On 02/22/2011 03:53 PM, Jorn Argelo wrote:
Dear all,
We are investigating a potential migration from Squid to ATS. On the
first look most of the stuff we use Squid for is available in ATS, but
I have a couple of questions about the remaps for a reversed proxy ATS:
1) The documentation states that the port in both URLs must be the
same. If I understand it well, this means I cannot connect to port 80
on ATS and have, for example, port 50888 listening on my origin server
and use ATS to connect to the origin server. Is this correct? If it's
not correct, how would I put it in the remap.config?
The documentation is wrong, blame Igor :). Seriously though, we should
fix that doc bug, this has caused confusion before. You are most
certainly able (and encouraged) to map from one port to the other. I do
this all the time, on my "production" box, to hide Apache HTTPD from
outside access. The map rule would look exactly as you expect, e.g.
map http://www.example.com http://localhost:8888
2) Is there any way of splitting the remap.config in multiple files?
This for manageability of remaps and redirects.
Not right now. At least not inside any of the "core" code. What I'd
suggest (and has been done before) is to do this yourself, e.g. simple do
cat /some/path/*.config >
/usr/local/etc/trafficserver/remap.config && traffic_line -r
3) Squid's cache peer construction allows direct connection to an
origin server using the host header provided by the client. And, based
on the acl, you can let Squid decide to what cache peer it needs to
connect to based on the Host header. How does this work with ATS? I
understood from the documentation that the remap.config is also used
for reversed proxy mode, but I still need to provide a target
(internal) URL. In our current setup the internal and public URL are
the same so I don't think this will work then? Since we have nothing
to fill in as target URL.
Not sure I understand this. You will need to map something like
map http://www.example.com/ http://localhost:8888
The default configuration as of current trunk (might be in v2.1.5 as
well) is to preserve the Host: header as sent to the origin server. you
can override that in records.config (look for the configuration for
"pristine host header").
4) I am still not sure what the use of the reversed_map is and when I
am supposed to use it, even though I read the documentation several
times. Can someone please clarify this?
It's intended to be used when a server return redirects / location
information back to the user, to make sure that the user goes through
the proxy and not directly to the origin server. If you do not produce
any such information (which would be the case if you have the backend
respond / use the same URLs as the proxy, and use pristine host
headers), then it's not an issue. If however the HTTPD daemon could e.g.
return a header with a 302 response and Location: localhost:8888, then
you will need the reverse_map to handle it).
Cheers,
-- leif
