTER_WEBAPP_PREFIX = ROUTER_PREFIX + "webapp.";
 
   public static final String ROUTER_USER_CLIENT_THREADS_SIZE =

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-api/src/test/java/org/apache/hadoop/yarn/conf/TestYarnConfigurationFields.java

@@ -184,6 +184,8 @@ public class TestYarnConfigurationFields extends TestConfigurationFieldsBase {
 
     configurationPrefixToSkipCompare
         .add(YarnConfiguration.ROUTER_CLIENTRM_SUBMIT_RETRY);
+    configurationPrefixToSkipCompare
+        .add(YarnConfiguration.ROUTER_CLIENTRM_PARTIAL_RESULTS_ENABLED);
     configurationPrefixToSkipCompare
         .add(YarnConfiguration.ROUTER_WEBAPP_PARTIAL_RESULTS_ENABLED);
     configurationPrefixToSkipCompare

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-router/src/main/java/org/apache/hadoop/yarn/server/router/clientrm/FederationClientInterceptor.java

@@ -22,6 +22,7 @@ import org.apache.hadoop.thirdparty.com.google.common.util.concurrent.ThreadFact
 import java.io.IOException;
 import java.lang.reflect.Method;
 import java.util.ArrayList;
+import java.util.Collection;
 import java.util.List;
 import java.util.Map;
 import java.util.Random;
@@ -161,6 +162,7 @@ public class FederationClientInterceptor
   private RouterMetrics routerMetrics;
   private ThreadPoolExecutor executorService;
   private final Clock clock = new MonotonicClock();
+  private boolean returnPartialReport;
 
   @Override
   public void init(String userName) {
@@ -196,6 +198,10 @@ public class FederationClientInterceptor
     clientRMProxies =
         new ConcurrentHashMap<SubClusterId, ApplicationClientProtocol>();
     routerMetrics = RouterMetrics.getMetrics();
+
+    returnPartialReport = conf.getBoolean(
+        YarnConfiguration.ROUTER_CLIENTRM_PARTIAL_RESULTS_ENABLED,
+        YarnConfiguration.DEFAULT_ROUTER_CLIENTRM_PARTIAL_RESULTS_ENABLED);
   }
 
   @Override
@@ -599,10 +605,44 @@ public class FederationClientInterceptor
     return response;
   }
 
+  /**
+   * The Yarn Router will forward the request to all the Yarn RMs in parallel,
+   * after that it will group all the ApplicationReports by the ApplicationId.
+   *
+   * Possible failure:
+   *
+   * Client: identical behavior as {@code ClientRMService}.
+   *
+   * Router: the Client will timeout and resubmit the request.
+   *
+   * ResourceManager: the Router calls each Yarn RM in parallel. In case a
+   * Yarn RM fails, a single call will timeout. However the Router will
+   * merge the ApplicationReports it got, and provides a partial list to
+   * the client.
+   *
+   * State Store: the Router will timeout and it will retry depending on the
+   * FederationFacade settings - if the failure happened before the select
+   * operation.
+   */
   @Override
   public GetApplicationsResponse getApplications(GetApplicationsRequest request)
       throws YarnException, IOException {
-    throw new NotImplementedException("Code is not implemented");
+    if (request == null) {
+      RouterServerUtil.logAndThrowException(
+          "Missing getApplications request.",
+          null);
+    }
+    Map<SubClusterId, SubClusterInfo> subclusters =
+        federationFacade.getSubClusters(true);
+    ClientMethod remoteMethod = new ClientMethod("getApplications",
+        new Class[] {GetApplicationsRequest.class}, new Object[] {request});
+    Map<SubClusterId, GetApplicationsResponse> applications =
+        invokeConcurrent(subclusters.keySet(), remoteMethod,
+            GetApplicationsResponse.class);
+
+    // Merge the Application Reports
+    return RouterYarnClientUtils.mergeApplications(applications.values(),
+        returnPartialReport);
   }
 
   @Override
@@ -676,6 +716,12 @@ public class FederationClientInterceptor
     return results;
   }
 
