mod_cluster cannot find the node

[sewatech]

Hi all,

I'm using httpd 2.2.26 with WildFly 8.1 on the same MacOS X machine. I can bind my WildFly instance to the httpd with the :add-proxy CLI operation, but httpd+mod_cluster is not able to discover the instance.

The WildFly instance is started on standalone mode, with the default standalone-ha.xml configuration. The modcluster subsystem configuration is :

  <subsystem xmlns="urn:jboss:domain:modcluster:1.2">
    <mod-cluster-config advertise-socket="modcluster" connector="ajp">
      <dynamic-load-provider>
        <load-metric type="cpu"/>
      </dynamic-load-provider>
    </mod-cluster-config>
  </subsystem>

With the advertise socket binding :

        <socket-binding name="modcluster" port="0" multicast-address="224.0.1.105" multicast-port="23364"/>

On the httpd side, the mod_cluster is configuration is :

Listen 192.168.1.38:6666
<VirtualHost 192.168.1.38:6666>

  <Location />
    Order deny,allow
    Deny from all
    Allow from 192.168.1
  </Location>

  KeepAliveTimeout 60
  MaxKeepAliveRequests 0
  
  ManagerBalancerName mycluster
  ServerAdvertise On
  AdvertiseFrequency 5  
  EnableMCPMReceive
  
</VirtualHost>

As suggested in the FAQ, I tried the Advertize test class which seems to work fine. Here is the answer :

received from /192.168.1.38:23364
received: HTTP/1.0 200 OK
Date: Thu, 10 Jul 2014 22:23:58 GMT
Sequence: 5
Digest: f8965681c8e3665333ac5c4a836452ce
Server: c95fbde6-91d6-4405-837d-b381933accc8
X-Manager-Address: 192.168.1.38:6666
X-Manager-Url: /c95fbde6-91d6-4405-837d-b381933accc8
X-Manager-Protocol: http
X-Manager-Host: mbpi7ha

I also added "AllowDisplay On" in the httpd config, and now, the cluster-manager shows the followinf data :

start of "httpd.conf" configuration
mod_proxy_cluster.c: OK
mod_sharedmem.c: OK
Protocol supported: http AJP https
mod_advertise.c: OK
Server: 127.0.0.1 
Server: mbpi7ha VirtualHost: 192.168.1.38:6666 Advertising on Group 224.0.1.105 Port 23364 for http://192.168.1.38:6666 every 5 seconds
end of "httpd.conf" configuration

And, of course, I don't see any error log, neither in httpd's error_log, nor in wildfly's server.log.

What can be wrong in my config ? What could look at ?

Alexis

[winfinit]

Alexis,

since it is on the same machine, you can't bind to the same socket, and that is probably because reuse of address is not set (SO_REUSEADDR). I don't know how to do that in jboss/java, however i looked briefly at mod_advertise, and i see that SO_REUSEADDR is set, so theoretically if you would start jboss first, let it bind to that socket, then start http, that should do the trick.

-roman

[sewatech]

Thanks for your help, Roman.

I think that the Advertize test class is the proof that httpd / mod_cluster and a Java instance can share the same multicast socket.

My problem was simplier and really dumb. I had to specify an IP binding to WildFly, for example :

bin/standalone.sh -b 0.0.0.0 -c standalone-ha.xml

Now mod_cluster and WildFly can discover each other.

Alexis