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Add PersistentTasksClusterService::unassignPersistentTask method #37576

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merged 6 commits into from
Jan 23, 2019
Merged

Add PersistentTasksClusterService::unassignPersistentTask method #37576

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6340be8
Add PersistentTasksClusterService::unassignPersistentTask method
benwtrent Jan 17, 2019
11af7df
adding cancellation test
benwtrent Jan 17, 2019
5cd2f9d
Adding integration test for unallocating tasks from a node
benwtrent Jan 18, 2019
df24e18
Addressing review comments
benwtrent Jan 22, 2019
5fcf03a
Merge branch 'master' into feature/adding-unassign-task-method
benwtrent Jan 23, 2019
7756bc7
adressing minor PR comments
benwtrent Jan 23, 2019
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45 changes: 44 additions & 1 deletion server/src/main/java/org/elasticsearch/persistent/PersistentTasksClusterService.java
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Original file line number Diff line number Diff line change
Expand Up @@ -247,6 +247,45 @@ public void clusterStateProcessed(String source, ClusterState oldState, ClusterS
});
}

/**
* This unassigns a task from any node, i.e. it is assigned to a {@code null} node with the provided reason.
*
* Since the assignment executor node is null, the {@link PersistentTasksClusterService} will attempt to reassign it to a valid
* node quickly.
*
* @param taskId the id of a persistent task
* @param taskAllocationId the expected allocation id of the persistent task
* @param reason the reason for unassigning the task from any node
* @param listener the listener that will be called when task is unassigned
*/
public void unassignPersistentTask(final String taskId,
final long taskAllocationId,
final String reason,
final ActionListener<PersistentTask<?>> listener) {
clusterService.submitStateUpdateTask("unassign persistent task from any node", new ClusterStateUpdateTask() {
@Override
public ClusterState execute(ClusterState currentState) throws Exception {
PersistentTasksCustomMetaData.Builder tasksInProgress = builder(currentState);
if (tasksInProgress.hasTask(taskId, taskAllocationId)) {
logger.trace("Unassigning task {} with allocation id {}", taskId, taskAllocationId);
return update(currentState, tasksInProgress.reassignTask(taskId, unassignedAssignment(reason)));
} else {
throw new ResourceNotFoundException("the task with id {} and allocation id {} doesn't exist", taskId, taskAllocationId);
}
}

@Override
public void onFailure(String source, Exception e) {
listener.onFailure(e);
}

@Override
public void clusterStateProcessed(String source, ClusterState oldState, ClusterState newState) {
listener.onResponse(PersistentTasksCustomMetaData.getTaskWithId(newState, taskId));
}
});
}

/**
* Creates a new {@link Assignment} for the given persistent task.
*
Expand All @@ -263,7 +302,7 @@ private <Params extends PersistentTaskParams> Assignment createAssignment(final

AssignmentDecision decision = decider.canAssign();
if (decision.getType() == AssignmentDecision.Type.NO) {
return new Assignment(null, "persistent task [" + taskName + "] cannot be assigned [" + decision.getReason() + "]");
return unassignedAssignment("persistent task [" + taskName + "] cannot be assigned [" + decision.getReason() + "]");
}

return persistentTasksExecutor.getAssignment(taskParams, currentState);
Expand Down Expand Up @@ -404,6 +443,10 @@ private static ClusterState update(ClusterState currentState, PersistentTasksCus
}
}

private static Assignment unassignedAssignment(String reason) {
return new Assignment(null, reason);
}

/**
* Class to periodically try to reassign unassigned persistent tasks.
*/
Expand Down
61 changes: 59 additions & 2 deletions server/src/test/java/org/elasticsearch/persistent/PersistentTasksClusterServiceTests.java
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Original file line number Diff line number Diff line change
Expand Up @@ -20,7 +20,9 @@
package org.elasticsearch.persistent;

