Examples with HeldContainer org.apache.tez.dag.app.rm.YarnTaskSchedulerService.HeldContainer used on opensource projects

Example 1 with HeldContainer

use of org.apache.tez.dag.app.rm.YarnTaskSchedulerService.HeldContainer in project tez by apache.

the class TestTaskScheduler method testTaskSchedulerPreemption.

@SuppressWarnings({ "unchecked", "rawtypes" })
@Test(timeout = 5000)
public void testTaskSchedulerPreemption() throws Exception {
    TezAMRMClientAsync<CookieContainerRequest> mockRMClient = mock(TezAMRMClientAsync.class);
    Configuration conf = new Configuration();
    conf.setBoolean(TezConfiguration.TEZ_AM_CONTAINER_REUSE_ENABLED, false);
    conf.setInt(TezConfiguration.TEZ_AM_PREEMPTION_HEARTBEATS_BETWEEN_PREEMPTIONS, 3);
    TaskSchedulerContext mockApp = setupMockTaskSchedulerContext(DEFAULT_APP_HOST, DEFAULT_APP_PORT, DEFAULT_APP_URL, false, null, null, new PreemptionMatcher(), conf);
    final TaskSchedulerContextDrainable drainableAppCallback = createDrainableContext(mockApp);
    final TaskSchedulerWithDrainableContext scheduler = new TaskSchedulerWithDrainableContext(drainableAppCallback, mockRMClient);
    scheduler.initialize();
    RegisterApplicationMasterResponse mockRegResponse = mock(RegisterApplicationMasterResponse.class);
    when(mockRMClient.registerApplicationMaster(anyString(), anyInt(), anyString())).thenReturn(mockRegResponse);
    scheduler.start();
    Resource totalResource = Resource.newInstance(4000, 4);
    when(mockRMClient.getAvailableResources()).thenReturn(totalResource);
    // no preemption
    scheduler.getProgress();
    drainableAppCallback.drain();
    Assert.assertEquals(totalResource, scheduler.getTotalResources());
    verify(mockRMClient, times(0)).releaseAssignedContainer((ContainerId) any());
    // allocate task
    Object mockTask1 = mock(Object.class);
    Object mockTask2 = mock(Object.class);
    Object mockTask3 = mock(Object.class);
    Object mockTask3Wait = mock(Object.class);
    Object mockTask3Retry = mock(Object.class);
    Object mockTask3KillA = mock(Object.class);
    Object mockTask3KillB = mock(Object.class);
    Object mockTaskPri8 = mock(Object.class);
    Object obj3 = new Object();
    Priority pri2 = Priority.newInstance(2);
    Priority pri4 = Priority.newInstance(4);
    Priority pri5 = Priority.newInstance(5);
    Priority pri6 = Priority.newInstance(6);
    Priority pri8 = Priority.newInstance(8);
    ArgumentCaptor<CookieContainerRequest> requestCaptor = ArgumentCaptor.forClass(CookieContainerRequest.class);
    final ArrayList<CookieContainerRequest> anyContainers = new ArrayList<CookieContainerRequest>();
    Resource taskAsk = Resource.newInstance(1024, 1);
    scheduler.allocateTask(mockTask1, taskAsk, null, null, pri2, null, null);
    drainableAppCallback.drain();
    verify(mockRMClient, times(1)).addContainerRequest(requestCaptor.capture());
    anyContainers.add(requestCaptor.getValue());
    scheduler.allocateTask(mockTask3, taskAsk, null, null, pri6, obj3, null);
    drainableAppCallback.drain();
    verify(mockRMClient, times(2)).addContainerRequest(requestCaptor.capture());
