alluxio.master.journal.raft

Class JournalStateMachine

java.lang.Object

org.apache.ratis.statemachine.impl.BaseStateMachine

alluxio.master.journal.raft.JournalStateMachine

All Implemented Interfaces:

Closeable, AutoCloseable, org.apache.ratis.statemachine.StateMachine, org.apache.ratis.statemachine.StateMachine.DataApi, org.apache.ratis.statemachine.StateMachine.EventApi, org.apache.ratis.statemachine.StateMachine.FollowerEventApi, org.apache.ratis.statemachine.StateMachine.LeaderEventApi

@ThreadSafe
public class JournalStateMachine
extends org.apache.ratis.statemachine.impl.BaseStateMachine

A state machine for managing all of Alluxio's journaled state. Entries applied to this state machine will be forwarded to the appropriate internal master. The state machine starts by resetting all state, then applying the entries offered by Ratis. When the master becomes primary, it should wait until the state machine is up to date and no other primary master is serving, then call upgrade(). Once the state machine is upgraded, it will ignore all entries appended by Ratis because those entries are applied to primary master state before being written to Rati.

Nested Class Summary

Nested classes/interfaces inherited from class org.apache.ratis.statemachine.impl.BaseStateMachine

org.apache.ratis.statemachine.impl.BaseStateMachine.Task

Nested classes/interfaces inherited from interface org.apache.ratis.statemachine.StateMachine

org.apache.ratis.statemachine.StateMachine.DataApi, org.apache.ratis.statemachine.StateMachine.DataChannel, org.apache.ratis.statemachine.StateMachine.DataStream, org.apache.ratis.statemachine.StateMachine.EventApi, org.apache.ratis.statemachine.StateMachine.FollowerEventApi, org.apache.ratis.statemachine.StateMachine.LeaderEventApi, org.apache.ratis.statemachine.StateMachine.Registry

Field Summary

Fields inherited from interface org.apache.ratis.statemachine.StateMachine.DataApi

DEFAULT

Fields inherited from interface org.apache.ratis.statemachine.StateMachine.EventApi

DEFAULT

Fields inherited from interface org.apache.ratis.statemachine.StateMachine.LeaderEventApi

DEFAULT

Fields inherited from interface org.apache.ratis.statemachine.StateMachine.FollowerEventApi

DEFAULT

Constructor Summary

Constructors

Constructor and Description
JournalStateMachine(Map<String,RaftJournal> journals, RaftJournalSystem journalSystem, SnapshotDirStateMachineStorage storage)

Method Summary

Modifier and Type	Method and Description
void	applyJournalEntryCommand(org.apache.ratis.statemachine.TransactionContext commit) Applies a journal entry commit to the state machine.
CompletableFuture<org.apache.ratis.protocol.Message>	applyTransaction(org.apache.ratis.statemachine.TransactionContext trx)
CatchupFuture	catchup(long sequence) Initiates catching up of masters to given sequence.
void	close()
long	getLastAppliedCommitIndex()
long	getLastAppliedSequenceNumber()
long	getLastPrimaryStartSequenceNumber()
org.apache.ratis.statemachine.SnapshotInfo	getLatestSnapshot()
org.apache.ratis.statemachine.StateMachineStorage	getStateMachineStorage()
void	initialize(org.apache.ratis.server.RaftServer server, org.apache.ratis.protocol.RaftGroupId groupId, org.apache.ratis.server.storage.RaftStorage raftStorage)
boolean	isSnapshotting()
boolean	isSuspended()
void	notifyConfigurationChanged(long term, long index, org.apache.ratis.proto.RaftProtos.RaftConfigurationProto newRaftConfiguration)
CompletableFuture<org.apache.ratis.server.protocol.TermIndex>	notifyInstallSnapshotFromLeader(org.apache.ratis.proto.RaftProtos.RoleInfoProto roleInfoProto, org.apache.ratis.server.protocol.TermIndex firstTermIndexInLog)
void	notifyLeaderChanged(org.apache.ratis.protocol.RaftGroupMemberId groupMemberId, org.apache.ratis.protocol.RaftPeerId raftPeerId)
void	notifyNotLeader(Collection<org.apache.ratis.statemachine.TransactionContext> pendingEntries)
void	pause()
CompletableFuture<org.apache.ratis.protocol.Message>	query(org.apache.ratis.protocol.Message request)
void	reinitialize()
void	resume() Resumes applying to masters.
void	suspend(Runnable interruptCallback) Suspends applying to masters.
long	takeLocalSnapshot(boolean hasStateLock) Takes a snapshot of local state machine.
long	takeSnapshot()
void	unpause() Unpause the StateMachine.
long	upgrade() Upgrades the journal state machine to primary mode.

