[jboss-as7-dev] :installed-drivers-list on managed server or SG?

[Brian Stansberry]

On 6/8/11 3:23 AM, Heiko W.Rupp wrote:
> Brian,
>
>>> actually with picking a random host within a server group after previously having uploaded
>>> and deployed the driver jar to the server group.
> [..]
>>> Wouldn't it make more sense to put :installed-drivers-list on server-group level?
>>>
>>
>
>> The server group resource knows nothing about the details of the
>> profile, i.e. what operations its subsystems expose on the servers, it
>> just knows that the servers are running a profile named "x".
>
> Shouldn't that be sort of the same things? I mean if I can :add a jdbc driver to
> a server-group, which in turn installs it on all the managed servers, shouldn't
> then there be a :list as its counterpart?
>
>> I could see a generic operation on the server-group resource that
>> amounts to "execute operation X on all servers in the group and provide
>> an aggregate response."
>
>
> Hm.  That would for sure be helpful.
>

Another variant could be to "execute operation X on any random running 
server in the group". This is for the case where the result is expected 
to be the same from all servers.

> The other thing that I am concerned with is consistency. My understanding is so far
> that a server group consists of (almost) identical managed servers. Of course IP,
> port mapping and perhaps jvm characteristics are the same.
> This means to me, that when I deploy something to a server group, this thing
> ends up in every managed AS  and the other way around: everything that is deployed
> to a managed AS can be found on all managed AS of the respective server group.
>
> This also implies that for deployments, the server-group is the point of interaction and
> not a single host.
>

Depends on the interaction. A lot of things will be consistent across 
all servers; other things may not be, e.g. metrics. The DC isn't going 
to have in memory details about the deployment that are ony discovered 
when the deployment passes through the deployment processor chain, as 
that only happens on the servers. So even for the stuff that's 
consistent across servers, the DC is going to have to go to a server to 
find out the information.

This is why I'm thinking in terms of generic operations that can be 
offered at the server group level but which handle for the end user the 
task of calling to the servers.

>    Heiko
>


-- 
Brian Stansberry
Principal Software Engineer
JBoss by Red Hat