    anyContainers.add(requestCaptor.getValue());
    // later one in the allocation gets killed between the two task3's
    scheduler.allocateTask(mockTask3KillA, taskAsk, null, null, pri6, obj3, null);
    drainableAppCallback.drain();
    verify(mockRMClient, times(3)).addContainerRequest(requestCaptor.capture());
    anyContainers.add(requestCaptor.getValue());
    // later one in the allocation gets killed between the two task3's
    scheduler.allocateTask(mockTask3KillB, taskAsk, null, null, pri6, obj3, null);
    drainableAppCallback.drain();
    verify(mockRMClient, times(4)).addContainerRequest(requestCaptor.capture());
    anyContainers.add(requestCaptor.getValue());
    Resource freeResource = Resource.newInstance(500, 0);
    when(mockRMClient.getAvailableResources()).thenReturn(freeResource);
    scheduler.getProgress();
    drainableAppCallback.drain();
    Assert.assertEquals(totalResource, scheduler.getTotalResources());
    verify(mockRMClient, times(0)).releaseAssignedContainer((ContainerId) any());
    final List<ArrayList<CookieContainerRequest>> anyList = new LinkedList<ArrayList<CookieContainerRequest>>();
    final List<ArrayList<CookieContainerRequest>> emptyList = new LinkedList<ArrayList<CookieContainerRequest>>();
    anyList.add(anyContainers);
    List<Container> containers = new ArrayList<Container>();
    Container mockContainer1 = mock(Container.class, RETURNS_DEEP_STUBS);
    when(mockContainer1.getNodeId().getHost()).thenReturn("host1");
    when(mockContainer1.getResource()).thenReturn(taskAsk);
    when(mockContainer1.getPriority()).thenReturn(pri2);
    ContainerId mockCId1 = mock(ContainerId.class);
    when(mockContainer1.getId()).thenReturn(mockCId1);
    containers.add(mockContainer1);
    Container mockContainer2 = mock(Container.class, RETURNS_DEEP_STUBS);
    when(mockContainer2.getNodeId().getHost()).thenReturn("host1");
    when(mockContainer2.getResource()).thenReturn(taskAsk);
    when(mockContainer2.getPriority()).thenReturn(pri6);
    ContainerId mockCId2 = mock(ContainerId.class);
    when(mockContainer2.getId()).thenReturn(mockCId2);
    containers.add(mockContainer2);
    Container mockContainer3A = mock(Container.class, RETURNS_DEEP_STUBS);
    when(mockContainer3A.getNodeId().getHost()).thenReturn("host1");
    when(mockContainer3A.getResource()).thenReturn(taskAsk);
    when(mockContainer3A.getPriority()).thenReturn(pri6);
    ContainerId mockCId3A = mock(ContainerId.class);
    when(mockContainer3A.getId()).thenReturn(mockCId3A);
    containers.add(mockContainer3A);
    Container mockContainer3B = mock(Container.class, RETURNS_DEEP_STUBS);
    when(mockContainer3B.getNodeId().getHost()).thenReturn("host1");
    when(mockContainer3B.getResource()).thenReturn(taskAsk);
    // high priority container
    when(mockContainer3B.getPriority()).thenReturn(pri2);
    ContainerId mockCId3B = mock(ContainerId.class);
    when(mockContainer3B.getId()).thenReturn(mockCId3B);
    containers.add(mockContainer3B);
    when(mockRMClient.getMatchingRequests((Priority) any(), eq("host1"), (Resource) any())).thenAnswer(new Answer<List<? extends Collection<CookieContainerRequest>>>() {