+  <R> Map<SubClusterId, R> invokeConcurrent(Collection<SubClusterId> clusterIds,
+      ClientMethod request, Class<R> clazz) throws YarnException, IOException {
+    ArrayList<SubClusterId> clusterIdList = new ArrayList<>(clusterIds);
+    return invokeConcurrent(clusterIdList, request, clazz);
+  }
+
   @Override
   public GetClusterNodesResponse getClusterNodes(GetClusterNodesRequest request)
       throws YarnException, IOException {

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-router/src/main/java/org/apache/hadoop/yarn/server/router/clientrm/RouterYarnClientUtils.java

@@ -18,14 +18,25 @@
 package org.apache.hadoop.yarn.server.router.clientrm;
 
 import java.util.Collection;
+import java.util.HashMap;
+import java.util.Map;
+
+import org.apache.hadoop.yarn.api.protocolrecords.GetApplicationsResponse;
 import org.apache.hadoop.yarn.api.protocolrecords.GetClusterMetricsResponse;
+import org.apache.hadoop.yarn.api.records.ApplicationId;
+import org.apache.hadoop.yarn.api.records.ApplicationReport;
+import org.apache.hadoop.yarn.api.records.ApplicationResourceUsageReport;
 import org.apache.hadoop.yarn.api.records.YarnClusterMetrics;
+import org.apache.hadoop.yarn.server.uam.UnmanagedApplicationManager;
+import org.apache.hadoop.yarn.util.resource.Resources;
 
 /**
  * Util class for Router Yarn client API calls.
  */
 public final class RouterYarnClientUtils {
 
+  private final static String PARTIAL_REPORT = "Partial Report ";
+
   private RouterYarnClientUtils() {
 
