RE: [us...@httpd] mod_proxy issue - intermittent 502 response
502 is bad gateway, which means that apache and the back-end server have got into a protocol argument. Usually this is due to a bad response from the back-end (as your log entries indicate). Why do you think apache is the problem? Rgds, Owen Boyle Disclaimer: Any disclaimer attached to this message may be ignored. From: Cristian Pini [mailto:cris.p...@fsite.com] Sent: Thursday, November 26, 2009 6:19 PM To: users@httpd.apache.org Subject: [us...@httpd] mod_proxy issue - intermittent 502 response Hi, I'm running Apache/2.0.52 as a reverse proxy on a RHE4 box, the backend app server is on a separate machine again RHE4, running Apache/2.0.52 and mod_perl 1.99_16. There are intermittent 502 responses being generated by the proxy although a page refresh generally resolves the issue, we are trying to get a configuration of 2 RP boxes in front of 3 mod_perl app servers into production but will need to understand / resolve the issue of these intermittent 502 responses first. [Thu Nov 26 15:35:09 2009] [error] [client 88.96.233.45] proxy: error reading status line from remote server xxx.xx.co.uk, referer: http://xxx..co.uk/mens/casual/casual/71/brand-/all-/start- [Thu Nov 26 15:35:09 2009] [error] [client 88.96.233.45] proxy: Error reading from remote server returned by /mens/smart/smart/70/brand-/all-/start-, referer: http://.xxx.co.uk/mens/casual/casual/71/brand-/all-/start- Can someone shed further light on what the problem is and how to resolve it pls, I'm happy to send virtual host confs if someone wishes to dig little deeper. Note at this point I'm using mod_rewrite [P] to proxy the requests to the app server rather than using ProxyPass as we have many rewrites in the conf. I've googled around and have seen that others have observed similar scenarios when using this setup in Apache 2.0 but have not seen anything specific about a resolution or path to resolution. Your help gratefully appreciated. Kind regards, Cris Cristian Pini Foresite Business Solutions Ltd Tel: 020 8540 0040 Direct: 020 8545 6813 http://www.fsite.com This message is for the named person's use only. It may contain confidential, proprietary or legally privileged information. If you receive this message in error, please notify the sender urgently and then immediately delete the message and any copies of it from your system. Please also immediately destroy any hardcopies of the message. The sender's company reserves the right to monitor all e-mail communications through their networks. - The official User-To-User support forum of the Apache HTTP Server Project. See URL:http://httpd.apache.org/userslist.html for more info. To unsubscribe, e-mail: users-unsubscr...@httpd.apache.org from the digest: users-digest-unsubscr...@httpd.apache.org For additional commands, e-mail: users-h...@httpd.apache.org
RE: RE: [us...@httpd] mod_proxy issue - intermittent 502 response
Thx for taking the time to read the post. You're right in that it's difficult to determine whether Apache is the problem, however, there's nothing sitting between the proxy and the app server and the only things that are running on the app server are apache (mod_perl) and sendmail. Having reviewed the access and error log on the proxy I can see an entry for a request that subsequently fails, however, neither the access or error logs on the app server have an entry for the request. This suggests that the request is never reaching the app server but as there's only one hop between them I'm struggling to understand what is happening to the request from the proxy. Rgds, Cris -Original Message- From: Boyle Owen [mailto:owen.bo...@six-group.com] Sent: 27 November 2009 09:17 To: users@httpd.apache.org Subject: RE: [us...@httpd] mod_proxy issue - intermittent 502 response 502 is bad gateway, which means that apache and the back-end server have got into a protocol argument. Usually this is due to a bad response from the back-end (as your log entries indicate). Why do you think apache is the problem? Rgds, Owen Boyle Disclaimer: Any disclaimer attached to this message may be ignored. From: Cristian Pini [mailto:cris.p...@fsite.com] Sent: Thursday, November 26, 2009 6:19 PM To: users@httpd.apache.org Subject: [us...@httpd] mod_proxy issue - intermittent 502 response Hi, I'm running Apache/2.0.52 as a reverse proxy on a RHE4 box, the backend app server is on a separate machine again RHE4, running Apache/2.0.52 and mod_perl 1.99_16. There are intermittent 502 responses being generated by the proxy although a page refresh generally resolves the issue, we are trying to get a configuration of 2 RP boxes in front of 3 mod_perl app servers into production but will need to understand / resolve the issue of these intermittent 502 responses first. [Thu Nov 26 15:35:09 2009] [error] [client 88.96.233.45] proxy: error reading status line from remote server xxx.xx.co.uk, referer: http://xxx..co.uk/mens/casual/casual/71/brand-/all-/start- [Thu Nov 26 15:35:09 2009] [error] [client 