man ucarp Command

Man page for apt-get ucarp Command

Man Page for ucarp in Linux

This tutorial shows the man page for man ucarp in linux.

Open terminal with 'su' access and type the command as shown below:
man ucarp

Result of the Command Execution shown below:

UCARP(8)                                                              UCARP(8)



NAME
       ucarp    Automatic IP failover

SYNOPSIS
       ucarp [ i,   interface=INTERFACE]  [ s,   srcip=IPADDRESS]
       [ v,   vhid=VHID]  [ p,   pass=PASSWORD]  [ o,   passfile=PASSFILE]
       [ P,   preempt]  [ n,   neutral]  [ a,   addr=IPADDR]  [ h,   help]
       [ b,   advbase=SECS]  [ k,   advskew=SKEW]  [ u,   upscript=SCRIPT]
       [ d,   downscript=SCRIPT]  [ r,   deadratio=RATIO]  [ z,   shutdown]
       [ B,    daemonize]   [ f,    facility=FACILITY]   [ x,    xparam PARAM]
       [ S,   ignoreifstate]  [ M,   nomcast]

DESCRIPTION
       ucarp allows a pair of hosts to share common IP addresses in  order  to
       provide  automatic  failover of an address from one machine to another.
       It is a portable userland implementation of the secure and  patent free
       Common  Address  Redundancy  Protocol, (CARP), OpenBSD's alternative to
       VRRP.

OPTIONS
       ucarp supports the following command line options:

        i INTERFACE   interface=INTERFACE
                 The network interface to bind to.

        s IPADDRESS   srcip=IPADDRESS
                 The persistent source address,  (real  IP),  associated  with
                 this interface.

        v VHID   vhid=VHID
                 The id of the virtual server [1 255].

        p PASSWORD   pass=PASSWORD
                 The  shared password, (this gets encrypted and is not sent in
                 the clear).

        o PASSFILE   passfile=PASSFILE
                 File to read the shared password  from.  The  file  specified
                 should contain the password on the first line of the file.

        P   preempt
                 Turn on preemptive failover. This causes an instance of ucarp
                 to assume master status right immediately.

        n   neutral
                 Do not run the downscript on startup when the  initial  state
                 is backup.

        a IPADDRESS   addr=IPADDRESS
                 The IP address of the virtual server.

        h   help Display a brief summary of the command line options.

        b SECONDS   advbase=SECONDS
                 Interval in seconds that advertisements will occur, (defaults
                 to 1 second).

        k SKEW   advskew=SKEW
                 Advertisement skew [1 255], (defaults to 0).

        u COMMAND   upscript=COMMAND
                 Specifies the command to run  after  ucarp  has  successfully
                 become master, the interface name gets passed as an argument.
                 Typically a script used to bring up the virtual address,  log
                 the result, add routes, clear arp cache entries, etc.

        d COMMAND   downscript=COMMAND
                 Specifies  the  command  that  is run after ucarp has transi 
                 tioned to the backup state, the interface name is  passed  as
                 an  argument.  This  is typically a script used to bring down
                 the virtual interface, log the action, remove routes, etc.

        r RATIO   deadratio=RATIO
                 Ratio used by the backup to determine how long to wait for an
                 unresponsive master before considering it dead.

        z   shutdown
                 Use  of  this  command causes the command specified by the  d
                 argument to be invoked when ucarp shuts down.

        B   daemonize
                 Causes ucarp to detach from the terminal and run in the back 
                 ground as a daemon.

        f   facility
                 Set the syslog facility, defaults to daemon.

        x PARAMETER   xparam=PARAMETER
                 Specify  an  extra  parameter  to  be supplied to the up/down
                 scripts.

        S   ignoreifstate
                 Ignore unplugged network cables. This option is  useful  when
                 ucarp  nodes  are  connected  with a crossover cable. Without
                 this option the master will transition  to  backup  when  the
                 other  node  is powered down, as it no longer has a link (NO 
                 CARRIER).


        M   nomcast
                 Use broadcast instead of multicast advertisements.

EXAMPLES
       A host with a real IP of 10.1.1.10 configured to be  the  master  in  a
       preemptive configuration with a virtual IP of 10.1.1.252.

           ucarp  i eth0  s 10.1.1.10  v 10  p secret  a 10.1.1.252 \
             upscript=/etc/vip up.sh   downscript=/etc/vip down.sh  P

       The backup might be configured something like this.

           ucarp  i eth0  s 10.1.1.11  v 10  p secret  a 10.1.1.252 \
             upscript=/etc/vip up.sh   downscript=/etc/vip down.sh

       A  machine with a real IP of 192.168.1.19 is the preferred master for a
       virtual IP of 10.1.12.7, broadcasts are sent every 5 seconds.

           ucarp  b 5  s 192.168.1.19  v 27  p badpass  a 10.1.12.7 \
            u /etc/vip up.sh  d /etc/vip down.sh  z

       The hot standby with an IP of 192.168.1.20 uses the following  command,
       (note  the  advskew  of  50 putting it at a disadvantage and making the
       first machine preferred).

           ucarp  b 5  k 50  s 192.168.1.20  v 27  p badpass  a 10.1.12.7 \
            u /etc/vip up.sh  d /etc/vip down.sh  z

AUTHOR
       ucarp was written by Frank Denis, .

       This manual page was written by Eric Evans  for  the
       Debian  system  (but  may be used by others).  Permission is granted to
       copy, distribute and/or modify this document under the terms of the GNU
       General Public License, Version 2 or any later version published by the
       Free Software Foundation.


       On Debian systems, the complete text of the GNU General Public  License
       can be found in /usr/share/common licenses/GPL.




                                                                      UCARP(8)

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