import com.carrotsearch.hppc.cursors.ObjectCursor;
import org.elasticsearch.ResourceNotFoundException;
import org.elasticsearch.Version;
import org.elasticsearch.action.ActionListener;
import org.elasticsearch.cluster.ClusterChangedEvent;
import org.elasticsearch.cluster.ClusterName;
import org.elasticsearch.cluster.ClusterState;
Expand Down Expand Up @@ -63,10 +65,13 @@
import static org.elasticsearch.persistent.PersistentTasksClusterService.persistentTasksChanged;
import static org.elasticsearch.persistent.PersistentTasksExecutor.NO_NODE_FOUND;
import static org.elasticsearch.test.ClusterServiceUtils.createClusterService;
import static org.elasticsearch.test.ClusterServiceUtils.setState;
import static org.hamcrest.Matchers.equalTo;
import static org.hamcrest.Matchers.instanceOf;
import static org.hamcrest.Matchers.lessThanOrEqualTo;
import static org.hamcrest.Matchers.notNullValue;
import static org.hamcrest.Matchers.nullValue;
import static org.hamcrest.core.Is.is;
import static org.mockito.Matchers.any;
import static org.mockito.Matchers.anyString;
import static org.mockito.Mockito.doAnswer;
Expand Down Expand Up @@ -464,6 +469,56 @@ public void testPeriodicRecheck() throws Exception {
});
}

public void testUnassignTask() {
ClusterState clusterState = initialState();
ClusterState.Builder builder = ClusterState.builder(clusterState);
PersistentTasksCustomMetaData.Builder tasks = PersistentTasksCustomMetaData.builder(
clusterState.metaData().custom(PersistentTasksCustomMetaData.TYPE));
DiscoveryNodes.Builder nodes = DiscoveryNodes.builder()
.add(new DiscoveryNode("_node_1", buildNewFakeTransportAddress(), Version.CURRENT))
.localNodeId("_node_1")
.masterNodeId("_node_1")
.add(new DiscoveryNode("_node_2", buildNewFakeTransportAddress(), Version.CURRENT));

String unassignedId = addTask(tasks, "unassign", "_node_2");

MetaData.Builder metaData = MetaData.builder(clusterState.metaData()).putCustom(PersistentTasksCustomMetaData.TYPE, tasks.build());
clusterState = builder.metaData(metaData).nodes(nodes).build();
setState(clusterService, clusterState);
PersistentTasksClusterService service = createService((params, currentState) ->
new Assignment("_node_2", "test"));
service.unassignPersistentTask(unassignedId, tasks.getLastAllocationId(), "unassignment test", ActionListener.wrap(
task -> {
assertThat(task.getAssignment().getExecutorNode(), is(nullValue()));
assertThat(task.getId(), equalTo(unassignedId));
assertThat(task.getAssignment().getExplanation(), equalTo("unassignment test"));
},
e -> fail()
));
}

public void testUnassignNonExistentTask() {
ClusterState clusterState = initialState();
ClusterState.Builder builder = ClusterState.builder(clusterState);
PersistentTasksCustomMetaData.Builder tasks = PersistentTasksCustomMetaData.builder(
clusterState.metaData().custom(PersistentTasksCustomMetaData.TYPE));
DiscoveryNodes.Builder nodes = DiscoveryNodes.builder()
.add(new DiscoveryNode("_node_1", buildNewFakeTransportAddress(), Version.CURRENT))
.localNodeId("_node_1")
.masterNodeId("_node_1")
.add(new DiscoveryNode("_node_2", buildNewFakeTransportAddress(), Version.CURRENT));

MetaData.Builder metaData = MetaData.builder(clusterState.metaData()).putCustom(PersistentTasksCustomMetaData.TYPE, tasks.build());
clusterState = builder.metaData(metaData).nodes(nodes).build();
setState(clusterService, clusterState);
PersistentTasksClusterService service = createService((params, currentState) ->
new Assignment("_node_2", "test"));
service.unassignPersistentTask("missing-task", tasks.getLastAllocationId(), "unassignment test", ActionListener.wrap(
task -> fail(),
e -> assertThat(e, instanceOf(ResourceNotFoundException.class))
));
}

private ClusterService createRecheckTestClusterService(ClusterState initialState, boolean shouldSimulateFailure) {
AtomicBoolean testFailureNextTime = new AtomicBoolean(shouldSimulateFailure);
AtomicReference<ClusterState> state = new AtomicReference<>(initialState);
Expand Down Expand Up @@ -728,9 +783,11 @@ private ClusterState.Builder addRandomTask(ClusterState.Builder clusterStateBuil
tasks.addTask(UUIDs.base64UUID(), TestPersistentTasksExecutor.NAME, new TestParams(param), assignment).build()));
}

