Package org.apache.cassandra.gms

Class 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. This class is not threadsafe and any state changes should happen in the gossip stage.

    • Field Detail

      • QUARANTINE_DELAY

        public static final int QUARANTINE_DELAY

      • instance

        public static final Gossiper instance

      • aVeryLongTime

        public static final long aVeryLongTime

    • Constructor Detail

      • Gossiper

        public Gossiper​(boolean registerJmx)

    • Method Detail

      • clearUnsafe

        public void clearUnsafe()

      • expireUpgradeFromVersion

        public void expireUpgradeFromVersion()

      • 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<InetAddressAndPort> getLiveMembers()
        Returns:
        a list of live gossip participants, including fat clients

      • getLiveTokenOwners

        public java.util.Set<InetAddressAndPort> getLiveTokenOwners()
        Returns:
        a list of live ring members.

      • getUnreachableMembers

        public java.util.Set<InetAddressAndPort> getUnreachableMembers()
        Returns:
        a list of unreachable gossip participants, including fat clients

      • getUnreachableTokenOwners

        public java.util.Set<InetAddressAndPort> getUnreachableTokenOwners()
        Returns:
        a list of unreachable token owners

      • runInGossipStageBlocking

        public static void runInGossipStageBlocking​(java.lang.Runnable runnable)

      • convict

        public void convict​(InetAddressAndPort 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​(InetAddressAndPort 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​(InetAddressAndPort endpoint)
        Removes the endpoint from Gossip but retains endpoint state

      • replacementQuarantine

        public void replacementQuarantine​(InetAddressAndPort endpoint)
        Quarantine endpoint specifically for replacement purposes.
        Parameters:
        endpoint -

      • replacedEndpoint

        public void replacedEndpoint​(InetAddressAndPort 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​(InetAddressAndPort 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​(InetAddressAndPort 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

      • getCurrentGenerationNumber

        public int getCurrentGenerationNumber​(InetAddressAndPort endpoint)

      • isSafeForStartup

        public boolean isSafeForStartup​(InetAddressAndPort endpoint,
                                java.util.UUID localHostUUID,
                                boolean isBootstrapping,
                                java.util.Map<InetAddressAndPort,​EndpointState> epStates)
        Check if this node can safely be started and join the ring. If the node is bootstrapping, examines gossip state for any previous status to decide whether it's safe to allow this node to start and bootstrap. If not bootstrapping, compares the host ID that the node itself has (obtained by reading from system.local or generated if not present) with the host ID obtained from gossip for the endpoint address (if any). This latter case prevents a non-bootstrapping, new node from being started with the same address of a previously started, but currently down predecessor.
        Parameters:
        endpoint - - the endpoint to check
        localHostUUID - - the host id to check
        isBootstrapping - - whether the node intends to bootstrap when joining
        epStates - - endpoint states in the cluster
        Returns:
        true if it is safe to start the node, false otherwise

      • getExpireTimeForEndpoint

        protected long getExpireTimeForEndpoint​(InetAddressAndPort endpoint)

      • inJustRemovedEndpoints

        public boolean inJustRemovedEndpoints​(InetAddressAndPort ep)

      • getEndpoints

        public com.google.common.collect.ImmutableSet<InetAddressAndPort> getEndpoints()

      • getEndpointCount

        public int getEndpointCount()

      • getApplicationState

        public java.lang.String getApplicationState​(InetAddressAndPort endpoint,
                                            ApplicationState state)
        The value for the provided application state for the provided endpoint as currently known by this Gossip instance.
        Parameters:
        endpoint - the endpoint from which to get the endpoint state.
        state - the endpoint state to get.
        Returns:
        the value of the application state state for endpoint, or null if either endpoint is not known by Gossip or has no value for state.

