Databases
StackOverflow2013
Postsdbo
POapache2 ignores MaxKeepAliveRequests, closes connections arbitrarily
 

Note that there are some explanatory texts on larger screens.

plurals
  1. POapache2 ignores MaxKeepAliveRequests, closes connections arbitrarily
    primarykey
    data
    text
    <p>We have a Tomcat front-end server that proxies to our Apache 2.2.11 app server, running on a 64-bit Fedora 2.6.21.7 EC2 2xlarge instance (AKI aki-b51cf9dc). Apache is running mod_perl and is not threaded.</p> <p>We are trying to have the connections persist for a long time between Tomcat, running on another EC2 instance, and the Apache server, while not persisting connections from outside clients coming directly into the Apache server. Our config looks like this:</p> <pre><code>Listen 80 NameVirtualHost *:80 # used for external clients &lt;VirtualHost *:80&gt; ServerName xxx.yyy.com ServerAlias *.yyy.com DocumentRoot "/var/www/html" KeepAlive Off &lt;/VirtualHost&gt; # used from tomcat server on local network &lt;VirtualHost *:80&gt; ServerName ip-&lt;Apache-server-local-IP&gt;.ec2.internal KeepAlive On KeepAliveTimeout 3600 MaxKeepAliveRequests 0 DocumentRoot "/var/www/html" &lt;/VirtualHost&gt; TimeOut 60 MinSpareServers 20 MaxSpareServers 30 StartServers 20 MaxClients 60 GracefulShutdownTimeout 90 </code></pre> <p>We've tried all sorts of values for MaxKeepAliveRequests and KeepAliveTimeout, and the server definitely maintains a connection for a while with Tomcat, but it always closes it within a matter of seconds, when only some tens of requests have been processed. It may be significant that I've never seen a process maintain 100 or more connections on a socket while observing using mod_status.</p> <p>There are never any persistent connections with the non-Tomcat clients, so we know that there is some difference going on there and the VirtualHost config is definitely being applied in both cases.</p> <p>I should mention that the requests from Tomcat are all POSTs while the others are a mixture of POSTs and GETs.</p> <p>When I look a the traffic on a given port with tcpdump I can clearly see a number of POSTs being processed correctly and then at some point after returning a good reply (200, data looks fine) the Apache server immediately closes the connection, sending a FIN to Tomcat. This happens in cases where there is absolutely no difference between the last and second-to-last requests or replies other than minor data like the real client's IP, so there's no indication of the server barfing while processing a request. And of course there's nothing suspicious in the error logs and the httpd processes themselves are not dying.</p> <p>From netstat we can see the connections to the Tomcat server being held open for some seconds, but cycling pretty quickly through the range of remote ports, verifying what we see elsewhere. It's almost like Apache is trying to fairly allocate connections to prevent the persistent ones from starving the others--but it wouldn't do that, would it?!</p> <p>I'd like nothing more than to be told that we're doing something dumb here! Please, please tell me I'm an idiot, or at least near-sighted...</p>
    singulars
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. PTQuestion
    1. This table or related slice is empty.
    1. USPeter Jeffe
    plurals
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. PO
      singulars
      1. PTAnswer
    2. PO
      singulars
      1. PTAnswer
    1. VO
      singulars
      1. POapache2 ignores MaxKeepAliveRequests, closes connections arbitrarily
      1. This table or related slice is empty.
      1. VTUpMod
    1. COI'd suggest you post this on serverfault.com as well for a better response.
      singulars
      1. POapache2 ignores MaxKeepAliveRequests, closes connections arbitrarily
      1. USJoseK
    2. COYeah, I did. It's had 8 views there and not even a comment, go figure.
      singulars
      1. POapache2 ignores MaxKeepAliveRequests, closes connections arbitrarily
      1. USPeter Jeffe
 

Querying!

 
Guidance
A row detail

Detail views are divided into sections. All the information in the data section comes from columns in the selected row. The other sections display data from other, related rows.

Related data can be related in a to-one or a to-many fashion. Captions of data related in a to-many fashion link to a list view showing a filtered view of the table.

Try moving around until you find a non-empty to-many entry and click on the label to get to one. You can move back to the root by clicking on the database name in the header.

SQuiL has stopped working due to an internal error.

If you are curious you may find further information in the browser console, which is accessible through the devtools (F12).

Reload