You might be right that the best way to do dynamic configuration is to have a tool from a third-party (or created in house) that does monitoring of the backend servers and edits the config file itself and reloads haproxy.
I just don't want the hassle of finding such tools or writing my own. Maybe haproxy could contain such a tool that is separate from haproxy but maintained, tested, and delivered with haproxy. I have to admit that I haven't researched any of the tools you use. I should do that, but I always worry about creating a new dependency on a new tool since these tools are usually available for free and could lose support and maintenance at any time. HAProxy already has some support for dynamic configuration in the health checks that mark down/up a server depending on the result of the health check. I figure it is relatively simple to build configuration checks on top of the health checks since most of the hard work has already been done for health checks. On Jan 9, 2013, at 5:34 PM, Zachary Stern <z...@enternewmedia.com> wrote: > Right, and my point is that you can make it dynamic without changing the way > haproxy itself works. What your asking for seems like making haproxy itself > overcomplicated, especially for people with simple deployments. But hey, > maybe I'm 100% wrong. In fact, let's operate on that assumption. > > > On Wed, Jan 9, 2013 at 5:26 PM, Kevin Heatwole <ke...@heatwoles.us> wrote: > I guess I wasn't clear again. I'm not talking about "editing" the > configuration file and reloading HAProxy. > > My suggestion is simply to implement a dynamic interface to the backend > servers so they can change the current behavior of the HAProxy instance > (especially in a load balanced HAProxy backend). > > I'll leave it to the developers to figure out what can be dynamically changed > and if adding a server to a backend is too complex, then that won't be part > of the interface. > > On Jan 9, 2013, at 5:18 PM, Zachary Stern <z...@enternewmedia.com> wrote: > >> I understood completely KT. It's perfectly possible to add new lines to the >> haproxy config dynamically and automatically using things like puppet. >> >> E.g. my iptables configurations are dyanmically generated as I spin up new >> servers, using puppet and the rackspace API. You could do something similar, >> regardless of cloud or not. >> >> When I spin up a new server, it's connected to puppet, tagged as a certain >> kind of server, and dynamically added as a backend to haproxy if appropriate. >> >> >> On Wed, Jan 9, 2013 at 5:16 PM, KT Walrus <ke...@my.walr.us> wrote: >> I think you might have misunderstood. By "adding new server", I mean to add >> it as a server in HAProxy configuration. That is, the effect is to add the >> "server" line for the new server into the config file. This has nothing to >> do with launching the server in the cloud. It is the reverse of marking a >> server DOWN, except that the server being marked UP was not originally >> included in the list of servers for the HAProxy backend. >> >> On Jan 9, 2013, at 4:21 PM, Zachary Stern <z...@enternewmedia.com> wrote: >> >>> >>> >>> On Wed, Jan 9, 2013 at 4:13 PM, Kevin Heatwole <ke...@heatwoles.us> wrote: >>> 4. Adding new server to backend by having configuration check return new >>> server configuration. >>> >>> I don't know about the other features, but this one I think violates the >>> UNIX philosophy of "do one thing and do it well". There are already plenty >>> of tools you can use to achieve this with HAproxy, like puppet or chef, and >>> things like the ruby fog gem for cloud provisioning, etc. >>> >>> >>> -- >>> >>> zachary alex stern I systems architect >>> >>> o: 212.363.1654 x106 | f: 212.202.6488 | z...@enternewmedia.com >>> >>> 60-62 e. 11th street, 4th floor | new york, ny | 10003 >>> >>> www.enternewmedia.com >>> >> >> >> >> >> -- >> >> zachary alex stern I systems architect >> >> o: 212.363.1654 x106 | f: 212.202.6488 | z...@enternewmedia.com >> >> 60-62 e. 11th street, 4th floor | new york, ny | 10003 >> >> www.enternewmedia.com >> > > > > > -- > > zachary alex stern I systems architect > > o: 212.363.1654 x106 | f: 212.202.6488 | z...@enternewmedia.com > > 60-62 e. 11th street, 4th floor | new york, ny | 10003 > > www.enternewmedia.com >
