I am not sure you are using the terms right, surely its a bit confusing:
- domain is only about management, provisioning, etc.
- clustering is about session replication, ie. http and ejb sfsb state replicate in between the nodes so that harware failure doesn't result in an outage
- mod_cluster is an apache module that works as load balancer (mod_jk replacement) and a part of AS that registers with the load balancer automatically
So Q1 has nothing to do with clustering, and Q2 modcluster has nothing to do with domain controller.
thanks for your reply,But I know what you say about modcluster founction.
If I want to add annother slave,
in this situation I will have one domain controller and two slave with it ,how should I configure the <host name="???" xmlns="urn:jboss:domain:2.0"> in host.xml ?
that is to say "domian controller can only have one slave ?"
In Production environment, If domain controller doesn't wrok, modcluster in httpdserver can send client request to slave ? in this situation,how to realise the failover about domain controller?
(domain controller have 3 servers in 10.19.182.2, slave have 3 servers in 10.19.181.3,httpd with modcluster in 10.19.182.4)
A domain controller can have many slaves. Each slave need to have a unique name, you might set "hc1, hc2 ..." or any unique name you want.
The error during HC start is because of the secured managment connection. You need to set a management user at the domain configuration and add the passwort base64 encoded to the HC security realm. If the HC is at the same machine this is not necessary as the domain contoller will accept the local slave by default.
The user name is the specified name for the host-element, but you might override it by the domain controller configuration in the slave's host.xml.
modcluster will not sent requests to the 'slave' HC.
The slave starts one or more server instances which are responsible to handle the application load.
Domain controller, host controller and the process controller (only seen as java process) are only management instances and not handling any applicaition response.
The servers are continue handle applicaiton requests. Only the host controller will log periodical a message that there is no domain controller available.
It will reconnect to the domain if it is up again.
There is no automatic domain-controller failover mechanism implemented.
thank you very much! That's what I want