UCARP and Squeeze

IP fault tolerance on Debian Squeeze couldn’t be easier than with UCARP!:

  • Install UCARP on all nodes:
    apt-get install ucarp
  • Edit /etc/network/interfaces on all nodes, replacing <CLUSTER IP> and <PASSWORD> as appropriate:
    iface eth0 inet static
    ucarp-vid 3
    ucarp-vip <CLUSTER IP>
    ucarp-password <PASSWORD>
    ucarp-xparam -n
    iface eth0:ucarp inet static
    address <CLUSTER IP>
  • Reboot, and you’re done!  <CLUSTER IP> will now be available from one of the nodes in your cluster at all times!

A few notes:

  • All nodes in your UCARP cluster must be in the same subnet, and the shared cluster IP must also be in the same subnet.
  • UCARP does not do cluster resource management for you, but it does provide hooks.  You will need to write some scripts to handle unmounting/mounting of shared storage, etc.
  • UCARP does not detect service failures, only whole-host (or IP stack) failures.  But if you can detect the failure, simply send SIGUSR2 to the ucarp process to force into passive mode, forcing another node to become master.
All-in-all, about as simple and sufficient as one can get!


  1. #1 by 張旭 on 2012-03-26 05:24:54 EST - 2012-03-26T05:24:54+00:00


  2. #2 by bb2kk on 2013-01-28 01:55:58 EST - 2013-01-28T01:55:58+00:00

    Don’t forget that the ucarpid must be a common number in your nodes and unique out of the nodes

  1. Ucarp setup for Debain Squeeze « Varinder Singh

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google+ photo

You are commenting using your Google+ account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

%d bloggers like this: