org.elasticsearch.persistent.PersistentTasksClusterService Maven / Gradle / Ivy
Go to download
Show more of this group Show more artifacts with this name
Show all versions of elasticsearch Show documentation
Show all versions of elasticsearch Show documentation
Elasticsearch subproject :server
/*
* Licensed to Elasticsearch under one or more contributor
* license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright
* ownership. Elasticsearch 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.elasticsearch.persistent;
import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;
import org.elasticsearch.ResourceAlreadyExistsException;
import org.elasticsearch.ResourceNotFoundException;
import org.elasticsearch.action.ActionListener;
import org.elasticsearch.cluster.ClusterChangedEvent;
import org.elasticsearch.cluster.ClusterState;
import org.elasticsearch.cluster.ClusterStateListener;
import org.elasticsearch.cluster.ClusterStateUpdateTask;
import org.elasticsearch.cluster.metadata.MetaData;
import org.elasticsearch.cluster.node.DiscoveryNodes;
import org.elasticsearch.cluster.service.ClusterService;
import org.elasticsearch.common.settings.Setting;
import org.elasticsearch.common.settings.Settings;
import org.elasticsearch.common.unit.TimeValue;
import org.elasticsearch.common.util.concurrent.AbstractAsyncTask;
import org.elasticsearch.persistent.PersistentTasksCustomMetaData.Assignment;
import org.elasticsearch.persistent.PersistentTasksCustomMetaData.PersistentTask;
import org.elasticsearch.persistent.decider.AssignmentDecision;
import org.elasticsearch.persistent.decider.EnableAssignmentDecider;
import org.elasticsearch.threadpool.ThreadPool;
import java.io.Closeable;
import java.util.Objects;
/**
* Component that runs only on the master node and is responsible for assigning running tasks to nodes
*/
public class PersistentTasksClusterService implements ClusterStateListener, Closeable {
public static final Setting CLUSTER_TASKS_ALLOCATION_RECHECK_INTERVAL_SETTING =
Setting.timeSetting("cluster.persistent_tasks.allocation.recheck_interval", TimeValue.timeValueSeconds(30),
TimeValue.timeValueSeconds(10), Setting.Property.Dynamic, Setting.Property.NodeScope);
private static final Logger logger = LogManager.getLogger(PersistentTasksClusterService.class);
private final ClusterService clusterService;
private final PersistentTasksExecutorRegistry registry;
private final EnableAssignmentDecider decider;
private final ThreadPool threadPool;
private final PeriodicRechecker periodicRechecker;
public PersistentTasksClusterService(Settings settings, PersistentTasksExecutorRegistry registry, ClusterService clusterService,
ThreadPool threadPool) {
this.clusterService = clusterService;
this.registry = registry;
this.decider = new EnableAssignmentDecider(settings, clusterService.getClusterSettings());
this.threadPool = threadPool;
this.periodicRechecker = new PeriodicRechecker(CLUSTER_TASKS_ALLOCATION_RECHECK_INTERVAL_SETTING.get(settings));
clusterService.addListener(this);
clusterService.getClusterSettings().addSettingsUpdateConsumer(CLUSTER_TASKS_ALLOCATION_RECHECK_INTERVAL_SETTING,
this::setRecheckInterval);
}
// visible for testing only
public void setRecheckInterval(TimeValue recheckInterval) {
periodicRechecker.setInterval(recheckInterval);
}
@Override
public void close() {
periodicRechecker.close();
}
/**
* Creates a new persistent task on master node
*
* @param taskId the task's id
* @param taskName the task's name
* @param taskParams the task's parameters
* @param listener the listener that will be called when task is started
*/
public void createPersistentTask(String taskId, String taskName, Params taskParams,
ActionListener> listener) {
clusterService.submitStateUpdateTask("create persistent task", new ClusterStateUpdateTask() {
@Override
public ClusterState execute(ClusterState currentState) {
PersistentTasksCustomMetaData.Builder builder = builder(currentState);
if (builder.hasTask(taskId)) {
throw new ResourceAlreadyExistsException("task with id {" + taskId + "} already exist");
}
PersistentTasksExecutor taskExecutor = registry.getPersistentTaskExecutorSafe(taskName);
taskExecutor.validate(taskParams, currentState);
Assignment assignment = createAssignment(taskName, taskParams, currentState);
return update(currentState, builder.addTask(taskId, taskName, taskParams, assignment));
}
@Override
public void onFailure(String source, Exception e) {
listener.onFailure(e);
}
@SuppressWarnings("unchecked")
@Override
public void clusterStateProcessed(String source, ClusterState oldState, ClusterState newState) {
PersistentTasksCustomMetaData tasks = newState.getMetaData().custom(PersistentTasksCustomMetaData.TYPE);
if (tasks != null) {
PersistentTask task = tasks.getTask(taskId);
listener.onResponse(task);
if (task != null && task.isAssigned() == false && periodicRechecker.isScheduled() == false) {
periodicRechecker.rescheduleIfNecessary();
}
} else {
listener.onResponse(null);
}
}
});
}
/**
* Restarts a record about a running persistent task from cluster state
*
* @param id the id of the persistent task
* @param allocationId the allocation id of the persistent task
* @param failure the reason for restarting the task or null if the task completed successfully
* @param listener the listener that will be called when task is removed
*/
public void completePersistentTask(String id, long allocationId, Exception failure, ActionListener> listener) {
final String source;
if (failure != null) {
logger.warn("persistent task " + id + " failed", failure);
