Re: Apache losing its connection from Tomcat in few minutes

[Dr James Smith <js5@xxxxxxxxxxxx>]

You don't give enough information about the setup to solve any of your problems really.

Are the apache/tomcat/cms on the same box or different

We have seen big problems with mod_jk when there are firewalls involved (so much so we don't use it any more but use mod_proxy instead) - connections are severed by the firewall - you need to look up "tcp keep alive" settings for your connections - but even then that doesn't help - mod_jk doesn't handle this situation well... (ditto nginx, mod_fcgi etc none of them really handle any form of flakyness when it comes to network well)

And also mod_proxy is a lot easier to set up that mod_jk - and the slight overhead of not-compressing the apache headers/possibly renogatiting connections will not be significant if your CMS is take 10 seconds to return - which is already about 9 seconds to long anyway!

Other things - shared file systems are generally a bad idea in a web environment - (esp NFS) as overhead/stability issues can be critical in high volume webservers..

Now for mod_proxy for what you want to do!

ProxyPass /files !
ProxyPass / http://tomcatserver:port/
ProxyPassReverse / http://tomcatserver:port/

Caching probably isn't an issue now - or shouldn't be... as your static content is being server via Apache directly - but I would read up on web optimisation in general:

• How to minimize number of resources in a web page;
• Setting cache control, etag headers etc to stop the client re-requesting resources;
  
• Using mod_deflate correctly [ Note turn off deflate on tomcat - DO NOT GET IT TO COMPRESS CONTENT!]
  
• Look at avoiding redirects etc if possible....

Only when you have resolved all those issues then will you want to look at setting up "dumb server" caching - because unless you understand it well it can cause more problems that it solves! and anyway getting the cache headers right will make it easier! Get servers closer to the user caching content is always the best way!!!

James

On 04/09/2016 09:48, Jayaram Ponnusamy wrote:

Dear All,

In our Environment we are using Apache HTTP and Tomcat as AppServer on J2EE based CMS System. and We are using AJP 1.3 connector (Apache HTTPD, Tomcat, CMS are in seperate systems)

Normally accessing the sites & pages through WebServer URL is very slow compare to use Tomcat URL. 

The Wired behavior is Apache HTTP is losing connection with Tomcat in few minutes (eg 10-15minutes) then we have to hit the WebServer URL continuously or reboot httpd to resolve this issue.

In the MOD_JK Logs we could see below errors.

[Sun Sep 04 01:17:34 2016][7945:488081152] [info] ajp_connection_tcp_get_message::jk_ajp_common.c (1150): (prd_live_svr) can't receive the response header message from tomcat, network problems or tomcat (10.100.116.31:9009) is down (errno=110)

[Sun Sep 04 01:17:34 2016][7945:488081152] [error] ajp_get_reply::jk_ajp_common.c (1962): (prd_live_svr) Tomcat is down or refused connection. No response has been sent to the client (yet)

[Sun Sep 04 01:17:34 2016][7945:488081152] [info] ajp_service::jk_ajp_common.c (2447): (prd_live_svr) sending request to tomcat failed (recoverable),  (attempt=1)

[Sun Sep 04 03:35:02 2016]prd_live_svr cmsliv.com 32.624815

[Sun Sep 04 03:36:02 2016][13358:488081152] [info] ajp_process_callback::jk_ajp_common.c (1788): Writing to client aborted or client network problems

[Sun Sep 04 03:36:02 2016][13358:488081152] [info] ajp_service::jk_ajp_common.c (2447): (prd_live_svr) sending request to tomcat failed (unrecoverable), because of client write error (attempt=1)

[Sun Sep 04 03:36:02 2016]prd_live_svr cmsliv.com 39.879029

[Sun Sep 04 03:36:02 2016][13358:488081152] [info] jk_handler::mod_jk.c (2608): Aborting connection for worker=prd_live_svr

Errors Log:

[Sun Sep 04 09:32:00 2016] [debug] proxy_util.c(1921): proxy: worker proxy:reverse already initialized

[Sun Sep 04 09:32:00 2016] [debug] proxy_util.c(2017): proxy: initialized single connection worker 0 in child 24423 for (*)

[Sun Sep 04 09:54:24 2016] [debug] proxy_util.c(1901): proxy: grabbed scoreboard slot 0 in child 24513 for worker proxy:reverse

[Sun Sep 04 09:54:24 2016] [debug] proxy_util.c(1921): proxy: worker proxy:reverse already initialized

[Sun Sep 04 09:54:24 2016] [debug] proxy_util.c(2017): proxy: initialized single connection worker 0 in child 24513 for (*)

[Sun Sep 04 09:54:29 2016] [debug] proxy_util.c(1901): proxy: grabbed scoreboard slot 0 in child 24514 for worker proxy:reverse

[Sun Sep 04 09:54:29 2016] [debug] proxy_util.c(1921): proxy: worker proxy:reverse already initialized

[Sun Sep 04 09:54:29 2016] [debug] proxy_util.c(2017): proxy: initialized single connection worker 0 in child 24514 for (*)

[Sun Sep 04 10:01:48 2016] [debug] proxy_util.c(1901): proxy: grabbed scoreboard slot 0 in child 24563 for worker proxy:reverse

[Sun Sep 04 10:01:48 2016] [debug] proxy_util.c(1921): proxy: worker proxy:reverse already initialized

[Sun Sep 04 10:01:48 2016] [debug] proxy_util.c(2017): proxy: initialized single connection worker 0 in child 24563 for (*)

Configurations:

worker.list=prd_live_svr

worker.prd_live_svr.type=ajp13

worker.prd_live_svr.host=cmsliv

worker.prd_live_svr.port=9009

live.conf

<VirtualHost *:80>

ServerAlias cmsliv

    ErrorLog logs/live/http_error.log

    RewriteLog logs/live/http_rewrite.log

    CustomLog "|/opt/apps/apache/bin/rotatelogs -f  /opt/apps/apache/logs/live/http_access.log.%Y.%m.%d 86400 +60" imi

    RewriteEngine on

RewriteCond %{REMOTE_ADDR} !^10\.100\.116\.31$

DocumentRoot /opt/apps/opentext

RewriteRule ^/+$ /sites/  [R,L]

<IfModule rewrite_module>

Options +FollowSymlinks

RewriteEngine On

RewriteOptions Inherit 

#RewriteLogLevel 9

RewriteLog logs/rewrite.log

</IfModule>

JkMount   /*        prd_live_svr

</VirtualHost>

httpd.conf:

NameVirtualHost *:80

Include conf/qu/live.conf

Timeout 300

KeepAlive On

MaxKeepAliveRequests 100

KeepAliveTimeout 15

<IfModule worker.c>

StartServers 6 

MaxClients 230 

MinSpareThreads 75 

MaxSpareThreads 150

ThreadsPerChild 25

MaxRequestsPerChild 0

</IfModule>

Kindly please help to resolve this issue.

-- 

Thanks & Regards,

Jayaram Ponnusamy 

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