Package: ucarp Version: 1.1 Revision: 11 Depends: libpcap-shlibs BuildDepends: gawk, libpcap Description: Userland CARP, alternative to the VRRP DescDetail: << UCARP allows a pair of hosts to share common virtual IP addresses in order to provide automatic failover. It is a portable userland implementation of the secure and patent-free Common Address Redundancy Protocol (CARP, OpenBSD's alternative to the VRRP). Strong points of the CARP protocol are : very low overhead, cryptographically signed messages, interoperability between different operating systems and no need for any dedicated extra network link between redundant hosts. << DescPort: << ------------------------ USAGE ------------------------ The server will usually be installed as : /sw/sbin/ucarp Everything is driven through command-line options. In order to see the list of available options, try : /sw/sbin/ucarp -h Better than a long technical discussion, here's a real-life setup example. This is tailored for Linux and merely shows the concept. Your company has an internal mail relay whose IP address is 10.1.1.252. Every user has configured his mail client with that host or IP address and the service must always be up and running without reconfiguring mail clients in case of a failure. It's why you set up two mail servers hosts with an identical configuration. Their real IP addresses are 10.1.1.1 and 10.1.1.2. Let's see how to assign the same additionnal IP address (10.1.1.252) to both servers, so that when one goes down, the other one goes up. Right. What we need now is an identifier for the virtual IP. Let's take "42". And we also need a password. Let's take "love". Now, on the first host (whoose real IP is 10.1.1.1), run : /sw/sbin/ucarp -v 42 -p love -a 10.1.1.252 -s 10.1.1.1 & On the second host, whose real IP is 10.1.1.2, run : /sw/sbin/ucarp -v 42 -p love -a 10.1.1.252 -s 10.1.1.2 & You should see that one of those hosts quickly becomes the master, and the other one the backup. Related scripts are spawned on change. Now unplug the master. After a few seconds, the other host becomes the new master. By changing the base (the -b switch) you can have a "preferred" master. The lower the value is, the more likely it's going to be a master. Please note that by default, and if everything's ok, a master will stay a master as long as possible. If you want a "preferred" master to immediately become a master even if the other host is, add the --preempt (or -P) switch. The "dead ratio" (--deadratio=...) knob basically changes how long a backup server will wait for an unresponsive master before considering it as dead, and becoming the new master. In the original protocol, the ratio is 3. This is also the default when this command-line switch is missing. << License: BSD Source: http://www.pureftpd.org/ucarp/%n-%v.tar.bz2 Source-MD5: f907752bd1654a6e8aa42e717aee9774 DocFiles: AUTHORS COPYING ChangeLog INSTALL.txt NEWS README PatchScript: << mv INSTALL INSTALL.txt << SetLDFLAGS: -L%p/lib SetCFLAGS: -no-cpp-precomp ConfigureParams: --prefix=%p --mandir=%d/share/man infodir=%d/share/info CompileScript: << ./configure %c make << InstallScript: << #!/bin/sh -ex echo -e "I am calling make install now" make install DESTDIR=%d << Homepage: http://www.ucarp.org/ Maintainer: Darian Lanx