source = "finish persistent task (failed)";
} else {
source = "finish persistent task (success)";
}
clusterService.submitStateUpdateTask(source, new ClusterStateUpdateTask() {
@Override
public ClusterState execute(ClusterState currentState) {
PersistentTasksCustomMetaData.Builder tasksInProgress = builder(currentState);
if (tasksInProgress.hasTask(id, allocationId)) {
tasksInProgress.removeTask(id);
return update(currentState, tasksInProgress);
} else {
if (tasksInProgress.hasTask(id)) {
logger.warn("The task [{}] with id [{}] was found but it has a different allocation id [{}], status is not updated",
PersistentTasksCustomMetaData.getTaskWithId(currentState, id).getTaskName(), id, allocationId);
} else {
logger.warn("The task [{}] wasn't found, status is not updated", id);
}
throw new ResourceNotFoundException("the task with id [" + id + "] and allocation id [" + allocationId + "] not found");
}
}
@Override
public void onFailure(String source, Exception e) {
listener.onFailure(e);
}
@Override
public void clusterStateProcessed(String source, ClusterState oldState, ClusterState newState) {
// Using old state since in the new state the task is already gone
listener.onResponse(PersistentTasksCustomMetaData.getTaskWithId(oldState, id));
}
});
}
/**
* Removes the persistent task
*
* @param id the id of a persistent task
* @param listener the listener that will be called when task is removed
*/
public void removePersistentTask(String id, ActionListener> listener) {
clusterService.submitStateUpdateTask("remove persistent task", new ClusterStateUpdateTask() {
@Override
public ClusterState execute(ClusterState currentState) {
PersistentTasksCustomMetaData.Builder tasksInProgress = builder(currentState);
if (tasksInProgress.hasTask(id)) {
return update(currentState, tasksInProgress.removeTask(id));
} else {
throw new ResourceNotFoundException("the task with id {} doesn't exist", id);
}
}
@Override
public void onFailure(String source, Exception e) {
listener.onFailure(e);
}
@Override
public void clusterStateProcessed(String source, ClusterState oldState, ClusterState newState) {
// Using old state since in the new state the task is already gone
listener.onResponse(PersistentTasksCustomMetaData.getTaskWithId(oldState, id));
}
});
}
/**
* Update the state of a persistent task
*
* @param taskId the id of a persistent task
* @param taskAllocationId the expected allocation id of the persistent task
* @param taskState new state
* @param listener the listener that will be called when task is removed
*/
public void updatePersistentTaskState(final String taskId,
final long taskAllocationId,
final PersistentTaskState taskState,
final ActionListener> listener) {
clusterService.submitStateUpdateTask("update task state", new ClusterStateUpdateTask() {
@Override
public ClusterState execute(ClusterState currentState) {
PersistentTasksCustomMetaData.Builder tasksInProgress = builder(currentState);
if (tasksInProgress.hasTask(taskId, taskAllocationId)) {
return update(currentState, tasksInProgress.updateTaskState(taskId, taskState));
} else {
if (tasksInProgress.hasTask(taskId)) {
logger.warn("trying to update state on task {} with unexpected allocation id {}", taskId, taskAllocationId);
} else {
logger.warn("trying to update state on non-existing task {}", taskId);
}
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.
*
* @param taskName the task's name
* @param taskParams the task's parameters
* @param currentState the current {@link ClusterState}
* @return a new {@link Assignment}
*/
private Assignment createAssignment(final String taskName,
final Params taskParams,
final ClusterState currentState) {
PersistentTasksExecutor persistentTasksExecutor = registry.getPersistentTaskExecutorSafe(taskName);
AssignmentDecision decision = decider.canAssign();
if (decision.getType() == AssignmentDecision.Type.NO) {
return new Assignment(null, "persistent task [" + taskName + "] cannot be assigned [" + decision.getReason() + "]");
}
return persistentTasksExecutor.getAssignment(taskParams, currentState);
}
@Override
public void clusterChanged(ClusterChangedEvent event) {
if (event.localNodeMaster()) {
if (shouldReassignPersistentTasks(event)) {
// We want to avoid a periodic check duplicating this work
periodicRechecker.cancel();
logger.trace("checking task reassignment for cluster state {}", event.state().getVersion());
reassignPersistentTasks();
}
}
}
/**
* Submit a cluster state update to reassign any persistent tasks that need reassigning
*/
private void reassignPersistentTasks() {
clusterService.submitStateUpdateTask("reassign persistent tasks", new ClusterStateUpdateTask() {
@Override
public ClusterState execute(ClusterState currentState) {
return reassignTasks(currentState);
}
@Override
public void onFailure(String source, Exception e) {
logger.warn("failed to reassign persistent tasks", e);
// There must be a task that's worth rechecking because there was one
// that caused this method to be called and the method failed to assign it
periodicRechecker.rescheduleIfNecessary();
}
@Override
public void clusterStateProcessed(String source, ClusterState oldState, ClusterState newState) {
if (isAnyTaskUnassigned(newState.getMetaData().custom(PersistentTasksCustomMetaData.TYPE))) {
periodicRechecker.rescheduleIfNecessary();
}
}
});
}
/**
* Returns true if the cluster state change(s) require to reassign some persistent tasks. It can happen in the following
* situations: a node left or is added, the routing table changed, the master node changed, the metadata changed or the
* persistent tasks changed.
