You are viewing a plain text version of this content. The canonical link for it is here.

Posted to users@httpd.apache.org by Fran Boon <fr...@gmail.com> on 2011/02/18 13:41:10 UTC

[users@httpd] proxy:ajp 'client denied by server configuration' when too many simultaneous requests happen

httpd error log:
client denied by server configuration:
proxy:ajp://localhost:8009/geoserver/gwc/service/wms

This happens under 'high' load only (pages usually display
fine...there's no specific bad URL here).

httpd snippet:
ProxyPreserveHost on
RewriteRule ^/geoserver/(.*)$ ajp://localhost:8009/geoserver/$1 [P]
ProxyPassReverse /geoserver ajp://localhost:8009/geoserver/

<LocationMatch "^(/[\w_]*/geoserver/.*)">
    Order Allow,Deny
    Allow from all
  </LocationMatch>

I have tried this without any apparent difference:
<Proxy ajp://localhost:8009>
    ProxySet keepalive=On timeout=15 ttl=60
</Proxy>

Happens even with 'Allow from all' in proxy.conf (in fact nothing in
that file makes any difference, presumably as it only affects Forward
proxies.

Back-end is GeoServer in Tomcat 6 (exactly same thing happened with
5.5) on Debian Squeeze 64-bit & current Sun JVM.
Nothing in the logs at the back-end, though, seems to be a problem
with the Connector.
Same thing whether or not using the 'APR based Apache Tomcat Native
library 1.1.20' or not.
I tried putting in a connectionTimeout into server.xml, but it makes
no difference:
<Connector port="8009" protocol="AJP/1.3" redirectPort="8443"
connectionTimeout="60000" />

Only web posts I've seen are the on/off conditions rather than erratic ones.

Many thanks, for any suggestions :)

Fran.

---------------------------------------------------------------------
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-unsubscribe@httpd.apache.org
   "   from the digest: users-digest-unsubscribe@httpd.apache.org
For additional commands, e-mail: users-help@httpd.apache.org

Re: proxy:ajp 'client denied by server configuration' when too many simultaneous requests happen

Posted by Filip Hanik - Dev Lists <de...@hanik.com>.

On 02/18/2011 02:42 PM, Fran Boon wrote:
> On 18 February 2011 20:19, Filip Hanik - Dev Lists<de...@hanik.com>  wrote:
>    
>> Simplest to try first is the disablereuse flag
>> http://httpd.apache.org/docs/2.2/mod/mod_proxy.html
>> disablereuse On
>> and if that solves the problem, you know that the problem with not enough
>> threads on tomcat.
>> (Could be from stale connections that are still holding a thread)
>>      
> Awesome - that makes it at least 10x more reliable!
> Still not perfect, but a massive improvement.
>    
Yes, it is also useful if you have more web servers than you have 
application servers.
> Any more suggestions on what I can do to clear the last errors&
> generally how to approach this configuration?
>    
What errors? I'm not sure what you are referring too here?
Since you've made changes to your environment, you may want to post more 
detail on what is going on now.
> (Apache&  Tomcat on the same physical server. Load isn't terribly high
> right now, but I'd like it to be able to scale. There is 2Gb RAM
> available (although this is shared with PostgreSQL which is tuned to
> think it has 1024 available for it)
>    
If they are on the same servers, I would leave the "disablereuse On" as 
the cost of a connection establishment is not as high as it would be 
over a network.
Plan to scale out, meaning, as one box gets high in utilization, you 
should be able to add another box with another httpd/tomcat combo to 
balance your load.
It requires some sort of load balancer in front of your web servers. 
(for software, I would look into http://haproxy.1wt.eu/)

If your database gets saturated, you may want to look into data caching 
solutions, to lower the number of trips to the database. there are 
plenty of such solutions out there. In the extreme case, you'd get rid 
of the database and move to a distributed NoSQL solution.

best
Filip
> Many thanks :)
> Fran.
>
>    
>> Filip
>>
>> On 02/18/2011 12:24 PM, Fran Boon wrote:
>>      
>>> httpd error log:
>>> client denied by server configuration:
>>> proxy:ajp://localhost:8009/geoserver/gwc/service/wms
>>>
>>> This happens under 'high' load only: 1st few requests of a batch are
>>> answered but then they start dying - there are no bad URLs here.
>>>
>>> httpd snippet:
>>> ProxyPreserveHost on
>>> RewriteRule ^/geoserver/(.*)$ ajp://localhost:8009/geoserver/$1 [P]
>>> ProxyPassReverse /geoserver ajp://localhost:8009/geoserver/
>>>
>>> <LocationMatch "^(/[\w_]*/geoserver/.*)">
>>>     Order Allow,Deny
>>>     Allow from all
>>>   </LocationMatch>
>>>
>>> I have tried these configuration options without any apparent difference:
>>> <Proxy ajp://localhost:8009>
>>>     ProxySet keepalive=On timeout=15 ttl=60
>>> </Proxy>
>>>
>>> Happens even with 'Allow from all' in proxy.conf (in fact nothing in
>>> that file makes any difference, presumably as it only affects Forward
>>> proxies.
>>>
>>> I have tried with both the default prefork MPM&    also the worker MPM.
>>>
>>> Back-end is GeoServer in Tomcat 6 (exactly same thing happened with
>>> 5.5) on Debian Squeeze 64-bit&    current Sun JVM.
>>> Nothing in the logs at the back-end, though, seems to be a problem
>>> with the Connector.
>>> Same thing whether or not using the 'APR based Apache Tomcat Native
>>> library 1.1.20' or not.
>>> I tried putting in a connectionTimeout into server.xml, but it makes
>>> no difference:
>>> <Connector port="8009" protocol="AJP/1.3" redirectPort="8443"
>>> connectionTimeout="60000" />
>>>
>>> Same with setting the minSpareThreads="32" maxThreads="256"
>>> to match those in apache.conf
>>> <IfModule mpm_worker_module>
>>>      StartServers          2
>>>      MaxClients          256
>>>      MinSpareThreads      32
>>>      MaxSpareThreads     128
>>>      ThreadsPerChild      32
>>>      MaxRequestsPerChild 1024
>>> </IfModule>
>>>
>>> None of these tuning options seem to make much difference.
>>>
>>> Only web posts I've seen are the on/off conditions rather than erratic
>>> ones.
>>>
>>> Many thanks, for any suggestions :)
>>>
>>> Fran.
>>>
>>> ---------------------------------------------------------------------
>>> To unsubscribe, e-mail: users-unsubscribe@tomcat.apache.org
>>> For additional commands, e-mail: users-help@tomcat.apache.org
>>>
>>>
>>>
>>>        
>>
>> ---------------------------------------------------------------------
>> To unsubscribe, e-mail: users-unsubscribe@tomcat.apache.org
>> For additional commands, e-mail: users-help@tomcat.apache.org
>>
>>
>>      
> ---------------------------------------------------------------------
> To unsubscribe, e-mail: users-unsubscribe@tomcat.apache.org
> For additional commands, e-mail: users-help@tomcat.apache.org
>
>
>    


---------------------------------------------------------------------
To unsubscribe, e-mail: users-unsubscribe@tomcat.apache.org
For additional commands, e-mail: users-help@tomcat.apache.org