   }
@@ -52,4 +63,130 @@ public final class RouterYarnClientUtils {
     }
     return GetClusterMetricsResponse.newInstance(tmp);
   }
+
+  /**
+   * Merges a list of ApplicationReports grouping by ApplicationId.
+   * Our current policy is to merge the application reports from the reachable
+   * SubClusters.
+   * @param responses a list of ApplicationResponse to merge
+   * @param returnPartialResult if the merge ApplicationReports should contain
+   * partial result or not
+   * @return the merged ApplicationsResponse
+   */
+  public static GetApplicationsResponse mergeApplications(
+      Collection<GetApplicationsResponse> responses,
+      boolean returnPartialResult){
+    Map<ApplicationId, ApplicationReport> federationAM = new HashMap<>();
+    Map<ApplicationId, ApplicationReport> federationUAMSum = new HashMap<>();
+
+    for (GetApplicationsResponse appResponse : responses){
+      for (ApplicationReport appReport : appResponse.getApplicationList()){
+        ApplicationId appId = appReport.getApplicationId();
+        // Check if this ApplicationReport is an AM
+        if (!appReport.isUnmanagedApp()) {
+          // Insert in the list of AM
+          federationAM.put(appId, appReport);
+          // Check if there are any UAM found before
+          if (federationUAMSum.containsKey(appId)) {
+            // Merge the current AM with the found UAM
+            mergeAMWithUAM(appReport, federationUAMSum.get(appId));
+            // Remove the sum of the UAMs
+            federationUAMSum.remove(appId);
+          }
+          // This ApplicationReport is an UAM
+        } else if (federationAM.containsKey(appId)) {
+          // Merge the current UAM with its own AM
+          mergeAMWithUAM(federationAM.get(appId), appReport);
+        } else if (federationUAMSum.containsKey(appId)) {
+          // Merge the current UAM with its own UAM and update the list of UAM
+          ApplicationReport mergedUAMReport =
+              mergeUAMWithUAM(federationUAMSum.get(appId), appReport);
+          federationUAMSum.put(appId, mergedUAMReport);
+        } else {
+          // Insert in the list of UAM
+          federationUAMSum.put(appId, appReport);
+        }
+      }
+    }
+    // Check the remaining UAMs are depending or not from federation
+    for (ApplicationReport appReport : federationUAMSum.values()) {
+      if (mergeUamToReport(appReport.getName(), returnPartialResult)) {
+        federationAM.put(appReport.getApplicationId(), appReport);
+      }
+    }
+
+    return GetApplicationsResponse.newInstance(federationAM.values());
+  }
+
+  private static ApplicationReport mergeUAMWithUAM(ApplicationReport uam1,
+      ApplicationReport uam2){
+    uam1.setName(PARTIAL_REPORT + uam1.getApplicationId());
+    mergeAMWithUAM(uam1, uam2);
+    return uam1;
+  }
+
+  private static void mergeAMWithUAM(ApplicationReport am,
+      ApplicationReport uam){
+    ApplicationResourceUsageReport amResourceReport =
+        am.getApplicationResourceUsageReport();
+
+    ApplicationResourceUsageReport uamResourceReport =
+        uam.getApplicationResourceUsageReport();
+
+    amResourceReport.setNumUsedContainers(
+        amResourceReport.getNumUsedContainers() +
+            uamResourceReport.getNumUsedContainers());
+
+    amResourceReport.setNumReservedContainers(
+        amResourceReport.getNumReservedContainers() +
+            uamResourceReport.getNumReservedContainers());
+
+    amResourceReport.setUsedResources(Resources.add(
+        amResourceReport.getUsedResources(),
+        uamResourceReport.getUsedResources()));
+
+    amResourceReport.setReservedResources(Resources.add(
+        amResourceReport.getReservedResources(),
+        uamResourceReport.getReservedResources()));
+
+    amResourceReport.setNeededResources(Resources.add(
+        amResourceReport.getNeededResources(),
+        uamResourceReport.getNeededResources()));
+
+    amResourceReport.setMemorySeconds(
+        amResourceReport.getMemorySeconds() +
+            uamResourceReport.getMemorySeconds());
+
+    amResourceReport.setVcoreSeconds(
+        amResourceReport.getVcoreSeconds() +
+            uamResourceReport.getVcoreSeconds());
+
+    amResourceReport.setQueueUsagePercentage(
+        amResourceReport.getQueueUsagePercentage() +
+            uamResourceReport.getQueueUsagePercentage());
+
+    amResourceReport.setClusterUsagePercentage(
+        amResourceReport.getClusterUsagePercentage() +
+            uamResourceReport.getClusterUsagePercentage());
+
+    am.setApplicationResourceUsageReport(amResourceReport);
+  }
+
+  /**
+   * Returns whether or not to add an unmanaged application to the report.
+   * @param appName Application Name
+   * @param returnPartialResult if the merge ApplicationReports should contain
+   * partial result or not
+   */
+  private static boolean mergeUamToReport(String appName,
+      boolean returnPartialResult){
+    if (returnPartialResult) {
+      return true;
+    }
+    if (appName == null) {
+      return false;
+    }
+    return !(appName.startsWith(UnmanagedApplicationManager.APP_NAME) ||
+        appName.startsWith(PARTIAL_REPORT));
+  }
 }

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-router/src/test/java/org/apache/hadoop/yarn/server/router/clientrm/TestFederationClientInterceptor.java

@@ -22,16 +22,20 @@ import static org.mockito.Mockito.mock;
 
 import java.io.IOException;
 import java.util.ArrayList;
+import java.util.Collections;
+import java.util.EnumSet;
 import java.util.List;
-
 import java.util.Map;
+import java.util.Set;
 
