[Spread-users] Wackamole Release Announcement: N-Way Fail Over for IP addresses in a Cluster

Yair Amir yairamir at cnds.jhu.edu
Wed Aug 29 18:39:45 EDT 2001


We at the Center for Networking and Distributed Systems at Johns Hopkins
(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
which is essentially a version of BSD license with a somewhat stronger

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
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
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
under a similar license) to generate a consistent state that is agreed upon
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 wackamole at backhand.org

        Best regards,

        :) Yair.        http://www.cnds.jhu.edu

Spread-users mailing list
Spread-users at lists.spread.org

More information about the Spread-users mailing list