[svlug] Multiple Web Servers on One IP

[Sargun Dhillon]

Stop using some device that has a terrible queuing method. What might
be better is to run the crappy backend on some port which is 80 bound
to 127.0.0.2 (add this address to lo). Then run the download server
bound to 127.0.0.3. Use a lighty frontend with mod proxy to make
/downloads go to 127.3 and /!downloads to go 127.2. Its just that
simple!

Alternatively you can tell apache to bind to a non-80 port and run a
mod_proxy frontend to sort between the ports.

On Thu, May 29, 2008 at 2:39 PM, Chris Miller
<lordsauronthegreat at gmail.com> wrote:
> I've got what I think is a fairly unique problem based on the lack of
> documentation.  I recently upgraded to a Virtual Private Server, which
> gets me almost every comfort of a full colocation, but without the
> hefty price tag.  It does leave me with no swap file and only 300 MB
> of RAM.  So I've been working to compress my site into as small of a
> space as I can.
>
> I'm using the GForge software package, which eats memory like there's
> no tomorrow.  There's nothing else like it, and it's what I want to
> use, therefore it's not going away.  I worked out how to keep it from
> scaring the other services out of memory by limiting it to only one
> simultaneous server request at a time.  So now pages are served on a
> first-come first-serve basis, and people who make a page request
> during many page requests have to wait for the ones in the queue to
> finish.  This is okay, since each page only takes something like 3
> seconds or so to finish.  The problem comes when downloading stuff.
>
> If someone tries to download a file, that will cause Apache to block
> all page views until that download is finished.  If someone tries
> downloading a 12 MB file over dial up, the web site is effectively
> down for around ten minutes at a time.
>
> Luckily the software I'm using allows me to define another subdomain
> to serve the files, which means another Apache virtual host.  The only
> problem there is that even if I make it two vhosts, Apache still
> interprets this as two vhosts for the memory-eating web application.
> If  I try and download a file while serving a page it works just fine,
> but add a third request and it's straight back to standing in line.
>
> What I want to do is to allow for an unlimited number of concurrent
> connections on the download domain, but keep the web site locked at
> one request at a time.  I looked all through the Apache 2.2 docs and
> found nothing like that.  I don't think it wise to run two instances
> of apache, either.
>
> So I tried LigHTTPD.  It set up fine, and as far as I know it works
> just fine for serving file requests.  It's independent from Apache, so
> it doesn't have a problem allowing as many page requests (file
> downloads) as there are requests, while apache is still limiting
> itself to one request at a time like a good little webserver.
>
> However, I ran into a problem when starting LigHTTPD.  Apache is
> monopolizing the only static IP I get.  I'm was using a name-based
> domain system to get Apache to serve both domains throught the same
> IP.  However, Apache and lighty cannot share the same IP.  I don't
> want to buy another static IP because it costs money.
>
> Is there a way to have both of them share the same IP and still
> differentiate between the domain and the subdomain correctly?  I don't
> want to transfer the whole mess over to lighty, since that'd require
> rewriting a lot of configuration directives that I'm not terribly fond
> of mucking around with.  I tried to find a solution by myself, but
> came up dry.
>
> Just floating a hypothesis, but if I have lighty listening on the
> loopback device, and use Apache to mod_proxy to lo, will that work?
> Will Apache kick the request to the loopback device without blocking
> more page requests?
>
> The client OS is CentoOS 5.1 x86_64.  Thanks for any help you can give
> - these webservers are a real nightmare - almost like you could make a
> whole career out of it.  We could call it "IT"... ;-)
>
> --
> Registered Linux Addict #431495
> http://profile.xfire.com/mrstalinman | John 3:16!
> http://www.fsdev.net/ | http://lordsauron.wordpress.com/
>
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