org.apache.cassandra.gms

Class Gossiper

java.lang.Object

org.apache.cassandra.gms.Gossiper

All Implemented Interfaces:

GossiperMBean, IFailureDetectionEventListener

public class Gossiper
extends java.lang.Object
implements IFailureDetectionEventListener, GossiperMBean

This module is responsible for Gossiping information for the local endpoint. This abstraction maintains the list of live and dead endpoints. Periodically i.e. every 1 second this module chooses a random node and initiates a round of Gossip with it. A round of Gossip involves 3 rounds of messaging. For instance if node A wants to initiate a round of Gossip with node B it starts off by sending node B a GossipDigestSynMessage. Node B on receipt of this message sends node A a GossipDigestAckMessage. On receipt of this message node A sends node B a GossipDigestAck2Message which completes a round of Gossip. This module as and when it hears one of the three above mentioned messages updates the Failure Detector with the liveness information. Upon hearing a GossipShutdownMessage, this module will instantly mark the remote node as down in the Failure Detector.

Field Summary

Fields

Modifier and Type	Field and Description
static long	aVeryLongTime
static Gossiper	instance
static int	intervalInMillis
static java.lang.String	MBEAN_NAME
static int	QUARANTINE_DELAY

Method Summary

Modifier and Type	Method and Description
void	addExpireTimeForEndpoint(java.net.InetAddress endpoint, long expireTime)
void	addLocalApplicationState(ApplicationState applicationState, VersionedValue value)
void	addLocalApplicationStates(java.util.List<Pair<ApplicationState,VersionedValue>> states)
void	addSavedEndpoint(java.net.InetAddress ep) Add an endpoint we knew about previously, but whose state is unknown
void	advertiseRemoving(java.net.InetAddress endpoint, java.util.UUID hostId, java.util.UUID localHostId) This method will begin removing an existing endpoint from the cluster by spoofing its state This should never be called unless this coordinator has had 'removenode' invoked
void	advertiseTokenRemoved(java.net.InetAddress endpoint, java.util.UUID hostId) Handles switching the endpoint's state from REMOVING_TOKEN to REMOVED_TOKEN This should only be called after advertiseRemoving
void	assassinateEndpoint(java.lang.String address) Do not call this method unless you know what you are doing.
int	compareEndpointStartup(java.net.InetAddress addr1, java.net.InetAddress addr2) determine which endpoint started up earlier
static long	computeExpireTime()
void	convict(java.net.InetAddress endpoint, double phi) This method is part of IFailureDetectionEventListener interface.
java.util.Map<java.net.InetAddress,EndpointState>	doShadowRound() Do a single 'shadow' round of gossip by retrieving endpoint states that will be stored exclusively in the map return value, instead of endpointStateMap.
protected void	finishShadowRound(java.util.Map<java.net.InetAddress,EndpointState> epStateMap)
void	forceNewerGeneration()
int	getCurrentGenerationNumber(java.net.InetAddress endpoint)
int	getCurrentGenerationNumber(java.lang.String address)
long	getEndpointDowntime(java.net.InetAddress ep)
long	getEndpointDowntime(java.lang.String address)
EndpointState	getEndpointStateForEndpoint(java.net.InetAddress ep)
java.util.Set<java.util.Map.Entry<java.net.InetAddress,EndpointState>>	getEndpointStates()
protected long	getExpireTimeForEndpoint(java.net.InetAddress endpoint)
java.util.UUID	getHostId(java.net.InetAddress endpoint)
java.util.UUID	getHostId(java.net.InetAddress endpoint, java.util.Map<java.net.InetAddress,EndpointState> epStates)
java.util.Set<java.net.InetAddress>	getLiveMembers()
java.util.Set<java.net.InetAddress>	getLiveTokenOwners()
java.util.Set<java.net.InetAddress>	getUnreachableMembers()
java.util.Set<java.net.InetAddress>	getUnreachableTokenOwners()
void	initializeNodeUnsafe(java.net.InetAddress addr, java.util.UUID uuid, int generationNbr)
void	injectApplicationState(java.net.InetAddress endpoint, ApplicationState state, VersionedValue value)
boolean	isAlive(java.net.InetAddress endpoint)
boolean	isDeadState(EndpointState epState)
boolean	isEnabled()
boolean	isGossipOnlyMember(java.net.InetAddress endpoint)
protected boolean	isInShadowRound()
boolean	isKnownEndpoint(java.net.InetAddress endpoint)
boolean	isSafeForBootstrap(java.net.InetAddress endpoint, java.util.Map<java.net.InetAddress,EndpointState> epStates) Check if this endpoint can safely bootstrap into the cluster.
boolean	isSilentShutdownState(EndpointState epState)
protected void	markAsShutdown(java.net.InetAddress endpoint) This method is used to mark a node as shutdown; that is it gracefully exited on its own and told us about it
void	markDead(java.net.InetAddress addr, EndpointState localState)
void	maybeInitializeLocalState(int generationNbr)
void	realMarkAlive(java.net.InetAddress addr, EndpointState localState)
void	register(IEndpointStateChangeSubscriber subscriber) Register for interesting state changes.
void	removeEndpoint(java.net.InetAddress endpoint) Removes the endpoint from Gossip but retains endpoint state
void	replacedEndpoint(java.net.InetAddress endpoint) Remove the Endpoint and evict immediately, to avoid gossiping about this node.
void	replacementQuarantine(java.net.InetAddress endpoint) Quarantine endpoint specifically for replacement purposes.
boolean	seenAnySeed()
void	setLastProcessedMessageAt(long timeInMillis)
void	start(int generationNumber)
void	start(int generationNbr, java.util.Map<ApplicationState,VersionedValue> preloadLocalStates) Start the gossiper with the generation number, preloading the map of application states before starting
void	stop()
void	stopShutdownAndWait(long timeout, java.util.concurrent.TimeUnit unit)
void	unregister(IEndpointStateChangeSubscriber subscriber) Unregister interest for state changes.
void	unsafeAssassinateEndpoint(java.lang.String address)

