You can't add or remove hosts to a pool without doing a reload - you can change the weights, mark them up and down, but not add or remove.
On Mon, May 11, 2015 at 1:00 PM, Nick Couchman <[email protected]> wrote: > I was wondering if it is possible or there's a recommended way to deal > with dynamic capacity expansion for a given back-end. I searched through > the documentation some and didn't see anything obvious, so figured I would > ask here. > > Basically, I would like a way to trigger a script when the number of > active connections gets within a certain range of the total available > connections for the available backend servers. I would like this script to > be able to do something like trigger a script or command that creates or > powers on or off a virtual machine that is already added to or could be > dynamically added to or removed from the back-end. The basic scenario is > this: > - Back-end starts with 10 configured systems or 10 connections each. > - 5 of the 10 systems are powered on by default, with the other 5 down. > - Users connect, and close to 40/50 available connections. > - HAProxy detects the connection limit and triggers a script that starts > up the 6th VM. > - Once HAProxy detects that the 6th VM is running, the number of available > connections moves to 60. > - Users continue to connect and close to 50/60, triggering another power > event. > > I'd also like the reverse of that to happen: > - Users begin to disconnect and connections drop to 40/60. > - HAProxy triggers another script to stop one of the the configured > back-end systems that has zero connections. > > Is this possible? Or on the roadmap? Or something that, while not > implemented directly in the HAProxy configuration could be done some other > way - some periodic polling of HAProxy some other way? > > Thanks, > Nick > > >
