Wildfly 9.0.0.CR1 + modcluster without advertising - using "proxies" not works

[salamont]

We are currently testing to move from Wildfly 8.2.0 to Wildfly 9.0.0.CR1 (or CR2 built from snapshot). The system is a cluster using mod_cluster and is running on VPS what in fact prevents it from using multicast.

On 8.2.0 we have been using the following configuration of the modcluster that works well:

          <mod-cluster-config proxy-list="1.2.3.4:10001,1.2.3.5:10001" advertise="false" connector="ajp">

              <dynamic-load-provider>

                  <load-metric type="cpu"/>

              </dynamic-load-provider>

          </mod-cluster-config>

Unfortunately, on 9.0.0 proxy-list was deprecated and the start of the server will finish with an error. There is a terrible lack of documentation, however after a couple of tries I have discovered that proxy-list was replaced with proxies that are a list of outbound-socket-bindings. Hence, the configuration looks like the following:

          <mod-cluster-config proxies="mc-prox1 mc-prox2" advertise="false" connector="ajp">

              <dynamic-load-provider>

                  <load-metric type="cpu"/>

              </dynamic-load-provider>

          </mod-cluster-config>

And the following should be added into the appropriate socket-binding-group (full-ha in my case):

        <outbound-socket-binding name="mc-prox1">

            <remote-destination host="1.2.3.4" port="10001"/>

        </outbound-socket-binding>

        <outbound-socket-binding name="mc-prox2">

            <remote-destination host="1.2.3.5" port="10001"/>

        </outbound-socket-binding>

So far so good. After this, the httpd cluster starts registering the nodes. However I am getting errors from load balancer. When I look into /mod_cluster-manager, I see a couple of **Node REMOVED** lines and there are also many many errors like:

    ERROR [org.jboss.modcluster] (UndertowEventHandlerAdapter - 1) MODCLUSTER000042: Error MEM sending STATUS command to node1/1.2.3.4:10001, configuration will be reset: MEM: Can't read node

In the log of mod_cluster there are the equivalent warnings:

manager_handler STATUS error: MEM: Can't read node

As far as I understand, the problem is that although wildfly/modcluster is able to connect to httpd/mod_cluster, it does not work the other way. Unfortunately, even after an extensive effort I am stuck.

Could someone help with setting mod_cluster for Wildfly 9.0.0 without advertising? Thanks a lot.

[rhusar]

Thanks for the report, looking into it.

[rhusar]

Alright, I have given this a try and I cannot reproduce the problem. Originally I was worried that the proxies=".." functionality is broken since its new, but it works fine. I ll try to update the documentation too.

The problem you are hitting is with the native part. What version are you using? We have just released binaries for 1.3.1.Final, please give it a try but otherwise restarting apache (maybe even machine) and cleaning the modcluster work files should do the job too and hopefully that issue is fixed in the latest version too.

[salamont]

Thanks for the replies. After a couple of weeks I got back to the problem and found the solution. The problem was - of course - in configuration and had nothing in common with the particular version of Wildfly. Mode specifically:

There were three nodes in the domain and three servers in each node. All nodes were launched with the following property:

-Djboss.node.name=nodeX 

...where nodeX is the name of a particular node. However, it meant that all three servers in the node get the same name, which is exactly what confused the load balancer. As soon as I have removed this property, everything started to work.

[rhusar]

Right, node names need to be unique.