        @Override
        public List<? extends Collection<CookieContainerRequest>> answer(InvocationOnMock invocation) throws Throwable {
            return emptyList;
        }
    });
    // RackResolver by default puts hosts in default-rack
    when(mockRMClient.getMatchingRequests((Priority) any(), eq("/default-rack"), (Resource) any())).thenAnswer(new Answer<List<? extends Collection<CookieContainerRequest>>>() {

        @Override
        public List<? extends Collection<CookieContainerRequest>> answer(InvocationOnMock invocation) throws Throwable {
            return emptyList;
        }
    });
    when(mockRMClient.getMatchingRequests((Priority) any(), eq(ResourceRequest.ANY), (Resource) any())).thenAnswer(new Answer<List<? extends Collection<CookieContainerRequest>>>() {

        int calls = 0;

        @Override
        public List<? extends Collection<CookieContainerRequest>> answer(InvocationOnMock invocation) throws Throwable {
            if (calls > 0) {
                anyContainers.remove(0);
            }
            calls++;
            return anyList;
        }
    });
    Mockito.doAnswer(new Answer() {

        public Object answer(InvocationOnMock invocation) {
            Object[] args = invocation.getArguments();
            ContainerId cId = (ContainerId) args[0];
            scheduler.deallocateContainer(cId);
            return null;
        }
    }).when(mockApp).preemptContainer((ContainerId) any());
    scheduler.onContainersAllocated(containers);
    drainableAppCallback.drain();
    Assert.assertEquals(4, scheduler.taskAllocations.size());
    Assert.assertEquals(4096, scheduler.allocatedResources.getMemory());
    Assert.assertEquals(mockCId1, scheduler.taskAllocations.get(mockTask1).getId());
    Assert.assertEquals(mockCId2, scheduler.taskAllocations.get(mockTask3).getId());
    Assert.assertEquals(mockCId3A, scheduler.taskAllocations.get(mockTask3KillA).getId());
    // high priority container assigned to lower pri task. This task should still be preempted
    // because the task priority is relevant for preemption and not the container priority
    Assert.assertEquals(mockCId3B, scheduler.taskAllocations.get(mockTask3KillB).getId());
    // no preemption
    scheduler.getProgress();
    drainableAppCallback.drain();
    verify(mockRMClient, times(0)).releaseAssignedContainer((ContainerId) any());
    // no need for task preemption until now - so they should match
    Assert.assertEquals(scheduler.numHeartbeats, scheduler.heartbeatAtLastPreemption);
    // add a pending request that cannot be allocated until resources free up
    Object mockTask3WaitCookie = new Object();
    scheduler.allocateTask(mockTask3Wait, taskAsk, null, null, pri6, obj3, mockTask3WaitCookie);
    // add a pri 8 request for the pri 8 container that will not be matched
    Object mockTaskPri8Cookie = new Object();
    scheduler.allocateTask(mockTaskPri8, taskAsk, null, null, pri8, obj3, mockTaskPri8Cookie);
    // no preemption - same pri
    scheduler.getProgress();
    drainableAppCallback.drain();
    verify(mockRMClient, times(6)).addContainerRequest(requestCaptor.capture());
    verify(mockRMClient, times(0)).releaseAssignedContainer((ContainerId) any());
    Container mockContainer4 = mock(Container.class, RETURNS_DEEP_STUBS);
    when(mockContainer4.getNodeId().getHost()).thenReturn("host1");
    when(mockContainer4.getResource()).thenReturn(taskAsk);
    when(mockContainer4.getPriority()).thenReturn(pri8);
    ContainerId mockCId4 = mock(ContainerId.class);
    when(mockContainer4.getId()).thenReturn(mockCId4);
    containers.clear();
    containers.add(mockContainer4);
    // new lower pri container added that wont be matched and eventually preempted
    // Fudge new container being present in delayed allocation list due to race
    HeldContainer heldContainer = new HeldContainer(mockContainer4, -1, -1, null, containerSignatureMatcher);
    scheduler.delayedContainerManager.delayedContainers.add(heldContainer);
    // no preemption - container assignment attempts < 3
    scheduler.getProgress();
    drainableAppCallback.drain();
    verify(mockRMClient, times(0)).releaseAssignedContainer((ContainerId) any());
