The best-tux.cae.wisc.edu service (load-balancing)

A brief overview of best-tux.cae.wisc.edu, a load-balancer to find the next available linux lab machine.

At CAE, we run a service to provide "best-tux.cae.wisc.edu" using a load balancer. This ideally allows users to log in to machines that don't have anyone else logged in, which can help to make sure there are enough cpu and memory resources to handle the needs of the user. You can use the name "best-tux.cae.wisc.edu" just as you would use a normal lab machine name, but it is not a separate machine or server -- you are connected to a normal lab machine in the end.

The "best-tux" service is handled by a DNS service called "lbnamed", which handles requests and returns a DNS response to a specific lab machine (e.g., tux-101.cae.wisc.edu). "Weighting" is the way we can prioritize certain machines or workloads to decide which tux is "best". The lbnamed find the most available lab machine by polling lab machines and weighing the results. The tuxes are scored at different values depending on base score, number of users logged in, how active the machine is, etc.

It is recommended that you use "best-tux.cae.wisc.edu" for remote connections (either ssh or vnc), since connecting directly to a specific machine could result in many users logged in at the same time, and the machine may not perform very well. Different lab machines may also not be available at certain times due to maintenance or because labs are being restructured.

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