88.96.233.45] proxy: Error reading from remote server returned by /mens/smart/smart/70/brand-/all-/start-, referer: http://.xxx.co.uk/mens/casual/casual/71/brand-/all-/start- Can someone shed further light on what the problem is and how to resolve it pls, I'm happy to send virtual host confs if someone wishes to dig little deeper. Note at this point I'm using mod_rewrite [P] to proxy the requests to the app server rather than using ProxyPass as we have many rewrites in the conf. I've googled around and have seen that others have observed similar scenarios when using this setup in Apache 2.0 but have not seen anything specific about a resolution or path to resolution. Your help gratefully appreciated. Kind regards, Cris Cristian Pini Foresite Business Solutions Ltd Tel: 020 8540 0040 Direct: 020 8545 6813 http://www.fsite.com This message is for the named person's use only. It may contain confidential, proprietary or legally privileged information. If you receive this message in error, please notify the sender urgently and then immediately delete the message and any copies of it from your system. Please also immediately destroy any hardcopies of the message. The sender's company reserves the right to monitor all e-mail communications through their networks. - The official User-To-User support forum of the Apache HTTP Server Project. See URL:http://httpd.apache.org/userslist.html for more info. To unsubscribe, e-mail: users-unsubscr...@httpd.apache.org from the digest: users-digest-unsubscr...@httpd.apache.org For additional commands, e-mail: users-h...@httpd.apache.org - The official User-To-User support forum of the Apache HTTP Server Project. See URL:http://httpd.apache.org/userslist.html for more info. To unsubscribe, e-mail: users-unsubscr...@httpd.apache.org from the digest: users-digest-unsubscr...@httpd.apache.org For additional commands, e-mail: users-h...@httpd.apache.org
Re: RE: [us...@httpd] mod_proxy issue - intermittent 502 response
On Fri, Nov 27, 2009 at 9:52 AM, Cristian Pini cris.p...@fsite.com wrote: Thx for taking the time to read the post. You're right in that it's difficult to determine whether Apache is the problem, however, there's nothing sitting between the proxy and the app server and the only things that are running on the app server are apache (mod_perl) and sendmail. Having reviewed the access and error log on the proxy I can see an entry for a request that subsequently fails, however, neither the access or error logs on the app server have an entry for the request. This suggests that the request is never reaching the app server but as there's only one hop between them I'm struggling to understand what is happening to the request from the proxy. Rgds, Cris The 502 error basically says that the proxy couldn't connect to the backend or that the backend responded with something that it couldn't understand. Examine your network, your backend app and tcpdump the entire exchange. It is unlikely to have much to do with the proxy, which is why googling for a solution to your proxy errors did not return anything of note - this is almost always either the backend not coping, or the network not coping. Cheers Tom
Re: RE: [us...@httpd] mod_proxy issue - intermittent 502 response
Make sure there is no firewall rules blocking it. Zach - The official User-To-User support forum of the Apache HTTP Server Project. See URL:http://httpd.apache.org/userslist.html for more info. To unsubscribe, e-mail: users-unsubscr...@httpd.apache.org from the digest: users-digest-unsubscr...@httpd.apache.org For additional commands, e-mail: users-h...@httpd.apache.org
RE: [us...@httpd] mod_proxy issue - intermittent 502 response
On Today at 9:52am, CP=Cristian Pini cris.p...@fsite.com wrote: CP Thx for taking the time to read the post. CP Hi, Have you looked at Protocol Adjustments at: http://httpd.apache.org/docs/2.2/mod/mod_proxy.html#envsettings Those settings recently helped me get rid of intermittent 502 errors. Hope that helps, CP CP You're right in that it's difficult to determine whether Apache is the CP problem, however, there's nothing sitting between the proxy and the CP app server and the only things that are running on the app server are CP apache (mod_perl) and sendmail. CP CP Having reviewed the access and error log on the proxy I can see an CP entry for a request that subsequently fails, however, neither the CP access or error logs on the app server have an entry for the request. CP This suggests that the request is never reaching the app server but as CP there's only one hop between them I'm struggling to understand what is CP happening to the request from the proxy. CP CP Rgds, CP CP Cris CP -- Haroon Rafique haroon.rafi...@utoronto.ca - The official User-To-User support forum of the Apache HTTP Server Project. See URL:http://httpd.apache.org/userslist.html for more info. To unsubscribe, e-mail: users-unsubscr...@httpd.apache.org from the digest: users-digest-unsubscr...@httpd.apache.org For additional commands, e-mail: users-h...@httpd.apache.org