    // no need for task preemption until now - so they should match
    Assert.assertEquals(scheduler.numHeartbeats, scheduler.heartbeatAtLastPreemption);
    heldContainer.incrementAssignmentAttempts();
    // no preemption - container assignment attempts < 3
    scheduler.getProgress();
    drainableAppCallback.drain();
    verify(mockRMClient, times(0)).releaseAssignedContainer((ContainerId) any());
    heldContainer.incrementAssignmentAttempts();
    heldContainer.incrementAssignmentAttempts();
    // preemption - container released and resource asked again
    scheduler.getProgress();
    drainableAppCallback.drain();
    verify(mockRMClient, times(1)).releaseAssignedContainer((ContainerId) any());
    verify(mockRMClient, times(1)).releaseAssignedContainer(mockCId4);
    // internally re-request pri8 task request because we release pri8 new container
    verify(mockRMClient, times(7)).addContainerRequest(requestCaptor.capture());
    CookieContainerRequest reAdded = requestCaptor.getValue();
    Assert.assertEquals(pri8, reAdded.getPriority());
    Assert.assertEquals(taskAsk, reAdded.getCapability());
    Assert.assertEquals(mockTaskPri8Cookie, reAdded.getCookie().getAppCookie());
    // remove fudging.
    scheduler.delayedContainerManager.delayedContainers.clear();
    // no need for task preemption until now - so they should match
    Assert.assertEquals(scheduler.numHeartbeats, scheduler.heartbeatAtLastPreemption);
    scheduler.allocateTask(mockTask3Retry, taskAsk, null, null, pri5, obj3, null);
    // no preemption - higher pri. exact match
    scheduler.getProgress();
    // no need for task preemption until now - so they should match
    drainableAppCallback.drain();
    // no need for task preemption until now - so they should match
    Assert.assertEquals(scheduler.numHeartbeats, scheduler.heartbeatAtLastPreemption);
    verify(mockRMClient, times(1)).releaseAssignedContainer((ContainerId) any());
    for (int i = 0; i < 11; ++i) {
        scheduler.allocateTask(mockTask2, taskAsk, null, null, pri4, null, null);
    }
    drainableAppCallback.drain();
    // mockTaskPri3KillB gets preempted to clear 10% of outstanding running preemptable tasks
    // this is also a higher priority container than the pending task priority but was running a
    // lower priority task. Task priority is relevant for preemption and not container priority as
    // containers can run tasks of different priorities
    // first heartbeat
    scheduler.getProgress();
    Assert.assertTrue(scheduler.numHeartbeats > scheduler.heartbeatAtLastPreemption);
    drainableAppCallback.drain();
    // second heartbeat
    scheduler.getProgress();
    drainableAppCallback.drain();
    verify(mockRMClient, times(1)).releaseAssignedContainer((ContainerId) any());
    // third heartbeat
    scheduler.getProgress();
    drainableAppCallback.drain();
    verify(mockRMClient, times(2)).releaseAssignedContainer((ContainerId) any());
    verify(mockRMClient, times(1)).releaseAssignedContainer(mockCId3B);
    Assert.assertEquals(scheduler.numHeartbeats, scheduler.heartbeatAtLastPreemption);
    // there are pending preemptions.
    // first heartbeat
    scheduler.getProgress();
    // second heartbeat
    scheduler.getProgress();
    verify(mockRMClient, times(2)).releaseAssignedContainer((ContainerId) any());
    // third heartbeat
    scheduler.getProgress();
    drainableAppCallback.drain();
    // Next oldest mockTaskPri3KillA gets preempted to clear 10% of outstanding running preemptable tasks
    verify(mockRMClient, times(3)).releaseAssignedContainer((ContainerId) any());
    verify(mockRMClient, times(1)).releaseAssignedContainer(mockCId3A);
    AppFinalStatus finalStatus = new AppFinalStatus(FinalApplicationStatus.SUCCEEDED, "", DEFAULT_APP_URL);
    when(mockApp.getFinalAppStatus()).thenReturn(finalStatus);
    scheduler.shutdown();
    drainableAppCallback.drain();
}

Example 2 with HeldContainer

use of org.apache.tez.dag.app.rm.YarnTaskSchedulerService.HeldContainer in project tez by apache.

the class TestTaskScheduler method testTaskSchedulerDetermineMinHeldContainers.