private void addTask(PersistentTasksCustomMetaData.Builder tasks, String param, String node) {
tasks.addTask(UUIDs.base64UUID(), TestPersistentTasksExecutor.NAME, new TestParams(param),
private String addTask(PersistentTasksCustomMetaData.Builder tasks, String param, String node) {
String id = UUIDs.base64UUID();
tasks.addTask(id, TestPersistentTasksExecutor.NAME, new TestParams(param),
new Assignment(node, "explanation: " + param));
return id;
}

private DiscoveryNode newNode(String nodeId) {
Expand Down
97 changes: 81 additions & 16 deletions server/src/test/java/org/elasticsearch/persistent/PersistentTasksExecutorIT.java
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Original file line number Diff line number Diff line change
Expand Up @@ -46,8 +46,10 @@
import static org.elasticsearch.test.hamcrest.ElasticsearchAssertions.assertThrows;
import static org.hamcrest.Matchers.empty;
import static org.hamcrest.Matchers.equalTo;
import static org.hamcrest.Matchers.hasSize;
import static org.hamcrest.Matchers.notNullValue;
import static org.hamcrest.Matchers.nullValue;
import static org.hamcrest.core.Is.is;

@ESIntegTestCase.ClusterScope(scope = ESIntegTestCase.Scope.SUITE, minNumDataNodes = 2)
public class PersistentTasksExecutorIT extends ESIntegTestCase {
Expand Down Expand Up @@ -155,11 +157,8 @@ public void testPersistentActionWithNoAvailableNode() throws Exception {
Settings nodeSettings = Settings.builder().put(nodeSettings(0)).put("node.attr.test_attr", "test").build();
String newNode = internalCluster().startNode(nodeSettings);
String newNodeId = internalCluster().clusterService(newNode).localNode().getId();
assertBusy(() -> {
// Wait for the task to start
assertThat(client().admin().cluster().prepareListTasks().setActions(TestPersistentTasksExecutor.NAME + "[c]").get().getTasks()
.size(), equalTo(1));
});
waitForTaskToStart();

TaskInfo taskInfo = client().admin().cluster().prepareListTasks().setActions(TestPersistentTasksExecutor.NAME + "[c]")
.get().getTasks().get(0);

Expand Down Expand Up @@ -199,11 +198,7 @@ public void testPersistentActionWithNonClusterStateCondition() throws Exception

TestPersistentTasksExecutor.setNonClusterStateCondition(true);

assertBusy(() -> {
// Wait for the task to start
assertThat(client().admin().cluster().prepareListTasks().setActions(TestPersistentTasksExecutor.NAME + "[c]").get().getTasks()
.size(), equalTo(1));
});
waitForTaskToStart();
TaskInfo taskInfo = client().admin().cluster().prepareListTasks().setActions(TestPersistentTasksExecutor.NAME + "[c]")
.get().getTasks().get(0);

Expand All @@ -221,12 +216,7 @@ public void testPersistentActionStatusUpdate() throws Exception {
PlainActionFuture<PersistentTask<TestParams>> future = new PlainActionFuture<>();
persistentTasksService.sendStartRequest(UUIDs.base64UUID(), TestPersistentTasksExecutor.NAME, new TestParams("Blah"), future);
String taskId = future.get().getId();

assertBusy(() -> {
// Wait for the task to start
assertThat(client().admin().cluster().prepareListTasks().setActions(TestPersistentTasksExecutor.NAME + "[c]").get().getTasks()
.size(), equalTo(1));
});
waitForTaskToStart();
TaskInfo firstRunningTask = client().admin().cluster().prepareListTasks().setActions(TestPersistentTasksExecutor.NAME + "[c]")
.get().getTasks().get(0);

Expand Down Expand Up @@ -307,6 +297,62 @@ public void testCreatePersistentTaskWithDuplicateId() throws Exception {
});
}

public void testUnassignRunningPersistentTask() throws Exception {
PersistentTasksClusterService persistentTasksClusterService =
internalCluster().getInstance(PersistentTasksClusterService.class, internalCluster().getMasterName());
// Speed up rechecks to a rate that is quicker than what settings would allow
persistentTasksClusterService.setRecheckInterval(TimeValue.timeValueMillis(1));
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Is there a risk to set it to a such low value?

