FD_HOST

java.lang.Object
- com.fr.third.jgroups.stack.Protocol
- - com.fr.third.jgroups.protocols.FD_HOST

```
public class FD_HOST
extends Protocol
```
Failure detection protocol which detects the crash or hanging of entire hosts and suspects all cluster members on those hosts. By default InetAddress.isReachable() is used, but any script/command can be used for liveness checks by defining the 'cmd' property.
FD_HOST does not detect the crash or hanging of single members on the local host, but only checks liveness of all other hosts in a cluster. Therefore it is meant to be used together with other failure detection protocols, e.g. FD_ALL and FD_SOCK.
This protocol would typically be used when multiple cluster members are running on the same physical box.
JIRA: https://issues.jboss.org/browse/JGRP-1855

版本:

3.5, 3.4.5

作者:

Bela Ban

嵌套类概要

嵌套类
限定符和类型	类和说明
`static class`	`FD_HOST.CommandExecutor`
`static class`	`FD_HOST.CommandExecutor2`
`protected static class`	`FD_HOST.ExternalPingCommand`
`static class`	`FD_HOST.IsReachablePingCommand`
`static interface`	`FD_HOST.PingCommand` Command used to check whether a given host is alive, periodically called
`protected class`	`FD_HOST.PingTask` Selected members run this task periodically.

字段概要

字段
限定符和类型	字段和说明
`protected long`	`check_timeout`
`protected java.lang.String`	`cmd`
`protected boolean`	`has_suspected_mbrs`
`protected java.util.Map<java.net.InetAddress,java.util.List<Address>>`	`hosts` Map of hosts and their cluster members, updated on view changes.
`protected long`	`interval`
`protected Address`	`local_addr`
`protected java.net.InetAddress`	`local_host`
`protected java.util.List<Address>`	`members`
`protected int`	`num_liveness_checks`
`protected int`	`num_suspect_events`
`protected FD_HOST.PingCommand`	`ping_command` The command to detect whether a target is alive
`protected java.util.concurrent.Future<?>`	`ping_task_future`
`protected BoundedList<Tuple<java.net.InetAddress,java.lang.Long>>`	`suspect_history`
`protected java.util.Set<Address>`	`suspected_mbrs`
`protected TimeService`	`time_service`
`protected long`	`timeout`
`protected TimeScheduler`	`timer` Timer used to run the ping task on
`protected java.util.concurrent.ConcurrentMap<java.net.InetAddress,java.lang.Long>`	`timestamps`
`protected boolean`	`use_time_service`

从类继承的字段 com.fr.third.jgroups.stack.Protocol
down_prot, ergonomics, id, log, name, stack, stats, up_prot

构造器概要

构造器
构造器和说明

FD_HOST()

构造器
构造器和说明
`FD_HOST()`

方法概要

方法
限定符和类型	方法和说明
`protected java.lang.String`	`_printTimestamps()`
`java.lang.Object`	`down(Event evt)` An event is to be sent down the stack.
`protected long`	`getAgeOf(java.net.InetAddress host)` Returns the age (in secs) of the given host
`protected java.net.InetAddress`	`getHostFor(Address mbr)`
`protected PhysicalAddress`	`getPhysicalAddress(Address logical_addr)`
`java.lang.String`	`getSuspectedMembers()`
`protected long`	`getTimestamp()`
`protected void`	`handleView(View view)`
`void`	`init()` Called after instance has been created (null constructor) and before protocol is started.
`boolean`	`isAlive(java.lang.String host)`
`protected boolean`	`isPinger(Address mbr)`
`boolean`	`isPingerRunning()`
`FD_HOST`	`pingCommand(FD_HOST.PingCommand cmd)`
`java.lang.String`	`printHosts()`
`java.lang.String`	`printSuspectHistory()`
`java.lang.String`	`printTimestamps()`
`void`	`resetStats()`
`void`	`setCommand(java.lang.String command)`
`protected void`	`startPingerTask()`
`void`	`stop()` This method is called on a `Channel.disconnect()`.
`protected void`	`stopPingerTask()`
`protected void`	`suspect(java.net.InetAddress host)` Called by ping task; will result in all members of host getting suspected
`protected void`	`suspect(java.util.List<Address> suspects)`
`protected boolean`	`unsuspect(Address mbr)`
`protected void`	`updateTimestampFor(java.net.InetAddress host)`

从类继承的方法 com.fr.third.jgroups.stack.Protocol
accept, destroy, dumpStats, enableStats, getConfigurableObjects, getDownProtocol, getDownServices, getId, getIdsAbove, getLevel, getName, getProtocolStack, getSocketFactory, getThreadFactory, getTransport, getUpProtocol, getUpServices, getValue, isErgonomics, level, parse, printStats, providedDownServices, providedUpServices, requiredDownServices, requiredUpServices, resetStatistics, setDownProtocol, setErgonomics, setId, setLevel, setProtocolStack, setSocketFactory, setUpProtocol, setValue, setValues, start, statsEnabled, up, up