      • isDeadState

        public boolean isDeadState​(EndpointState epState)

      • isSilentShutdownState

        public boolean isSilentShutdownState​(EndpointState epState)

      • isAdministrativelyInactiveState

        public boolean isAdministrativelyInactiveState​(EndpointState epState)

      • isAdministrativelyInactiveState

        public boolean isAdministrativelyInactiveState​(InetAddressAndPort endpoint)

      • 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<InetAddressAndPort,​EndpointState> doShadowRound​(java.util.Set<InetAddressAndPort> peers)
        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 maybeFinishShadowRound(InetAddressAndPort, boolean, 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.
        Parameters:
        peers - Additional peers to try gossiping with.
        Returns:
        endpoint states gathered during shadow round or empty map

      • reloadSeeds

        public java.util.List<java.lang.String> reloadSeeds()
        JMX interface for triggering an update of the seed node list.
        Specified by:
        reloadSeeds in interface GossiperMBean

      • getSeeds

        public java.util.List<java.lang.String> getSeeds()
        JMX endpoint for getting the list of seeds from the node
        Specified by:
        getSeeds in interface GossiperMBean

      • maybeInitializeLocalState

        public void maybeInitializeLocalState​(int generationNbr)

      • forceNewerGeneration

        public void forceNewerGeneration()

      • addSavedEndpoint

        public void addSavedEndpoint​(InetAddressAndPort ep)
        Add an endpoint we knew about previously, but whose state is unknown

      • stop

        public void stop()

      • isEnabled

        public boolean isEnabled()

      • isInShadowRound

        public boolean isInShadowRound()

      • initializeUnreachableNodeUnsafe

        public void initializeUnreachableNodeUnsafe​(InetAddressAndPort addr)
        Creates a new dead EndpointState that is empty. This is used during host replacement for edge cases where the seed notified that the endpoint was empty, so need to add such state into gossip explicitly (as empty endpoints are not gossiped outside of the shadow round). see CASSANDRA-16213

      • initializeNodeUnsafe

        public void initializeNodeUnsafe​(InetAddressAndPort addr,
                                 java.util.UUID uuid,
                                 int generationNbr)

      • initializeNodeUnsafe

        public void initializeNodeUnsafe​(InetAddressAndPort addr,
                                 java.util.UUID uuid,
                                 int netVersion,
                                 int generationNbr)

      • 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​(InetAddressAndPort endpoint,
                                     long expireTime)

      • computeExpireTime

        public static long computeExpireTime()

      • getReleaseVersionsWithPort

        public java.util.Map<java.lang.String,​java.util.List<java.lang.String>> getReleaseVersionsWithPort()
        Description copied from interface: GossiperMBean
        Returns each node's database release version
        Specified by:
        getReleaseVersionsWithPort in interface GossiperMBean

      • getSchemaVersion

        @Nullable
public java.util.UUID getSchemaVersion​(InetAddressAndPort ep)

      • waitToSettle

        public static void waitToSettle()

      • waitForSchemaAgreement

        public boolean waitForSchemaAgreement​(long maxWait,
                                      java.util.concurrent.TimeUnit unit,
                                      java.util.function.BooleanSupplier abortCondition)
        Blockingly wait for all live nodes to agree on the current schema version.
        Parameters:
        maxWait - maximum time to wait for schema agreement
        unit - TimeUnit of maxWait
        Returns:
        true if agreement was reached, false if not

      • hasMajorVersion3OrUnknownNodes

        public boolean hasMajorVersion3OrUnknownNodes()
        Returns false only if the information about the version of each node in the cluster is available and ALL the nodes are on 4.0+ (regardless of the patch version).

      • isUpgradingFromVersionLowerThan

        public boolean isUpgradingFromVersionLowerThan​(CassandraVersion referenceVersion)
        Returns true if there are nodes on version lower than the provided version

      • 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

      • getMinVersion

        @Nullable
public CassandraVersion getMinVersion​(long delay,
                                      java.util.concurrent.TimeUnit timeUnit)

      • unsafeSetEnabled

        public void unsafeSetEnabled()

      • unsafeClearRemoteState

        public java.util.Collection<InetAddressAndPort> unsafeClearRemoteState()

      • unsafeSendLocalEndpointStateTo

        public void unsafeSendLocalEndpointStateTo​(InetAddressAndPort ep)

      • compareGossipAndTokenMetadata

        public java.util.Map<java.lang.String,​java.util.List<java.lang.String>> compareGossipAndTokenMetadata()
        Description copied from interface: GossiperMBean
        Returns a map of endpoints that don't have matching tokenMetadata to gossip tokens. Values are lists of fixed size two (as Pair is not jmx safe), the first is the gossip tokens, the second tokenMetadata).
        Specified by:
        compareGossipAndTokenMetadata in interface GossiperMBean