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There is already another test that sets 1ms for the recheck interval. I agree 1ms would be a completely inappropriate setting for production, but that's why it's being set via a method that end users cannot call. I think if a test fails because the interval is low then it will be exposing a bug that could happen with a higher setting, just much less frequently. During this test it's true that the master node will be doing a lot of work iterating through the persistent tasks list, but it won't be doing the other work that a production master node would be doing, so a modern CPU should be able to cope.

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Thanks for the precision. I just wanted to be sure that this value couldn't overhelm any thread pool and cause other issues.

PersistentTasksService persistentTasksService = internalCluster().getInstance(PersistentTasksService.class);
PlainActionFuture<PersistentTask<TestParams>> future = new PlainActionFuture<>();
TestParams testParams = new TestParams("Blah");
testParams.setExecutorNodeAttr("test");
persistentTasksService.sendStartRequest(UUIDs.base64UUID(), TestPersistentTasksExecutor.NAME, testParams, future);
PersistentTask<TestParams> task = future.get();
String taskId = task.getId();

Settings nodeSettings = Settings.builder().put(nodeSettings(0)).put("node.attr.test_attr", "test").build();
internalCluster().startNode(nodeSettings);

waitForTaskToStart();

PlainActionFuture<PersistentTask<?>> unassignmentFuture = new PlainActionFuture<>();

// Disallow re-assignment after it is unallocated to verify master and node state
TestPersistentTasksExecutor.setNonClusterStateCondition(false);

persistentTasksClusterService.unassignPersistentTask(taskId,
task.getAllocationId() + 1,
"unassignment test",
unassignmentFuture);
PersistentTask<?> unassignedTask = unassignmentFuture.get();
assertThat(unassignedTask.getId(), equalTo(taskId));
assertThat(unassignedTask.getAssignment().getExplanation(), equalTo("unassignment test"));
assertThat(unassignedTask.getAssignment().getExecutorNode(), is(nullValue()));

assertBusy(() -> {
// Verify that the task is NOT running on the node
List<TaskInfo> tasks = client().admin().cluster().prepareListTasks().setActions(TestPersistentTasksExecutor.NAME + "[c]").get()
.getTasks();
assertThat(tasks.size(), equalTo(0));

// Verify that the task is STILL in internal cluster state
assertClusterStateHasTask(taskId);
});

// Allow it to be reassigned again to the same node
TestPersistentTasksExecutor.setNonClusterStateCondition(true);

// Verify it starts again
waitForTaskToStart();

assertClusterStateHasTask(taskId);

// Complete or cancel the running task
TaskInfo taskInfo = client().admin().cluster().prepareListTasks().setActions(TestPersistentTasksExecutor.NAME + "[c]")
.get().getTasks().get(0);
stopOrCancelTask(taskInfo.getTaskId());
}

private void stopOrCancelTask(TaskId taskId) {
if (randomBoolean()) {
logger.info("Completing the running task");
Expand All @@ -322,6 +368,25 @@ private void stopOrCancelTask(TaskId taskId) {
}
}

private static void waitForTaskToStart() throws Exception {
assertBusy(() -> {
// Wait for the task to start
assertThat(client().admin().cluster().prepareListTasks().setActions(TestPersistentTasksExecutor.NAME + "[c]").get().getTasks()
.size(), equalTo(1));
});
}

private static void assertClusterStateHasTask(String taskId) {
Collection<PersistentTask<?>> clusterTasks = ((PersistentTasksCustomMetaData) internalCluster()
.clusterService()
.state()
.getMetaData()
.custom(PersistentTasksCustomMetaData.TYPE))
.tasks();
assertThat(clusterTasks, hasSize(1));
assertThat(clusterTasks.iterator().next().getId(), equalTo(taskId));
}

private void assertNoRunningTasks() throws Exception {
assertBusy(() -> {
// Wait for the task to finish
Expand Down