Methods inherited from class java.lang.Object

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

Field Detail

MBEAN_NAME

public static final java.lang.String MBEAN_NAME

See Also:

Constant Field Values

intervalInMillis

public static final int intervalInMillis

See Also:

Constant Field Values

QUARANTINE_DELAY

public static final int QUARANTINE_DELAY

instance

public static final Gossiper instance

aVeryLongTime

public static final long aVeryLongTime

See Also:

Constant Field Values

Method Detail

setLastProcessedMessageAt

public void setLastProcessedMessageAt(long timeInMillis)

seenAnySeed

public boolean seenAnySeed()

register

public void register(IEndpointStateChangeSubscriber subscriber)

Register for interesting state changes.

Parameters:

subscriber - module which implements the IEndpointStateChangeSubscriber

unregister

public void unregister(IEndpointStateChangeSubscriber subscriber)

Unregister interest for state changes.

Parameters:

subscriber - module which implements the IEndpointStateChangeSubscriber

getLiveMembers

public java.util.Set<java.net.InetAddress> getLiveMembers()

Returns:

a list of live gossip participants, including fat clients

getLiveTokenOwners

public java.util.Set<java.net.InetAddress> getLiveTokenOwners()

Returns:

a list of live ring members.

getUnreachableMembers

public java.util.Set<java.net.InetAddress> getUnreachableMembers()

Returns:

a list of unreachable gossip participants, including fat clients

getUnreachableTokenOwners

public java.util.Set<java.net.InetAddress> getUnreachableTokenOwners()

Returns:

a list of unreachable token owners

getEndpointDowntime

public long getEndpointDowntime(java.net.InetAddress ep)

convict

public void convict(java.net.InetAddress endpoint,
                    double phi)

This method is part of IFailureDetectionEventListener interface. This is invoked by the Failure Detector when it convicts an end point.

Specified by:

convict in interface IFailureDetectionEventListener

Parameters:

endpoint - end point that is convicted.

phi - the value of phi with with ep was convicted

markAsShutdown

protected void markAsShutdown(java.net.InetAddress endpoint)

This method is used to mark a node as shutdown; that is it gracefully exited on its own and told us about it

Parameters:

endpoint - endpoint that has shut itself down

removeEndpoint

public void removeEndpoint(java.net.InetAddress endpoint)

Removes the endpoint from Gossip but retains endpoint state

replacementQuarantine

public void replacementQuarantine(java.net.InetAddress endpoint)

Quarantine endpoint specifically for replacement purposes.

Parameters:

endpoint -

replacedEndpoint

public void replacedEndpoint(java.net.InetAddress endpoint)

Remove the Endpoint and evict immediately, to avoid gossiping about this node. This should only be called when a token is taken over by a new IP address.

Parameters:

endpoint - The endpoint that has been replaced

advertiseRemoving

public void advertiseRemoving(java.net.InetAddress endpoint,
                              java.util.UUID hostId,
                              java.util.UUID localHostId)

This method will begin removing an existing endpoint from the cluster by spoofing its state This should never be called unless this coordinator has had 'removenode' invoked

Parameters:

endpoint - - the endpoint being removed

hostId - - the ID of the host being removed

localHostId - - my own host ID for replication coordination

advertiseTokenRemoved

public void advertiseTokenRemoved(java.net.InetAddress endpoint,
                                  java.util.UUID hostId)

Handles switching the endpoint's state from REMOVING_TOKEN to REMOVED_TOKEN This should only be called after advertiseRemoving

Parameters:

endpoint -

hostId -

unsafeAssassinateEndpoint

public void unsafeAssassinateEndpoint(java.lang.String address)
                               throws java.net.UnknownHostException

Specified by:

unsafeAssassinateEndpoint in interface GossiperMBean

Throws:

java.net.UnknownHostException

assassinateEndpoint

public void assassinateEndpoint(java.lang.String address)
                         throws java.net.UnknownHostException

Do not call this method unless you know what you are doing. It will try extremely hard to obliterate any endpoint from the ring, even if it does not know about it.

