That's something I considered, but the ultimate problem is that the backend
service we're running (gearman) sometimes gets backed up with requests from
our web servers. In this case, the server still looks 'up' (I *think*) but
requests from PHP scripts are held up waiting for the gearman server to
process the request and close the connection. So having the backup server
option in this case wouldn't work, I don't think, *unless* 'backup' servers
in haproxy will cut in if the maxconn setting is exceeded. If that's the
case, then I suppose we could set the maxconn limit to a low setting and
have the queue option. Do you know if this behaviour exists in haproxy for
backup servers?
Thanks,
Guy
On Mon, Mar 14, 2011 at 5:34 PM, David Birdsong <david.birds...@gmail.com>wrote:
> On Mon, Mar 14, 2011 at 8:15 PM, g...@desgames.com <g...@desgames.com>
> wrote:
> > Actually, I should clarify something. We don't really actually want the
> > 'black hole' situation I described - instead, what we want is for haproxy
> to
> > accept and queue the messages that come in from the requesting server,
> but
> > to still deliver them when a backend server becomes available. In this
> way,
> > the requesting process can continue executing and not having to wait for
> a
> > response. Obviously, we intend to do this only for async type calls.
>
> super hacky, but how about setting up an xinetd service as a backup
> server. haproxy switches connections over only when your service is
> unavailable.
>
> the xinetd service could capture each request and play them back
> later..this service could be as simple as a script:
>
> #!/bin/sh
> REPLAY_LOG_DIR=/var/replay_logs
> cat >> ${REPLAY_LOG_DIR}/$(date +%Y_%m_%d)
>
>
> >
> > On Mon, Mar 14, 2011 at 4:52 PM, g...@desgames.com <g...@desgames.com>
> wrote:
> >>
> >> Hi,
> >>
> >> We have a tcp service we'd like to proxy requests to, and we were
> >> investigating haproxy as a possible solution for our requirements. So
> far,
> >> it doesn't seem like haproxy is suitable but I thought I'd run it by the
> >> community to confirm what I understand to be the case.
> >>
> >> What we want is a proxy that will accept tcp connections on a specific
> >> port and always send a tcp 'ok' response to the requesting process
> whether
> >> or not there is a backend server available. If a backend server (we only
> >> plan on having one at the moment) is available then we want the request
> >> passed transparently through to the backend server. If the backend
> server is
> >> *not* available, then we want haproxy to operate as a kind of 'black
> hole',
> >> and just accept whatever is sent to it, dumping it to the equivalent of
> >> /dev/null. Basically, acting as an equivalent of the backend server.
> >>
> >> Is the above possible with haproxy? Based on what I've read in the
> >> configuration documentation, the answer is no. However, there are a
> *lot* of
> >> options in there so I thought perhaps there's some obscure setting which
> >> would allow this to work.
> >>
> >> Alternatively, does anyone know of a utility that could do what we want?
> >>
> >> Thanks,
> >> Guy
> >
> >
> >
> > --
> > Guy Knights
> > Systems Administrator
> > DES Games
> > www.desgames.com
> > g...@desgames.com
> >
>
--
Guy Knights
Systems Administrator
DES Games
www.desgames.com
g...@desgames.com