从类继承的方法 java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- 字段详细资料
  - cmd
```
protected java.lang.String cmd
```
  - timeout
```
protected long timeout
```
  - interval
```
protected long interval
```
  - check_timeout
```
protected long check_timeout
```
  - use_time_service
```
protected boolean use_time_service
```
  - num_liveness_checks
```
protected int num_liveness_checks
```
  - num_suspect_events
```
protected int num_suspect_events
```
  - suspected_mbrs
```
protected final java.util.Set<Address> suspected_mbrs
```
  - has_suspected_mbrs
```
protected volatile boolean has_suspected_mbrs
```
  - suspect_history
```
protected final BoundedList<Tuple<java.net.InetAddress,java.lang.Long>> suspect_history
```
  - local_addr
```
protected Address local_addr
```
  - local_host
```
protected java.net.InetAddress local_host
```
  - members
```
protected final java.util.List<Address> members
```
  - ping_command
```
protected FD_HOST.PingCommand ping_command
```
    The command to detect whether a target is alive
  - hosts
```
protected final java.util.Map<java.net.InetAddress,java.util.List<Address>> hosts
```
    Map of hosts and their cluster members, updated on view changes. Used to suspect all members of a suspected host
  - timestamps
```
protected final java.util.concurrent.ConcurrentMap<java.net.InetAddress,java.lang.Long> timestamps
```
  - timer
```
protected TimeScheduler timer
```
    Timer used to run the ping task on
  - time_service
```
protected TimeService time_service
```
  - ping_task_future
```
protected java.util.concurrent.Future<?> ping_task_future
```
- 构造器详细资料
  - FD_HOST
```
public FD_HOST()
```
- 方法详细资料
  - pingCommand
```
public FD_HOST pingCommand(FD_HOST.PingCommand cmd)
```
  - resetStats
```
public void resetStats()
```
    覆盖:
    
    resetStats 在类中 Protocol
  - setCommand
```
public void setCommand(java.lang.String command)
```
  - printSuspectHistory
```
public java.lang.String printSuspectHistory()
```
  - printTimestamps
```
public java.lang.String printTimestamps()
```
  - isPingerRunning
```
public boolean isPingerRunning()
```
  - printHosts
```
public java.lang.String printHosts()
```
  - isAlive
```
public boolean isAlive(java.lang.String host)
                throws java.lang.Exception
```
    抛出:
    
    java.lang.Exception
  - getSuspectedMembers
```
public java.lang.String getSuspectedMembers()
```
  - init
```
public void init()
          throws java.lang.Exception
```
    从类复制的说明: Protocol
    
    Called after instance has been created (null constructor) and before protocol is started. Properties are already set. Other protocols are not yet connected and events cannot yet be sent.
    
    覆盖:
    
    init 在类中 Protocol
    
    抛出:
    
    java.lang.Exception - Thrown if protocol cannot be initialized successfully. This will cause the ProtocolStack to fail, so the channel constructor will throw an exception
  - stop
```
public void stop()
```
    从类复制的说明: Protocol
    
    This method is called on a Channel.disconnect(). Stops work (e.g. by closing multicast socket). Will be called from top to bottom. This means that at the time of the method invocation the neighbor protocol below is still working. This method will replace the STOP, STOP_OK, CLEANUP and CLEANUP_OK events. The ProtocolStack guarantees that when this method is called all messages in the down queue will have been flushed
    
    覆盖:
    
    stop 在类中 Protocol
  - down
```
public java.lang.Object down(Event evt)
```
    从类复制的说明: Protocol
    
    An event is to be sent down the stack. The layer may want to examine its type and perform some action on it, depending on the event's type. If the event is a message MSG, then the layer may need to add a header to it (or do nothing at all) before sending it down the stack using down_prot.down(). In case of a GET_ADDRESS event (which tries to retrieve the stack's address from one of the bottom layers), the layer may need to send a new response event back up the stack using up_prot.up().
    
    覆盖:
    
    down 在类中 Protocol
  - handleView
```
protected void handleView(View view)
```
  - getPhysicalAddress
```
protected PhysicalAddress getPhysicalAddress(Address logical_addr)
```
  - getHostFor
```
protected java.net.InetAddress getHostFor(Address mbr)
```
  - isPinger
```
protected boolean isPinger(Address mbr)
```
  - startPingerTask
```
protected void startPingerTask()
```
  - stopPingerTask
```
protected void stopPingerTask()
```
  - suspect
```
protected void suspect(java.net.InetAddress host)
```
    Called by ping task; will result in all members of host getting suspected
  - suspect
```
protected void suspect(java.util.List<Address> suspects)
```
  - unsuspect
```
protected boolean unsuspect(Address mbr)
```
  - _printTimestamps
```
protected java.lang.String _printTimestamps()
```
  - updateTimestampFor
```
protected void updateTimestampFor(java.net.InetAddress host)
```
  - getAgeOf
```
protected long getAgeOf(java.net.InetAddress host)
```
    Returns the age (in secs) of the given host
  - getTimestamp
```
protected long getTimestamp()
```

类 FD_HOST

嵌套类概要

字段概要

从类继承的字段 com.fr.third.jgroups.stack.Protocol

构造器概要

方法概要

从类继承的方法 com.fr.third.jgroups.stack.Protocol

从类继承的方法 java.lang.Object

字段详细资料

cmd

timeout

interval

check_timeout

use_time_service

num_liveness_checks

num_suspect_events

suspected_mbrs

has_suspected_mbrs

suspect_history

local_addr

local_host

members

ping_command

hosts

timestamps

timer

time_service

ping_task_future

构造器详细资料

FD_HOST

方法详细资料

pingCommand

resetStats

setCommand

printSuspectHistory

printTimestamps

isPingerRunning

printHosts

isAlive

getSuspectedMembers

init

stop

down

handleView

getPhysicalAddress

getHostFor

isPinger

startPingerTask

stopPingerTask

suspect

suspect

unsuspect

_printTimestamps

updateTimestampFor

getAgeOf

getTimestamp