[jboss-as7-dev] Management Console JDK Server Example

[Brian Stansberry]

On 1/21/11 4:15 AM, Darran Lofthouse wrote:
> On 01/20/2011 08:32 PM, Brian Stansberry wrote:
>> These are valid points. Being able to run the console on a process other
>> than the DC is a plus for users who see the DC as critical
>> infrastructure where they don't want anything extraneous going on; i.e.
>> they do a lot of management via scripts and only occasionally run the
>> console.
>
> One question that came up this week was why isn't the DC also running on
> a minimal AS? I assume this has already been considered but it would
> bring some additional benefits: -
>
> - The DC becomes just another host so any instability in the DC and the
> host controller is unaffected and can restart it as required.
> - Whilst minimal services is still desirable services already provided
> within AS can be used.
>
> And also later if there was ever need to implement a more master/slave
> domain controller architecture this could be achieved with a server
> group specifically for the domain controller.
>

What you're describing is running the domain controller functionality as 
a module inside a server instead of inside a HostController.

Some problems:

1) It's more screw-upable. The process running the DC can now be tasked 
to do anything, whatever a user wants. Many, many more ways to mess up.

2) It adds another process to a minimal domain. You have to have a 
HostController to have a running, manageable domain. You don't have to 
have any running servers. With the DC inside a server, now you do.

3) Servers all are members of a server group, and other than some 
host-specific stuff like IP addresses, all members have an identical 
config. So the config for this domain controller functionality would 
either come from:

a) A profile in domain.xml that includes a "domain-controller" subsystem 
and that gets mapped to a given server-group.

b) Some new child element in domain.xml <server-group/> that configures 
the DC functionality.

Problem is, it's the domain-controller module that actually parses and 
otherwise manages domain.xml. So you have a chicken-and-egg problem at 
domain boot.

4) The DC controls a server by delegating to its HostController. So it 
would control its own server by delegating to its HC which would call 
back. Which could work but smells funny.


-- 
Brian Stansberry
Principal Software Engineer
JBoss by Red Hat