Specified by:

assassinateEndpoint in interface GossiperMBean

Parameters:

address -

Throws:

java.net.UnknownHostException

isKnownEndpoint

public boolean isKnownEndpoint(java.net.InetAddress endpoint)

getCurrentGenerationNumber

public int getCurrentGenerationNumber(java.net.InetAddress endpoint)

isGossipOnlyMember

public boolean isGossipOnlyMember(java.net.InetAddress endpoint)

isSafeForBootstrap

public boolean isSafeForBootstrap(java.net.InetAddress endpoint,
                                  java.util.Map<java.net.InetAddress,EndpointState> epStates)

Check if this endpoint can safely bootstrap into the cluster.

Parameters:

endpoint - - the endpoint to check

epStates - - endpoint states in the cluster

Returns:

true if the endpoint can join the cluster

getExpireTimeForEndpoint

protected long getExpireTimeForEndpoint(java.net.InetAddress endpoint)

getEndpointStateForEndpoint

public EndpointState getEndpointStateForEndpoint(java.net.InetAddress ep)

getEndpointStates

public java.util.Set<java.util.Map.Entry<java.net.InetAddress,EndpointState>> getEndpointStates()

getHostId

public java.util.UUID getHostId(java.net.InetAddress endpoint)

getHostId

public java.util.UUID getHostId(java.net.InetAddress endpoint,
                                java.util.Map<java.net.InetAddress,EndpointState> epStates)

compareEndpointStartup

public int compareEndpointStartup(java.net.InetAddress addr1,
                                  java.net.InetAddress addr2)

determine which endpoint started up earlier

realMarkAlive

public void realMarkAlive(java.net.InetAddress addr,
                          EndpointState localState)

markDead

public void markDead(java.net.InetAddress addr,
                     EndpointState localState)

isAlive

public boolean isAlive(java.net.InetAddress endpoint)

isDeadState

public boolean isDeadState(EndpointState epState)

isSilentShutdownState

public boolean isSilentShutdownState(EndpointState epState)

start

public void start(int generationNumber)

start

public void start(int generationNbr,
                  java.util.Map<ApplicationState,VersionedValue> preloadLocalStates)

Start the gossiper with the generation number, preloading the map of application states before starting

doShadowRound

public java.util.Map<java.net.InetAddress,EndpointState> doShadowRound()

Do a single 'shadow' round of gossip by retrieving endpoint states that will be stored exclusively in the map return value, instead of endpointStateMap. Used when preparing to join the ring:

• when replacing a node, to get and assume its tokens
• when joining, to check that the local host id matches any previous id for the endpoint address

Method is synchronized, as we use an in-progress flag to indicate that shadow round must be cleared again by calling finishShadowRound(Map). This will update endpointShadowStateMap with received values, in order to return an immutable copy to the caller of doShadowRound(). Therefor only a single shadow round execution is permitted at the same time.

Returns:

endpoint states gathered during shadow round or empty map

maybeInitializeLocalState

public void maybeInitializeLocalState(int generationNbr)

forceNewerGeneration

public void forceNewerGeneration()

addSavedEndpoint

public void addSavedEndpoint(java.net.InetAddress ep)

Add an endpoint we knew about previously, but whose state is unknown

addLocalApplicationState

public void addLocalApplicationState(ApplicationState applicationState,
                                     VersionedValue value)

addLocalApplicationStates

public void addLocalApplicationStates(java.util.List<Pair<ApplicationState,VersionedValue>> states)

stop

public void stop()

isEnabled

public boolean isEnabled()

finishShadowRound

protected void finishShadowRound(java.util.Map<java.net.InetAddress,EndpointState> epStateMap)

isInShadowRound

protected boolean isInShadowRound()

initializeNodeUnsafe

public void initializeNodeUnsafe(java.net.InetAddress addr,
                                 java.util.UUID uuid,
                                 int generationNbr)

injectApplicationState

public void injectApplicationState(java.net.InetAddress endpoint,
                                   ApplicationState state,
                                   VersionedValue value)

getEndpointDowntime

public long getEndpointDowntime(java.lang.String address)
                         throws java.net.UnknownHostException

Specified by:

getEndpointDowntime in interface GossiperMBean

Throws:

java.net.UnknownHostException

getCurrentGenerationNumber

public int getCurrentGenerationNumber(java.lang.String address)
                               throws java.net.UnknownHostException

Specified by:

getCurrentGenerationNumber in interface GossiperMBean

Throws:

java.net.UnknownHostException

addExpireTimeForEndpoint

public void addExpireTimeForEndpoint(java.net.InetAddress endpoint,
                                     long expireTime)

computeExpireTime

public static long computeExpireTime()

stopShutdownAndWait

public void stopShutdownAndWait(long timeout,
                                java.util.concurrent.TimeUnit unit)
                         throws java.lang.InterruptedException,
                                java.util.concurrent.TimeoutException

Throws:

java.lang.InterruptedException

java.util.concurrent.TimeoutException