Methods inherited from class org.apache.ratis.statemachine.impl.BaseStateMachine

applyTransactionSerial, cancelTransaction, getGroupId, getId, getLastAppliedTermIndex, getLifeCycle, getLifeCycleState, getServer, notifyTermIndexUpdated, preAppendTransaction, queryStale, recordTime, setLastAppliedTermIndex, startTransaction, toString, updateLastAppliedTermIndex

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Methods inherited from interface org.apache.ratis.statemachine.StateMachine

data, event, followerEvent, leaderEvent, toStateMachineLogEntryString

Methods inherited from interface org.apache.ratis.statemachine.StateMachine.DataApi

flush, link, read, stream, truncate, write

Methods inherited from interface org.apache.ratis.statemachine.StateMachine.EventApi

notifyGroupRemove, notifyLogFailed

Methods inherited from interface org.apache.ratis.statemachine.StateMachine.LeaderEventApi

notifyFollowerSlowness

Methods inherited from interface org.apache.ratis.statemachine.StateMachine.FollowerEventApi

notifyExtendedNoLeader

Constructor Detail

JournalStateMachine

public JournalStateMachine(Map<String,RaftJournal> journals,
                           RaftJournalSystem journalSystem,
                           SnapshotDirStateMachineStorage storage)

Parameters:

journals - master journals; these journals are still owned by the caller, not by the journal state machine

journalSystem - the raft journal system

storage - the SnapshotDirStateMachineStorage that this state machine will use

Method Detail

initialize

public void initialize(org.apache.ratis.server.RaftServer server,
                       org.apache.ratis.protocol.RaftGroupId groupId,
                       org.apache.ratis.server.storage.RaftStorage raftStorage)
                throws IOException

Specified by:

initialize in interface org.apache.ratis.statemachine.StateMachine

Overrides:

initialize in class org.apache.ratis.statemachine.impl.BaseStateMachine

Throws:

IOException

reinitialize

public void reinitialize()
                  throws IOException

Specified by:

reinitialize in interface org.apache.ratis.statemachine.StateMachine

Overrides:

reinitialize in class org.apache.ratis.statemachine.impl.BaseStateMachine

Throws:

IOException

takeSnapshot

public long takeSnapshot()

Specified by:

takeSnapshot in interface org.apache.ratis.statemachine.StateMachine

Overrides:

takeSnapshot in class org.apache.ratis.statemachine.impl.BaseStateMachine

getLatestSnapshot

public org.apache.ratis.statemachine.SnapshotInfo getLatestSnapshot()

Specified by:

getLatestSnapshot in interface org.apache.ratis.statemachine.StateMachine

Overrides:

getLatestSnapshot in class org.apache.ratis.statemachine.impl.BaseStateMachine

Returns:

the latest snapshot information, or null of no snapshot exists

getStateMachineStorage

public org.apache.ratis.statemachine.StateMachineStorage getStateMachineStorage()

Specified by:

getStateMachineStorage in interface org.apache.ratis.statemachine.StateMachine

Overrides:

getStateMachineStorage in class org.apache.ratis.statemachine.impl.BaseStateMachine

query

public CompletableFuture<org.apache.ratis.protocol.Message> query(org.apache.ratis.protocol.Message request)

