I currently have a server deployment in which Pound is being used as a reverse proxy (HTTPS -> HTTP) in front of a single server instance. I'd like to add a second instance on a different host that acts as a hot-spare in the event that the main instance is down for any reason. I don't want any traffic whatsoever directed to the second server instance when the first instance is up.
From the documentation it seems that adding a second BackEnd entry into the Service block in pound.cfg will cause pound to monitor and load-balance between the two hosts, but I'm not seeing any options that would let me control how pound load-balances, or more specifically, instruct pound to only use 'host 2' when 'host 1' is down.
Is it possible to do this using pound? If not, are there any other open-source tools that would be better suited to this use-case?
Found the option I was looking for. The
Serviceblock can also contain one or moreEmergencyentries for hosts that should only be used if all precedingBackEndnodes are down, which is exactly what I want.Some good reference material is available here: https://calomel.org/pound.html