@Test(timeout = 5000)
public void testTaskSchedulerDetermineMinHeldContainers() throws Exception {
    TezAMRMClientAsync<CookieContainerRequest> mockRMClient = spy(new AMRMClientAsyncForTest(new AMRMClientForTest(), 100));
    TaskSchedulerContext mockApp = setupMockTaskSchedulerContext(DEFAULT_APP_HOST, DEFAULT_APP_PORT, DEFAULT_APP_URL, true, new Configuration());
    final TaskSchedulerContextDrainable drainableAppCallback = createDrainableContext(mockApp);
    TaskSchedulerWithDrainableContext scheduler = new TaskSchedulerWithDrainableContext(drainableAppCallback, mockRMClient);
    scheduler.initialize();
    scheduler.start();
    String rack1 = "r1";
    String rack2 = "r2";
    String rack3 = "r3";
    String node1Rack1 = "n1r1";
    String node2Rack1 = "n2r1";
    String node1Rack2 = "n1r2";
    String node2Rack2 = "n2r2";
    String node1Rack3 = "n1r3";
    ApplicationAttemptId appId = ApplicationAttemptId.newInstance(ApplicationId.newInstance(0, 0), 0);
    Resource r = Resource.newInstance(0, 0);
    ContainerId mockCId1 = ContainerId.newInstance(appId, 0);
    Container c1 = mock(Container.class, RETURNS_DEEP_STUBS);
    // we are mocking directly
    when(c1.getNodeId().getHost()).thenReturn("");
    HeldContainer hc1 = Mockito.spy(new HeldContainer(c1, 0, 0, null, containerSignatureMatcher));
    when(hc1.getNode()).thenReturn(node1Rack1);
    when(hc1.getRack()).thenReturn(rack1);
    when(c1.getId()).thenReturn(mockCId1);
    when(c1.getResource()).thenReturn(r);
    when(hc1.getContainer()).thenReturn(c1);
    ContainerId mockCId2 = ContainerId.newInstance(appId, 1);
    Container c2 = mock(Container.class, RETURNS_DEEP_STUBS);
    // we are mocking directly
    when(c2.getNodeId().getHost()).thenReturn("");
    HeldContainer hc2 = Mockito.spy(new HeldContainer(c2, 0, 0, null, containerSignatureMatcher));
    when(hc2.getNode()).thenReturn(node2Rack1);
    when(hc2.getRack()).thenReturn(rack1);
    when(c2.getId()).thenReturn(mockCId2);
    when(c2.getResource()).thenReturn(r);
    when(hc2.getContainer()).thenReturn(c2);
    ContainerId mockCId3 = ContainerId.newInstance(appId, 2);
    Container c3 = mock(Container.class, RETURNS_DEEP_STUBS);
    // we are mocking directly
    when(c3.getNodeId().getHost()).thenReturn("");
    HeldContainer hc3 = Mockito.spy(new HeldContainer(c3, 0, 0, null, containerSignatureMatcher));
    when(hc3.getNode()).thenReturn(node1Rack1);
    when(hc3.getRack()).thenReturn(rack1);
    when(c3.getId()).thenReturn(mockCId3);
    when(c3.getResource()).thenReturn(r);
    when(hc3.getContainer()).thenReturn(c3);
    ContainerId mockCId4 = ContainerId.newInstance(appId, 3);
    Container c4 = mock(Container.class, RETURNS_DEEP_STUBS);
    // we are mocking directly
    when(c4.getNodeId().getHost()).thenReturn("");
    HeldContainer hc4 = Mockito.spy(new HeldContainer(c4, 0, 0, null, containerSignatureMatcher));
    when(hc4.getNode()).thenReturn(node2Rack1);
    when(hc4.getRack()).thenReturn(rack1);
    when(c4.getId()).thenReturn(mockCId4);
    when(c4.getResource()).thenReturn(r);
    when(hc4.getContainer()).thenReturn(c4);
    ContainerId mockCId5 = ContainerId.newInstance(appId, 4);
    Container c5 = mock(Container.class, RETURNS_DEEP_STUBS);
    // we are mocking directly
    when(c5.getNodeId().getHost()).thenReturn("");
    HeldContainer hc5 = Mockito.spy(new HeldContainer(c5, 0, 0, null, containerSignatureMatcher));
    when(hc5.getNode()).thenReturn(node1Rack2);
    when(hc5.getRack()).thenReturn(rack2);
    when(c5.getId()).thenReturn(mockCId5);
    when(c5.getResource()).thenReturn(r);
    when(hc5.getContainer()).thenReturn(c5);
    ContainerId mockCId6 = ContainerId.newInstance(appId, 5);