Specified by:

query in interface org.apache.ratis.statemachine.StateMachine

Overrides:

query in class org.apache.ratis.statemachine.impl.BaseStateMachine

close

public void close()

Specified by:

close in interface Closeable

Specified by:

close in interface AutoCloseable

Overrides:

close in class org.apache.ratis.statemachine.impl.BaseStateMachine

applyTransaction

public CompletableFuture<org.apache.ratis.protocol.Message> applyTransaction(org.apache.ratis.statemachine.TransactionContext trx)

Specified by:

applyTransaction in interface org.apache.ratis.statemachine.StateMachine

Overrides:

applyTransaction in class org.apache.ratis.statemachine.impl.BaseStateMachine

notifyNotLeader

public void notifyNotLeader(Collection<org.apache.ratis.statemachine.TransactionContext> pendingEntries)

notifyConfigurationChanged

public void notifyConfigurationChanged(long term,
                                       long index,
                                       org.apache.ratis.proto.RaftProtos.RaftConfigurationProto newRaftConfiguration)

notifyInstallSnapshotFromLeader

public CompletableFuture<org.apache.ratis.server.protocol.TermIndex> notifyInstallSnapshotFromLeader(org.apache.ratis.proto.RaftProtos.RoleInfoProto roleInfoProto,
                                                                                                     org.apache.ratis.server.protocol.TermIndex firstTermIndexInLog)

pause

public void pause()

Specified by:

pause in interface org.apache.ratis.statemachine.StateMachine

Overrides:

pause in class org.apache.ratis.statemachine.impl.BaseStateMachine

unpause

public void unpause()

Unpause the StateMachine. This should be done after uploading new state to the StateMachine.

applyJournalEntryCommand

public void applyJournalEntryCommand(org.apache.ratis.statemachine.TransactionContext commit)

Applies a journal entry commit to the state machine.

Parameters:

commit - the commit

takeLocalSnapshot

public long takeLocalSnapshot(boolean hasStateLock)

Takes a snapshot of local state machine.

Parameters:

hasStateLock - indicates whether this method call is guarded by a state lock

Returns:

the index of last included entry, or RaftLog.INVALID_LOG_INDEX if it fails

suspend

public void suspend(Runnable interruptCallback)
             throws IOException

Suspends applying to masters. When using suspend, the caller needs to provide a callback method as parameter. This callback is invoked when the journal needs to reload and thus cannot suspend the state changes any more. The callback should cancel any tasks that access the master states. After the callback returns, the journal assumes that the states is no longer being accessed and will reload immediately.

Parameters:

interruptCallback - a callback function to be called when the suspend is interrupted

Throws:

IOException - if suspension fails

resume

public void resume()
            throws IOException

Resumes applying to masters.

Throws:

IOException - if resuming fails

catchup

public CatchupFuture catchup(long sequence)

Initiates catching up of masters to given sequence.

Parameters:

sequence - the target sequence

Returns:

the future to track when catching up is done

upgrade

public long upgrade()

Upgrades the journal state machine to primary mode.

Returns:

the last sequence number read while in standby mode

getLastAppliedSequenceNumber

public long getLastAppliedSequenceNumber()

Returns:

the sequence number of the last entry applied to the state machine

getLastPrimaryStartSequenceNumber

public long getLastPrimaryStartSequenceNumber()

Returns:

the last primary term start sequence number applied to this state machine

getLastAppliedCommitIndex

public long getLastAppliedCommitIndex()

Returns:

the last raft log index which was applied to the state machine

isSnapshotting

public boolean isSnapshotting()

Returns:

whether the state machine is in the process of taking a snapshot

notifyLeaderChanged

public void notifyLeaderChanged(org.apache.ratis.protocol.RaftGroupMemberId groupMemberId,
                                org.apache.ratis.protocol.RaftPeerId raftPeerId)

isSuspended

public boolean isSuspended()

Returns:

whether the journal is suspended