Re: 502 proxy error (Apache Users)

On Tue, Nov 4, 2008 at 3:06 PM, Alexandru David Constantinescu <aldavx@xxxxxxxxx> wrote:

isha b wrote:

Thank you all,
I have increased with Keep Alive upto 300 sec as well No KeepAlive option buyt the reult is still negative. Still it is throwing the below error
  *proxy*: *Error reading from remote server returned* by /..."
proxy: error reading status line from remote server

Further I read in groups that the httpd 2.2.3 might have some bugs which is causing the problem. Hence I have upgraded my apache to httpd 2.2.10 . Now the performance is better but still around 40% of the time its end up with proxy error.
my backend server is on ISS and reverse proxy is on Fedora 6 on httpd 2.2.10
  Thanks
Isha


On Thu, Oct 30, 2008 at 7:44 PM, Mehta, Anish <amehta@xxxxxxxxxxxx <mailto:amehta@xxxxxxxxxxxx>> wrote:

Are you using mod_proxy_ajp and load balancing between backend servers?
We used to see this error a lot but when we added timeout parameter to
BalancerMember directive if went away.

You may also want to try this or add the same parameter to ProxyPass
directive (timeout=300).

Regards,
AM

-----Original Message-----
From: Boyle Owen [mailto:Owen.Boyle@xxxxxxxxxxxxx
<mailto:Owen.Boyle@xxxxxxxxxxxxx>]
Sent: Thursday, October 30, 2008 9:31 AM

To: users@xxxxxxxxxxxxxxxx <mailto:users@xxxxxxxxxxxxxxxx>
Subject: RE: 502 proxy error

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From: isha b [mailto:ishaa.b@xxxxxxxxx
<mailto:ishaa.b@xxxxxxxxx>]
Sent: Thursday, October 30, 2008 12:47 PM
To: users@xxxxxxxxxxxxxxxx <mailto:users@xxxxxxxxxxxxxxxx>;
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Subject: 502 proxy error

Team,
When I try to access an application using reverse proxy, most of
the time I will end up with below error. Anybody have an idea what will
be causing the issue? After few refresh on the page I will get actual
page but most of the times end up with below proxy error

Proxy Error
The proxy server received an invalid response from an upstream
server.
The proxy server could not handle the request GET /testingtool/.
Reason: Error reading from remote server

------------------------------------------------------------------------
--------
Apache/2.2.3 (Fedora) Server at testingserver.test.com
<http://testingserver.test.com/> Port 443

Thanks,
Isha

Aoache is the proxy, is it?

It could be the back-end server is not working reliably - what happens
if you access it drectly?

If it seems OK, how long does it take to respond? If it's a slow
application it may take longer than apache is prepared to wait (see
ProxyTimeout, KeepAlivetimeout)

Rgds,
Owen Boyle
Disclaimer: Any disclaimer attached to this message may be ignored.

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I use to have the same problems. My advice is to forget about keepalive at all. This error said that the reverse proxy is unaccessible for proxy . If you take a look in the revers proxy error logs , probably you will see something like "BAD GATEWAY" entries. On the proxy server I use the same version of apache 2.2.10 with

ProxyPass / http://real_server_ip/ disablereuse=On max=1000 ttl=60 timeout=300
And

SetEnv force-proxy-request-1.0 1
SetEnv proxy-nokeepalive 1
SetEnv proxy-initial-not-pooled 1

Disable keepalive on the proxy an real servers too.
With this setings everything seems to be in order for me.Give it a try and see how it works.

alex

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