    Container c6 = mock(Container.class, RETURNS_DEEP_STUBS);
    // we are mocking directly
    when(c6.getNodeId().getHost()).thenReturn("");
    HeldContainer hc6 = Mockito.spy(new HeldContainer(c6, 0, 0, null, containerSignatureMatcher));
    when(hc6.getNode()).thenReturn(node2Rack2);
    when(hc6.getRack()).thenReturn(rack2);
    when(c6.getId()).thenReturn(mockCId6);
    when(c6.getResource()).thenReturn(r);
    when(hc6.getContainer()).thenReturn(c6);
    ContainerId mockCId7 = ContainerId.newInstance(appId, 6);
    Container c7 = mock(Container.class, RETURNS_DEEP_STUBS);
    // we are mocking directly
    when(c7.getNodeId().getHost()).thenReturn("");
    HeldContainer hc7 = Mockito.spy(new HeldContainer(c7, 0, 0, null, containerSignatureMatcher));
    when(hc7.getNode()).thenReturn(node1Rack3);
    when(hc7.getRack()).thenReturn(rack3);
    when(c7.getId()).thenReturn(mockCId7);
    when(c7.getResource()).thenReturn(r);
    when(hc7.getContainer()).thenReturn(c7);
    scheduler.heldContainers.put(mockCId1, hc1);
    scheduler.heldContainers.put(mockCId2, hc2);
    scheduler.heldContainers.put(mockCId3, hc3);
    scheduler.heldContainers.put(mockCId4, hc4);
    scheduler.heldContainers.put(mockCId5, hc5);
    scheduler.heldContainers.put(mockCId6, hc6);
    scheduler.heldContainers.put(mockCId7, hc7);
    // test empty case
    scheduler.sessionNumMinHeldContainers = 0;
    scheduler.determineMinHeldContainers();
    Assert.assertEquals(0, scheduler.sessionMinHeldContainers.size());
    // test min >= held
    scheduler.sessionNumMinHeldContainers = 7;
    scheduler.determineMinHeldContainers();
    Assert.assertEquals(7, scheduler.sessionMinHeldContainers.size());
    // test min < held
    scheduler.sessionNumMinHeldContainers = 5;
    scheduler.determineMinHeldContainers();
    Assert.assertEquals(5, scheduler.sessionMinHeldContainers.size());
    Set<HeldContainer> heldContainers = Sets.newHashSet();
    for (ContainerId cId : scheduler.sessionMinHeldContainers) {
        heldContainers.add(scheduler.heldContainers.get(cId));
    }
    Set<String> racks = Sets.newHashSet();
    Set<String> nodes = Sets.newHashSet();
    for (HeldContainer hc : heldContainers) {
        nodes.add(hc.getNode());
        racks.add(hc.getRack());
    }
    // 1 container from each node in rack1 and rack2. 1 container from rack3.
    // covers not enough containers in rack (rack 3)
    // covers just enough containers in rack (rack 2)
    // covers more than enough containers in rack (rack 1)
    Assert.assertEquals(5, nodes.size());
    Assert.assertTrue(nodes.contains(node1Rack1) && nodes.contains(node2Rack1) && nodes.contains(node1Rack2) && nodes.contains(node2Rack2) && nodes.contains(node1Rack3));
    Assert.assertEquals(3, racks.size());
    Assert.assertTrue(racks.contains(rack1) && racks.contains(rack2) && racks.contains(rack3));
    long currTime = System.currentTimeMillis();
    heldContainers.clear();
    heldContainers.addAll(scheduler.heldContainers.values());
    for (HeldContainer hc : heldContainers) {
        when(hc.isNew()).thenReturn(true);
        scheduler.delayedContainerManager.addDelayedContainer(hc.getContainer(), currTime);
    }
    Thread.sleep(1000);
    drainableAppCallback.drain();
    // only the 2 container not in min-held containers are released
    verify(mockRMClient, times(2)).releaseAssignedContainer((ContainerId) any());
    Assert.assertEquals(5, scheduler.heldContainers.size());
    AppFinalStatus finalStatus = new AppFinalStatus(FinalApplicationStatus.SUCCEEDED, SUCCEED_APP_MESSAGE, DEFAULT_APP_URL);
    when(mockApp.getFinalAppStatus()).thenReturn(finalStatus);
    scheduler.shutdown();
}