 import org.apache.hadoop.test.LambdaTestUtils;
 import org.apache.hadoop.yarn.MockApps;
-import org.apache.hadoop.yarn.api.protocolrecords.GetApplicationReportRequest;
-import org.apache.hadoop.yarn.api.protocolrecords.GetApplicationReportResponse;
 import org.apache.hadoop.yarn.api.protocolrecords.GetApplicationAttemptReportRequest;
 import org.apache.hadoop.yarn.api.protocolrecords.GetApplicationAttemptReportResponse;
+import org.apache.hadoop.yarn.api.protocolrecords.GetApplicationReportRequest;
+import org.apache.hadoop.yarn.api.protocolrecords.GetApplicationReportResponse;
+import org.apache.hadoop.yarn.api.protocolrecords.GetApplicationsRequest;
+import org.apache.hadoop.yarn.api.protocolrecords.GetApplicationsResponse;
 import org.apache.hadoop.yarn.api.protocolrecords.GetClusterMetricsRequest;
 import org.apache.hadoop.yarn.api.protocolrecords.GetClusterMetricsResponse;
 import org.apache.hadoop.yarn.api.protocolrecords.GetNewApplicationRequest;
@@ -40,11 +44,12 @@ import org.apache.hadoop.yarn.api.protocolrecords.KillApplicationRequest;
 import org.apache.hadoop.yarn.api.protocolrecords.KillApplicationResponse;
 import org.apache.hadoop.yarn.api.protocolrecords.SubmitApplicationRequest;
 import org.apache.hadoop.yarn.api.protocolrecords.SubmitApplicationResponse;
-import org.apache.hadoop.yarn.api.records.ApplicationId;
 import org.apache.hadoop.yarn.api.records.ApplicationAttemptId;
+import org.apache.hadoop.yarn.api.records.ApplicationId;
 import org.apache.hadoop.yarn.api.records.ApplicationSubmissionContext;
 import org.apache.hadoop.yarn.api.records.ContainerLaunchContext;
 import org.apache.hadoop.yarn.api.records.Priority;
+import org.apache.hadoop.yarn.api.records.YarnApplicationState;
 import org.apache.hadoop.yarn.conf.YarnConfiguration;
 import org.apache.hadoop.yarn.exceptions.YarnException;
 import org.apache.hadoop.yarn.server.federation.policies.manager.UniformBroadcastPolicyManager;
@@ -531,4 +536,109 @@ public class TestFederationClientInterceptor extends BaseRouterClientRMTest {
             GetClusterMetricsResponse.class);
     Assert.assertEquals(true, clusterMetrics.isEmpty());
   }
+
+  /**
+   * This test validates the correctness of
+   * GetApplicationsResponse in case the
+   * application exists in the cluster.
+   */
+  @Test
+  public void testGetApplicationsResponse()
+      throws YarnException, IOException, InterruptedException {
+    LOG.info("Test FederationClientInterceptor: Get Applications Response");
+    ApplicationId appId =
+        ApplicationId.newInstance(System.currentTimeMillis(), 1);
+
+    SubmitApplicationRequest request = mockSubmitApplicationRequest(appId);
+    SubmitApplicationResponse response = interceptor.submitApplication(request);
+
+    Assert.assertNotNull(response);
+    Assert.assertNotNull(stateStoreUtil.queryApplicationHomeSC(appId));
+
+    Set<String> appTypes = Collections.singleton("MockApp");
+    GetApplicationsRequest requestGet =
+        GetApplicationsRequest.newInstance(appTypes);
+
+    GetApplicationsResponse responseGet =
+        interceptor.getApplications(requestGet);
+
+    Assert.assertNotNull(responseGet);
+  }
+
+  /**
+   * This test validates
+   * the correctness of GetApplicationsResponse in case of
+   * empty request.
+   */
+  @Test
+  public void testGetApplicationsNullRequest() throws Exception {
+    LOG.info("Test FederationClientInterceptor: Get Applications request");
+    LambdaTestUtils.intercept(YarnException.class,
+        "Missing getApplications request.",
+        () -> interceptor.getApplications(null));
+  }
+
+  /**
+   * This test validates
+   * the correctness of GetApplicationsResponse in case applications
+   * with given type does not exist.
+   */
+  @Test
+  public void testGetApplicationsApplicationTypeNotExists() throws Exception{
+    LOG.info("Test FederationClientInterceptor: Application with type does "
+        + "not exist");
+
+    ApplicationId appId =
+        ApplicationId.newInstance(System.currentTimeMillis(), 1);
+
+    SubmitApplicationRequest request = mockSubmitApplicationRequest(appId);
+    SubmitApplicationResponse response = interceptor.submitApplication(request);
+
+    Assert.assertNotNull(response);
+    Assert.assertNotNull(stateStoreUtil.queryApplicationHomeSC(appId));
+
+    Set<String> appTypes = Collections.singleton("SPARK");
+
+    GetApplicationsRequest requestGet =
+        GetApplicationsRequest.newInstance(appTypes);
+
+    GetApplicationsResponse responseGet =
+        interceptor.getApplications(requestGet);
+
+    Assert.assertNotNull(responseGet);
+    Assert.assertTrue(responseGet.getApplicationList().isEmpty());
+  }
+
+  /**
+   * This test validates
+   * the correctness of GetApplicationsResponse in case applications
+   * with given YarnApplicationState does not exist.
+   */
+  @Test
+  public void testGetApplicationsApplicationStateNotExists() throws Exception{
+    LOG.info("Test FederationClientInterceptor:" +
+        " Application with state does not exist");
+
+    ApplicationId appId =
+        ApplicationId.newInstance(System.currentTimeMillis(), 1);
+
+    SubmitApplicationRequest request = mockSubmitApplicationRequest(appId);
+    SubmitApplicationResponse response = interceptor.submitApplication(request);
+
+    Assert.assertNotNull(response);
+    Assert.assertNotNull(stateStoreUtil.queryApplicationHomeSC(appId));
+
+    EnumSet<YarnApplicationState> applicationStates = EnumSet.noneOf(
+        YarnApplicationState.class);
+    applicationStates.add(YarnApplicationState.KILLED);
+
+    GetApplicationsRequest requestGet =
+        GetApplicationsRequest.newInstance(applicationStates);
+
+    GetApplicationsResponse responseGet =
+        interceptor.getApplications(requestGet);
+
+    Assert.assertNotNull(responseGet);
+    Assert.assertTrue(responseGet.getApplicationList().isEmpty());
+  }
 }

