[geeks] wackamole for server failover/load balancing.

[Fogg, James]

There was a thread around here about webserver directors/big-ip/cisco
content switch for making a group of web servers load balance to a single IP
and provide failover if one/some dies. Specifically Bill was looking for a
cheap/free solution.

This may or may not be a solution (no time for research) but it sounds
interesting. It is from a post in the nanog list.


% Hi,
% 
% We at the Center for Networking and Distributed Systems at Johns Hopkins
% University
% (http://www.cnds.jhu.edu) are happy to announce the release of Wackamole,
% a software tool that provides N-Way Fail Over for IP Addresses in a
cluster.
% It is available here: http://www.backhand.org/wackamole/ and is released
% under the CNDS open source license
% http://www.backhand.org/wackamole/LICENSE.shtml
% which is essentially a version of BSD license with a somewhat stronger
% advertising 
% requirement.
% 
% Wackamole is a tool that helps with making a cluster highly available.
% It manages a bunch of virtual IPs that should be available to the outside 
% world at all times. Wackamole ensures that exactly one machine within the
% cluster is 
% listening on each virtual IP address that Wackamole manages. 
% If it discovers that particular machines within the cluster are not alive,
% it will 
% almost immediately ensure that other machines acquire the virtual IP
% addresses the 
% down machines were managing. At no time will more than one connected
machine
% be 
% responsible for any virtual IP. 
% 
% Wackamole also works toward achieving a balanced distribution of the
public
% IPs 
% within the cluster it manages. 
% 
% How it works:
% Wackamole runs as root on each of the cluster's machines. It uses the
% membership 
% notifications provided by the Spread Toolkit (http://www.spread.org, also
% available
% under a similar license) to generate a consistent state that is agreed
upon
% among 
% all of the connected Wackamole instances. 
% Wackamole uses this knowledge to ensure that all of the public IP
addresses
% served 
% by the cluster will be covered by exactly one Wackamole instance. 
% 
% Wackamole is the newest component in the Backhand project
% (http://www.backhand.org),
% adding to its predecessors mod_backhand and mod_log_spread.
% 
% For questions or comments - e-mail wackamole at backhand.org
% 
%         Best regards,
% 
%         :) Yair.        http://www.cnds.jhu.edu