Example 3 with HeldContainer

use of org.apache.tez.dag.app.rm.YarnTaskSchedulerService.HeldContainer in project tez by apache.

the class TestTaskScheduler method testTaskSchedulerHeldContainersReleaseAfterExpired.

@Test(timeout = 3000)
public void testTaskSchedulerHeldContainersReleaseAfterExpired() throws Exception {
    final TezAMRMClientAsync<CookieContainerRequest> mockRMClient = spy(new AMRMClientAsyncForTest(new AMRMClientForTest(), 100));
    final TaskSchedulerContext mockApp = setupMockTaskSchedulerContext(DEFAULT_APP_HOST, DEFAULT_APP_PORT, DEFAULT_APP_URL, true, new Configuration());
    final TaskSchedulerContextDrainable drainableAppCallback = createDrainableContext(mockApp);
    final TaskSchedulerWithDrainableContext scheduler = new TaskSchedulerWithDrainableContext(drainableAppCallback, mockRMClient);
    scheduler.initialize();
    scheduler.start();
    ApplicationAttemptId appId = ApplicationAttemptId.newInstance(ApplicationId.newInstance(0, 0), 0);
    ContainerId containerId = ContainerId.newInstance(appId, 0);
    Container c1 = mock(Container.class, RETURNS_DEEP_STUBS);
    // we are mocking directly
    when(c1.getNodeId().getHost()).thenReturn("");
    HeldContainer hc1 = mock(HeldContainer.class);
    when(c1.getId()).thenReturn(containerId);
    when(hc1.getContainer()).thenReturn(c1);
    when(hc1.isNew()).thenReturn(false);
    // containerExpiryTime = 0
    scheduler.heldContainers.put(containerId, hc1);
    long currTime = System.currentTimeMillis();
    scheduler.delayedContainerManager.addDelayedContainer(hc1.getContainer(), currTime);
    // sleep and wait for mainLoop() check-in to release this expired held container.
    Thread.sleep(1000);
    verify(mockRMClient, times(1)).releaseAssignedContainer((ContainerId) any());
    Assert.assertEquals(0, scheduler.heldContainers.size());
    AppFinalStatus finalStatus = new AppFinalStatus(FinalApplicationStatus.SUCCEEDED, SUCCEED_APP_MESSAGE, DEFAULT_APP_URL);
    when(mockApp.getFinalAppStatus()).thenReturn(finalStatus);
    scheduler.shutdown();
}