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FW: wackamole 1.0

  • From: Bill Manning
  • Date: Wed Sep 05 11:03:42 2001

 We interupt the normal NANOG threads for this potentially interesting item.

% -------------------------
% Hi,
% We at the Center for Networking and Distributed Systems at Johns Hopkins
% University
% ( 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: and is released
% under the CNDS open source license
% 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 (, 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
% (,
% adding to its predecessors mod_backhand and mod_log_spread.
% For questions or comments - e-mail [email protected]
%         Best regards,
%         :) Yair.