FD_SOCK

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org.jgroups.protocols
Class FD_SOCK

java.lang.Object
  org.jgroups.stack.Protocol
      org.jgroups.protocols.FD_SOCK

All Implemented Interfaces:: java.lang.Runnable

public class FD_SOCK
extends org.jgroups.stack.Protocol
implements java.lang.Runnable

Failure detection protocol based on sockets. Failure detection is ring-based. Each member creates a server socket and announces its address together with the server socket's address in a multicast. A pinger thread will be started when the membership goes above 1 and will be stopped when it drops below 2. The pinger thread connects to its neighbor on the right and waits until the socket is closed. When the socket is closed by the monitored peer in an abnormal fashion (IOException), the neighbor will be suspected.

The main feature of this protocol is that no ping messages need to be exchanged between any 2 peers, and failure detection relies entirely on TCP sockets. The advantage is that no activity will take place between 2 peers as long as they are alive (i.e. have their server sockets open). The disadvantage is that hung servers or crashed routers will not cause sockets to be closed, therefore they won't be detected. The FD_SOCK protocol will work for groups where members are on different hosts

The costs involved are 2 additional threads: one that monitors the client side of the socket connection (to monitor a peer) and another one that manages the server socket. However, those threads will be idle as long as both peers are running.

Nested Class Summary

private class FD_SOCK.BroadcastTask
          Task that periodically broadcasts a list of suspected members to the group.

private static class FD_SOCK.ClientConnectionHandler
          Handles a client connection; multiple client can connect at the same time

static class FD_SOCK.FdHeader


private class FD_SOCK.ServerSocketHandler
          Handles the server-side of a client-server socket connection.

Field Summary

private static int ABNORMAL_TEMINATION


(package private) FD_SOCK.BroadcastTask bcast_task


(package private) java.util.Hashtable cache


(package private) org.jgroups.util.Promise get_cache_promise


(package private) long get_cache_retry_timeout


(package private) long get_cache_timeout


(package private) boolean got_cache_from_coord


(package private) org.jgroups.Address local_addr


(package private) java.util.Vector members


private static java.lang.String name


private static int NORMAL_TEMINATION


(package private) int num_suspect_events


(package private) int num_tries


(package private) org.jgroups.util.Promise ping_addr_promise


(package private) org.jgroups.Address ping_dest


(package private) java.io.InputStream ping_input


(package private) java.net.Socket ping_sock


(package private) java.util.Vector pingable_mbrs


(package private) java.lang.Thread pinger_thread


(package private) boolean regular_sock_close


(package private) java.lang.Object sock_mutex


(package private) java.net.ServerSocket srv_sock


(package private) org.jgroups.stack.IpAddress srv_sock_addr


(package private) java.net.InetAddress srv_sock_bind_addr


(package private) FD_SOCK.ServerSocketHandler srv_sock_handler


(package private) boolean srv_sock_sent


(package private) int start_port
          Start port for server socket (uses first available port starting at start_port).

(package private) org.jgroups.util.BoundedList suspect_history


(package private) long suspect_msg_interval


(package private) org.jgroups.util.TimeScheduler timer


Fields inherited from class org.jgroups.stack.Protocol

down_handler, down_prot, down_queue, down_thread, down_thread_prio, log, observer, props, stack, stats, trace, up_handler, up_prot, up_queue, up_thread, up_thread_prio, warn

Constructor Summary

FD_SOCK()


Method Summary

(package private) void broadcastSuspectMessage(org.jgroups.Address suspected_mbr)
          Sends a SUSPECT message to all group members.

(package private) void broadcastWhoHasSockMessage(org.jgroups.Address mbr)


(package private) org.jgroups.Address determineCoordinator()


(package private) org.jgroups.Address determinePingDest()


void down(org.jgroups.Event evt)
          An event is to be sent down the stack.

(package private) org.jgroups.stack.IpAddress fetchPingAddress(org.jgroups.Address mbr)
          Attempts to obtain the ping_addr first from the cache, then by unicasting q request to mbr, then by multicasting a request to all members.

