On Sat, Mar 31, 2012 at 08:06:23PM -0700, David Birdsong wrote: > On Sat, Mar 31, 2012 at 7:55 PM, Kevin Heatwole <ke...@heatwoles.us> wrote: > > I am just investigating use of haproxy for the first time. > > > > I'd like the balancing algorithm to send http request to the first server > > in the list until the number of requests hits a configurable number. When > > the request limit for a server is hit, I then want new requests to go to > > the next server until that server hits its configurable limit. So, instead > > of RR, I want to load down a server before overflowing to the next server. > > > > What I think I want to do is to always have the last server in the farm not > > have any requests. If it does, I will activate another server to ensure I > > have enough capacity to handle the load spike. But, when the last two > > servers go completely idle again, I can deactivate the last idle server. > > > > My servers are "in the cloud" and I pay for each one that is activated so I > > think this type of load balancing would help me activate only servers I > > need (saving me money). > > > > I would plan to automate this by having all servers included in the haproxy > > config but only the first server would initially be UP and all others DOWN. > > When a server handles a request, it makes sure that its next server is > > activated. When a server doesn't handle any requests for some time, it > > deactivates its next server (if any). > > You could implement this by monitoring your available slots on a > backend, once the slots decrease %N of total slots, spin up new > instances. Apply the same logic in reverse to turn off nodes.
Or you can download latest snapshot and use "balance first", which was proposed by Steen Larsen one month ago :-) Willy