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-router/src/test/java/org/apache/hadoop/yarn/server/router/clientrm/TestRouterYarnClientUtils.java

@@ -19,8 +19,19 @@
 package org.apache.hadoop.yarn.server.router.clientrm;
 
 import java.util.ArrayList;
+import java.util.List;
+
+import org.apache.hadoop.yarn.api.protocolrecords.GetApplicationsResponse;
 import org.apache.hadoop.yarn.api.protocolrecords.GetClusterMetricsResponse;
+import org.apache.hadoop.yarn.api.records.ApplicationAttemptId;
+import org.apache.hadoop.yarn.api.records.ApplicationId;
+import org.apache.hadoop.yarn.api.records.ApplicationReport;
+import org.apache.hadoop.yarn.api.records.ApplicationResourceUsageReport;
+import org.apache.hadoop.yarn.api.records.FinalApplicationStatus;
+import org.apache.hadoop.yarn.api.records.Resource;
+import org.apache.hadoop.yarn.api.records.YarnApplicationState;
 import org.apache.hadoop.yarn.api.records.YarnClusterMetrics;
+import org.apache.hadoop.yarn.server.uam.UnmanagedApplicationManager;
 import org.junit.Assert;
 import org.junit.Test;
 
@@ -29,6 +40,8 @@ import org.junit.Test;
  */
 public class TestRouterYarnClientUtils {
 
