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