sequence
In this paper, we study the storm AssignmentDistributionService
AssignmentDistributionService
Storm – 2.0.0 / storm – server/SRC/main/Java/org/apache/storm/nimbus/AssignmentDistributionService Java
/**
* A service fordistributing master assignments to supervisors, this service makes the assignments notification * asynchronous. * * <p>We support multiple working threads to distribute assignment, every thread has a queue buffer. * * <p>Master will shuffle its node request to the queues,if the target queue is full, we just discard the request,
* let the supervisors sync instead.
*
* <p>Caution: this class is not thread safe.
*
* <pre>{@code
* Working mode
* +--------+ +-----------------+
* | queue1 | ==> | Working thread1 |
* +--------+ shuffle +--------+ +-----------------+
* | Master | ==>
* +--------+ +--------+ +-----------------+
* | queue2 | ==> | Working thread2 |
* +--------+ +-----------------+
* }
* </pre>
*/
public class AssignmentDistributionService implements Closeable {
//......
private ExecutorService service;
/**
* Assignments request queue.
*/
private volatile Map<Integer, LinkedBlockingQueue<NodeAssignments>> assignmentsQueue;
/**
* Add an assignments for a node/supervisor for distribution.
* @param node node id of supervisor.
* @param host host name for the node.
* @param serverPort node thrift server port.
* @param assignments the {@link org.apache.storm.generated.SupervisorAssignments}
*/
public void addAssignmentsForNode(String node, String host, Integer serverPort, SupervisorAssignments assignments) {
try {
//For some reasons, we can not get supervisor port info, eg: supervisor shutdown,
//Just skip for this scheduling round.
if (serverPort == null) {
LOG.warn("Discard an assignment distribution for node {} because server port info is missing.", node);
return;
}
boolean success = nextQueue().offer(NodeAssignments.getInstance(node, host, serverPort, assignments), 5L, TimeUnit.SECONDS);
if(! success) { LOG.warn("Discard an assignment distribution for node {} because the target sub queue is full.", node);
}
} catch (InterruptedException e) {
LOG.error("Add node assignments interrupted: {}", e.getMessage());
throw new RuntimeException(e);
}
}
private LinkedBlockingQueue<NodeAssignments> nextQueue() {
returnthis.assignmentsQueue.get(nextQueueId()); }}Copy the code- Nimbus by calling AssignmentDistributionService addAssignmentsForNode, task allocation result notification to the supervisor
- The addAssignmentsForNode container is designed to put SupervisorAssignments into assignmentsQueue
AssignmentDistributionService.getInstance
Storm – 2.0.0 / storm – server/SRC/main/Java/org/apache/storm/nimbus/AssignmentDistributionService Java
/**
* Factory method for initialize a instance.
* @param conf config.
* @return an instance of {@link AssignmentDistributionService}
*/
public static AssignmentDistributionService getInstance(Map conf) {
AssignmentDistributionService service = new AssignmentDistributionService();
service.prepare(conf);
return service;
}
/**
* Function for initialization.
*
* @param conf config
*/
public void prepare(Map conf) {
this.conf = conf;
this.random = new Random(47);
this.threadsNum = ObjectReader.getInt(conf.get(DaemonConfig.NIMBUS_ASSIGNMENTS_SERVICE_THREADS), 10);
this.queueSize = ObjectReader.getInt(conf.get(DaemonConfig.NIMBUS_ASSIGNMENTS_SERVICE_THREAD_QUEUE_SIZE), 100);
this.assignmentsQueue = new HashMap<>();
for (int i = 0; i < threadsNum; i++) {
this.assignmentsQueue.put(i, new LinkedBlockingQueue<NodeAssignments>(queueSize));
}
//start the thread pool
this.service = Executors.newFixedThreadPool(threadsNum);
this.active = true;
//start the threads
for(int i = 0; i < threadsNum; i++) { this.service.submit(new DistributeTask(this, i)); } / /for local cluster
localSupervisors = new HashMap<>();
if (ConfigUtils.isLocalMode(conf)) {
isLocalMode = true; }}Copy the code- New a AssignmentDistributionService getInstance method, at the same time prepare method to initialize
- NIMBUS_ASSIGNMENTS_SERVICE_THREAD_QUEUE_SIZE = daemonConfig. NIMBUS_ASSIGNMENTS_SERVICE_THREAD_QUEUE_SIZE = DaemonConfig
- In addition by Executors. NewFixedThreadPool (threadsNum) to create a thread pool, and then submit threadsNum DistributeTask, a DistributeTask each queue
DistributeTask
Storm – 2.0.0 / storm – server/SRC/main/Java/org/apache/storm/nimbus/AssignmentDistributionService Java
/**
* Task to distribute assignments.