+  private final static String PARTIAL_REPORT = "Partial Report ";
+
   @Test
   public void testClusterMetricsMerge() {
     ArrayList<GetClusterMetricsResponse> responses = new ArrayList<>();
@@ -54,4 +67,108 @@ public class TestRouterYarnClientUtils {
     metrics.setNumNodeManagers(value);
     return GetClusterMetricsResponse.newInstance(metrics);
   }
+
+  /**
+   * This test validates the correctness of
+   * RouterYarnClientUtils#mergeApplications.
+   */
+  @Test
+  public void testMergeApplications() {
+    ArrayList<GetApplicationsResponse> responses = new ArrayList<>();
+    responses.add(getApplicationsResponse(1, false));
+    responses.add(getApplicationsResponse(2, false));
+    GetApplicationsResponse result = RouterYarnClientUtils.
+        mergeApplications(responses, false);
+    Assert.assertNotNull(result);
+    Assert.assertEquals(2, result.getApplicationList().size());
+
+    String appName1 = result.getApplicationList().get(0).getName();
+    String appName2 = result.getApplicationList().get(1).getName();
+
+    // Check that no Unmanaged applications are added to the result
+    Assert.assertEquals(false,
+        appName1.contains(UnmanagedApplicationManager.APP_NAME));
+    Assert.assertEquals(false,
+        appName2.contains(UnmanagedApplicationManager.APP_NAME));
+  }
+
+  /**
+   * This test validates the correctness of
+   * RouterYarnClientUtils#mergeApplications.
+   */
+  @Test
+  public void testMergeUnmanagedApplications() {
+    ArrayList<GetApplicationsResponse> responses = new ArrayList<>();
+    responses.add(getApplicationsResponse(1, true));
+
+    // Check response if partial results are enabled
+    GetApplicationsResponse result = RouterYarnClientUtils.
+        mergeApplications(responses, true);
+    Assert.assertNotNull(result);
+    Assert.assertEquals(1, result.getApplicationList().size());
+    ApplicationReport appReport = result.getApplicationList().iterator().next();
+    String appName = appReport.getName();
+    Assert.assertTrue(appName.startsWith(PARTIAL_REPORT));
+
+    // Check ApplicationResourceUsageReport merge
+    ApplicationResourceUsageReport resourceUsageReport =
+        appReport.getApplicationResourceUsageReport();
+
+    Assert.assertEquals(2, resourceUsageReport.getNumUsedContainers());
+    Assert.assertEquals(4, resourceUsageReport.getNumReservedContainers());
+
+    // Check response if partial results are disabled
+    result = RouterYarnClientUtils.
+        mergeApplications(responses, false);
+    Assert.assertNotNull(result);
+    Assert.assertTrue(result.getApplicationList().isEmpty());
+  }
+
+  /**
+   * This generates a GetApplicationsResponse with 2 applications with
+   * same ApplicationId.
+   * @param value Used as Id in ApplicationId
+   * @param uamOnly If set to true, only unmanaged applications are added in
+   *                response, else one managed and one unmanaged applications
+   *                are added with same ApplicationId.
+   * @return GetApplicationsResponse
+   */
+  private GetApplicationsResponse getApplicationsResponse(int value,
+      boolean uamOnly) {
+    String appName = uamOnly? UnmanagedApplicationManager.APP_NAME: "appname";
+    List<ApplicationReport> applications = new ArrayList<>();
+
+    // Create first application report. This is a managed app by default.
+    // If uamOnly is true, this becomes unmanaged application.
+    ApplicationId appId = ApplicationId.newInstance(1234, value);
+    Resource resource = Resource.newInstance(1024, 1);
+    ApplicationResourceUsageReport appResourceUsageReport =
+        ApplicationResourceUsageReport.newInstance(
+            1, 2, resource, resource,
+            resource, null, 0.1f,
+            0.1f, null);
+
+    ApplicationReport appReport = ApplicationReport.newInstance(
+        appId, ApplicationAttemptId.newInstance(appId, 1),
+        "user", "queue", appName, "host",
+        124, null, YarnApplicationState.RUNNING,
+        "diagnostics", "url", 0, 0,
+        0, FinalApplicationStatus.SUCCEEDED, appResourceUsageReport, "N/A",
+        0.53789f, "YARN", null, null, uamOnly, null, null, null);
+
+    // Create second application report. This is always unmanaged application.
+    ApplicationId appId2 = ApplicationId.newInstance(1234, value);
+    ApplicationReport appReport2 = ApplicationReport.newInstance(
+        appId2, ApplicationAttemptId.newInstance(appId, 1),
+        "user", "queue", UnmanagedApplicationManager.APP_NAME, "host",
+        124, null, YarnApplicationState.RUNNING,
+        "diagnostics", "url", 0, 0,
+        0, FinalApplicationStatus.SUCCEEDED, appResourceUsageReport, "N/A",
+        0.53789f, "YARN", null, null, true, null, null, null);
+
+    applications.add(appReport);
+    applications.add(appReport2);
+
+    return GetApplicationsResponse.newInstance(applications);
+  }
 }