(package private) void getCacheFromCoordinator()
          Determines coordinator C.

java.lang.String getLocalAddress()


java.lang.String getMembers()


java.lang.String getName()


int getNumSuspectEventsGenerated()


java.lang.String getPingableMembers()


java.lang.String getPingDest()


(package private) void handleSocketClose(java.lang.Exception ex)


void init()
          Called after instance has been created (null constructor) and before protocol is started.

(package private) void interruptPingerThread()
          Interrupts the pinger thread.

java.lang.String printSuspectHistory()


void resetStats()


void run()
          Runs as long as there are 2 members and more.

(package private) void sendIHaveSockMessage(org.jgroups.Address dst, org.jgroups.Address mbr, org.jgroups.stack.IpAddress addr)
          Sends or broadcasts a I_HAVE_SOCK response.

boolean setProperties(java.util.Properties props)
          Configures the protocol initially.

(package private) boolean setupPingSocket(org.jgroups.stack.IpAddress dest)
          Creates a socket to dest, and assigns it to ping_sock.

(package private) void startPingerThread()


(package private) void startServerSocket()


void stop()
          This method is called on a Channel.disconnect()>Channel.disconnect() 55 .

(package private) void stopPingerThread()


(package private) void stopServerSocket()


(package private) void teardownPingSocket()


void up(org.jgroups.Event evt)
          An event was received from the layer below.

Methods inherited from class org.jgroups.stack.Protocol

destroy, downThreadEnabled, dumpStats, enableStats, getDownProtocol, getDownQueue, getProperties, getUpProtocol, getUpQueue, handleSpecialDownEvent, isTrace, isWarn, passDown, passUp, printStats, providedDownServices, providedUpServices, receiveDownEvent, receiveUpEvent, requiredDownServices, requiredUpServices, setDownProtocol, setObserver, setPropertiesInternal, setProtocolStack, setTrace, setUpProtocol, setWarn, start, startDownHandler, startUpHandler, statsEnabled, stopInternal, upThreadEnabled

Methods inherited from class java.lang.Object

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

Field Detail

get_cache_timeout

long get_cache_timeout

get_cache_retry_timeout

final long get_cache_retry_timeout

See Also:: Constant Field Values

suspect_msg_interval

long suspect_msg_interval

num_tries

int num_tries

members

final java.util.Vector members

srv_sock_sent

boolean srv_sock_sent

pingable_mbrs

final java.util.Vector pingable_mbrs

get_cache_promise

final org.jgroups.util.Promise get_cache_promise

got_cache_from_coord

boolean got_cache_from_coord

local_addr

org.jgroups.Address local_addr

srv_sock

java.net.ServerSocket srv_sock

srv_sock_bind_addr

java.net.InetAddress srv_sock_bind_addr

srv_sock_handler

FD_SOCK.ServerSocketHandler srv_sock_handler

srv_sock_addr

org.jgroups.stack.IpAddress srv_sock_addr

ping_dest

org.jgroups.Address ping_dest

ping_sock

java.net.Socket ping_sock

ping_input

java.io.InputStream ping_input

pinger_thread

java.lang.Thread pinger_thread

cache

final java.util.Hashtable cache

start_port

int start_port

Start port for server socket (uses first available port starting at start_port). A value of 0 (default) picks a random port

ping_addr_promise

final org.jgroups.util.Promise ping_addr_promise

sock_mutex

final java.lang.Object sock_mutex

timer

org.jgroups.util.TimeScheduler timer

bcast_task

final FD_SOCK.BroadcastTask bcast_task

regular_sock_close

boolean regular_sock_close

num_suspect_events

int num_suspect_events

NORMAL_TEMINATION

private static final int NORMAL_TEMINATION

See Also:: Constant Field Values

ABNORMAL_TEMINATION

private static final int ABNORMAL_TEMINATION

See Also:: Constant Field Values

name

private static final java.lang.String name

See Also:: Constant Field Values

suspect_history

org.jgroups.util.BoundedList suspect_history

Constructor Detail

FD_SOCK

public FD_SOCK()

Method Detail

getName

public java.lang.String getName()

getLocalAddress

public java.lang.String getLocalAddress()

getMembers

public java.lang.String getMembers()

getPingableMembers

public java.lang.String getPingableMembers()

getPingDest

public java.lang.String getPingDest()

getNumSuspectEventsGenerated

public int getNumSuspectEventsGenerated()