*/
static class DistributeTask implements Runnable {
private AssignmentDistributionService service;
private Integer queueIndex;
DistributeTask(AssignmentDistributionService service, Integer index) {
this.service = service;
this.queueIndex = index;
}
@Override
public void run() {
while (service.isActive()) {
try {
NodeAssignments nodeAssignments = this.service.nextAssignments(queueIndex);
sendAssignmentsToNode(nodeAssignments);
} catch (InterruptedException e) {
if (service.isActive()) {
LOG.error("Get an unexpected interrupt when distributing assignments to node, {}", e.getCause());
} else {
// service is off now just interrupt it.
Thread.currentThread().interrupt();
}
}
}
}
private void sendAssignmentsToNode(NodeAssignments assignments) {
if (this.service.isLocalMode) {
//local node
Supervisor supervisor = this.service.localSupervisors.get(assignments.getNode());
if(supervisor ! = null) { supervisor.sendSupervisorAssignments(assignments.getAssignments()); }else {
LOG.error("Can not find node {} for assignments distribution", assignments.getNode());
throw new RuntimeException("null for node " + assignments.getNode() + " supervisor instance."); }}else {
// distributed mode
try (SupervisorClient client = SupervisorClient.getConfiguredClient(service.getConf(),
assignments.getHost(), assignments.getServerPort())) {
try {
client.getClient().sendSupervisorAssignments(assignments.getAssignments());
} catch (Exception e) {
//just ignore the exception.
LOG.error("Exception when trying to send assignments to node {}: {}", assignments.getNode(), e.getMessage());
}
} catch (Throwable e) {
//just ignore any error/exception.
LOG.error("Exception to create supervisor client for node {}: {}", assignments.getNode(), e.getMessage());
}
}
}
}
/**
* Get an assignments from the target queue with the specific index.
* @param queueIndex index of the queue
* @return an {@link NodeAssignments}
* @throws InterruptedException
*/
public NodeAssignments nextAssignments(Integer queueIndex) throws InterruptedException {
NodeAssignments target = null;
while (true) {
target = getQueueById(queueIndex).poll();
if(target ! = null) {returntarget; } Time.sleep(100L); }}Copy the code- AssignmentDistributionService when prepare to submit DistributeTask thread pool
- The Run method of DistributeTask repeats itself, taking NodeAssignments from the corresponding queue and calling sendAssignmentsToNode to communicate remotely
- SendAssignmentsToNode call client. GetClient (.) sendSupervisorAssignments (assignments. GetAssignments ())
Supervisor.launchSupervisorThriftServer
Storm – 2.0.0 / storm – server/SRC/main/Java/org/apache/storm/daemon/supervisor/supervisor. Java
private void launchSupervisorThriftServer(Map<String, Object> conf) throws IOException {
// validate port
int port = getThriftServerPort();
try {
ServerSocket socket = new ServerSocket(port);
socket.close();
} catch (BindException e) {
LOG.error("{} is not available. Check if another process is already listening on {}", port, port);
throw new RuntimeException(e);
}
TProcessor processor = new org.apache.storm.generated.Supervisor.Processor(
new org.apache.storm.generated.Supervisor.Iface() {
@Override
public void sendSupervisorAssignments(SupervisorAssignments assignments)
throws AuthorizationException, TException {
checkAuthorization("sendSupervisorAssignments");
LOG.info("Got an assignments from master, will start to sync with assignments: {}", assignments); SynchronizeAssignments syn = new SynchronizeAssignments(getSupervisor(), assignments, getReadClusterState()); getEventManger().add(syn); } / /... }); this.thriftServer = new ThriftServer(conf, processor, ThriftConnectionType.SUPERVISOR); this.thriftServer.serve(); }Copy the code- The Supervisor. LaunchSupervisorThriftServer, added TProcessor, add SupervisorAssignments packaging for SynchronizeAssignments to the EventManager
SynchronizeAssignments.run
Storm – 2.0.0 / storm – server/SRC/main/Java/org/apache/storm/daemon/supervisor/timer/SynchronizeAssignments. Java
/**
* A runnable which will synchronize assignments to node local and then worker processes.
*/
public class SynchronizeAssignments implements Runnable {
//......
@Override
public void run() {
// first sync assignments to local.then sync processes.
