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The example ucarp config for a virtual IP for Debian/Ubuntu is in /usr/share/doc/ucarp/README.Debian and is as follows:

The recommended method for configuring ucarp is via 
/etc/network/interfaces. For example:

iface eth0 inet static
        ucarp-vid 3
        ucarp-password 16charsatmost
        ucarp-advskew 0
        ucarp-advbase 1
        ucarp-master yes
iface eth0:ucarp inet static

In the document it isn't clear how or if it is possible to configure multiple VIPs on a single interface with this configuration method. Does anyone know if this is possible?

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The author of the debian article mentions that he should incorporate it in a comment at… , so I might have to do it on my own for now ... – Kyle Brandt Sep 8 '10 at 17:38
up vote 0 down vote accepted

Yes this is possible, we are currently using this for a number of production sites.

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You can do any/all of that stuff with debian's interfaces file by using up/down commands.

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For CARP in OpenBSD (where this is ported from, for Linux) I know you would generally configure multiple CARP interfaces, as needed. I haven't tried multiple vIP's on a single interface though, as I haven't had such a need.

However UCARP works in Linux for configuring CARP interfaces (assuming it still uses CARP interfaces in Linux) then couldn't you just create another interface or use it on an eth: alias if not?

Just a thought, but from what I see so far, UCARP appears to be limited in comparison to native CARP in OpenBSD. Why not switch and get a plethora of more goodies? =)

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It's just an issue with the Debian "contrivance" for the configuration of interfaces. UCARP can handle running multiple VIPs on one interface just fine, but Debian's configuration files don't have the "fidelity" to configure it. (I'm more of a CentOS guy, where configuring multiple VIPs on the same interface is a piece of cake... >smile<) – Evan Anderson Sep 9 '10 at 16:59

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