*/
boolean shouldReassignPersistentTasks(final ClusterChangedEvent event) {
final PersistentTasksCustomMetaData tasks = event.state().getMetaData().custom(PersistentTasksCustomMetaData.TYPE);
if (tasks == null) {
return false;
}
boolean masterChanged = event.previousState().nodes().isLocalNodeElectedMaster() == false;
if (persistentTasksChanged(event)
|| event.nodesChanged()
|| event.routingTableChanged()
|| event.metaDataChanged()
|| masterChanged) {
for (PersistentTask task : tasks.tasks()) {
if (needsReassignment(task.getAssignment(), event.state().nodes())) {
Assignment assignment = createAssignment(task.getTaskName(), task.getParams(), event.state());
if (Objects.equals(assignment, task.getAssignment()) == false) {
return true;
}
}
}
}
return false;
}
/**
* Returns true if any persistent task is unassigned.
*/
private boolean isAnyTaskUnassigned(final PersistentTasksCustomMetaData tasks) {
return tasks != null && tasks.tasks().stream().anyMatch(task -> task.getAssignment().isAssigned() == false);
}
/**
* Evaluates the cluster state and tries to assign tasks to nodes.
*
* @param currentState the cluster state to analyze
* @return an updated version of the cluster state
*/
ClusterState reassignTasks(final ClusterState currentState) {
ClusterState clusterState = currentState;
final PersistentTasksCustomMetaData tasks = currentState.getMetaData().custom(PersistentTasksCustomMetaData.TYPE);
if (tasks != null) {
logger.trace("reassigning {} persistent tasks", tasks.tasks().size());
final DiscoveryNodes nodes = currentState.nodes();
// We need to check if removed nodes were running any of the tasks and reassign them
for (PersistentTask task : tasks.tasks()) {
if (needsReassignment(task.getAssignment(), nodes)) {
Assignment assignment = createAssignment(task.getTaskName(), task.getParams(), clusterState);
if (Objects.equals(assignment, task.getAssignment()) == false) {
logger.trace("reassigning task {} from node {} to node {}", task.getId(),
task.getAssignment().getExecutorNode(), assignment.getExecutorNode());
clusterState = update(clusterState, builder(clusterState).reassignTask(task.getId(), assignment));
} else {
logger.trace("ignoring task {} because assignment is the same {}", task.getId(), assignment);
}
} else {
logger.trace("ignoring task {} because it is still running", task.getId());
}
}
}
return clusterState;
}
/** Returns true if the persistent tasks are not equal between the previous and the current cluster state **/
static boolean persistentTasksChanged(final ClusterChangedEvent event) {
String type = PersistentTasksCustomMetaData.TYPE;
return Objects.equals(event.state().metaData().custom(type), event.previousState().metaData().custom(type)) == false;
}
/** Returns true if the task is not assigned or is assigned to a non-existing node */
public static boolean needsReassignment(final Assignment assignment, final DiscoveryNodes nodes) {
return (assignment.isAssigned() == false || nodes.nodeExists(assignment.getExecutorNode()) == false);
}
private static PersistentTasksCustomMetaData.Builder builder(ClusterState currentState) {
return PersistentTasksCustomMetaData.builder(currentState.getMetaData().custom(PersistentTasksCustomMetaData.TYPE));
}
private static ClusterState update(ClusterState currentState, PersistentTasksCustomMetaData.Builder tasksInProgress) {
if (tasksInProgress.isChanged()) {
return ClusterState.builder(currentState).metaData(
MetaData.builder(currentState.metaData()).putCustom(PersistentTasksCustomMetaData.TYPE, tasksInProgress.build())
).build();
} else {
return currentState;
}
}
/**
* Class to periodically try to reassign unassigned persistent tasks.
*/
private class PeriodicRechecker extends AbstractAsyncTask {
PeriodicRechecker(TimeValue recheckInterval) {
super(logger, threadPool, recheckInterval, false);
}
@Override
protected boolean mustReschedule() {
return true;
}
@Override
public void runInternal() {
if (clusterService.localNode().isMasterNode()) {
final ClusterState state = clusterService.state();
logger.trace("periodic persistent task assignment check running for cluster state {}", state.getVersion());
if (isAnyTaskUnassigned(state.getMetaData().custom(PersistentTasksCustomMetaData.TYPE))) {
reassignPersistentTasks();
}
}
}
@Override
public String toString() {
return "persistent_task_recheck";
}
}
}