if (null == assignments) {
getAssignmentsFromMaster(this.supervisor.getConf(), this.supervisor.getStormClusterState(), this.supervisor.getAssignmentId());
} else {
assignedAssignmentsToLocal(this.supervisor.getStormClusterState(), assignments);
}
this.readClusterState.run();
}
private static void assignedAssignmentsToLocal(IStormClusterState clusterState, SupervisorAssignments assignments) {
if (null == assignments) {
//unknown error, just skip
return;
}
Map<String, byte[]> serAssignments = new HashMap<>();
for(Map.Entry<String, Assignment> entry : assignments.get_storm_assignment().entrySet()) { serAssignments.put(entry.getKey(), Utils.serialize(entry.getValue())); } clusterState.syncRemoteAssignments(serAssignments); }}Copy the code- Here call assignedAssignmentsToLocal, then also triggered the enclosing readClusterState. The run ()
- AssignedAssignmentsToLocal call clusterState. SyncRemoteAssignments (serAssignments)
StormClusterStateImpl.syncRemoteAssignments
Storm – 2.0.0 / storm/org – client/SRC/JVM/apache/storm/cluster/StormClusterStateImpl Java
@Override
public void syncRemoteAssignments(Map<String, byte[]> remote) {
if(null ! = remote) { this.assignmentsBackend.syncRemoteAssignments(remote); }else {
Map<String, byte[]> tmp = new HashMap<>();
List<String> stormIds = this.stateStorage.get_children(ClusterUtils.ASSIGNMENTS_SUBTREE, false);
for (String stormId : stormIds) {
byte[] assignment = this.stateStorage.get_data(ClusterUtils.assignmentPath(stormId), false); tmp.put(stormId, assignment); } this.assignmentsBackend.syncRemoteAssignments(tmp); }}Copy the code- Here the serAssignments information is updated to assignmentsBackend(
Local memory) - If remote is null, the allocation information is read from ZK and then updated to memory; Zk address for ClusterUtils. AssignmentPath (stormId) (
/assignments/{topologyId})
ReadClusterState.run
Storm – 2.0.0 / storm – server/SRC/main/Java/org daemon/supervisor / / apache/storm/ReadClusterState. Java
@Override
public synchronized void run() {
try {
List<String> stormIds = stormClusterState.assignments(null);
Map<String, Assignment> assignmentsSnapshot = getAssignmentsSnapshot(stormClusterState);
Map<Integer, LocalAssignment> allAssignments = readAssignments(assignmentsSnapshot);
if (allAssignments == null) {
//Something odd happened try again later
return;
}
Map<String, List<ProfileRequest>> topoIdToProfilerActions = getProfileActions(stormClusterState, stormIds);
HashSet<Integer> assignedPorts = new HashSet<>();
LOG.debug("Synchronizing supervisor");
LOG.debug("All assignment: {}", allAssignments);
LOG.debug("Topology Ids -> Profiler Actions {}", topoIdToProfilerActions);
for (Integer port : allAssignments.keySet()) {
if (iSuper.confirmAssigned(port)) {
assignedPorts.add(port);
}
}
HashSet<Integer> allPorts = new HashSet<>(assignedPorts);
iSuper.assigned(allPorts);
allPorts.addAll(slots.keySet());
Map<Integer, Set<TopoProfileAction>> filtered = new HashMap<>();
for (Entry<String, List<ProfileRequest>> entry : topoIdToProfilerActions.entrySet()) {
String topoId = entry.getKey();
if(entry.getValue() ! = null) {for (ProfileRequest req : entry.getValue()) {
NodeInfo ni = req.get_nodeInfo();
if (host.equals(ni.get_node())) {
Long port = ni.get_port().iterator().next();
Set<TopoProfileAction> actions = filtered.get(port.intValue());
if(actions == null) { actions = new HashSet<>(); filtered.put(port.intValue(), actions); } actions.add(new TopoProfileAction(topoId, req)); }}}}for (Integer port : allPorts) {
Slot slot = slots.get(port);
if (slot == null) {
slot = mkSlot(port);
slots.put(port, slot);
slot.start();
}
slot.setNewAssignment(allAssignments.get(port));
slot.addProfilerActions(filtered.get(port));
}
} catch (Exception e) {
LOG.error("Failed to Sync Supervisor", e); throw new RuntimeException(e); }}Copy the code- The slot’s AtomicReference newAssignment is set
- Slot’s run method polls the newAssignment through the stateMachineStep method and updates the nextState
summary
- Nimbus by calling AssignmentDistributionService addAssignmentsForNode, task allocation result notification to the supervisor
- The addAssignmentsForNode container is designed to put the container into assignmentsQueue. AssignmentDistributionService default to create a specified number of threads in thread pool, at the same time create a specified number of threads queue and DistributeTask
- The DistributeTask repeatedly pulls SynchronizeAssignments from the specified Queue and calls sendAssignmentsToNode to notify the Supervisor
- The Supervisor will launchSupervisorThriftServer at start-up time, registered its response sendSupervisorAssignments processor, The received container is wrapped as SynchronizeAssignments and added to the EventManager
- EventManager when handling SynchronizeAssignments perform its run method, call the assignedAssignmentsToLocal, then also triggered this. ReadClusterState. The run ()
- AssignedAssignmentsToLocal call clusterState. SyncRemoteAssignments (serAssignments) assignment information update to local memory; Readclusterstate.run () updates the slot’s newAssignment value, then relies on slot polling to sense state changes and trigger processing accordingly
doc
- Understanding the Parallelism of a Storm Topology