11:18 a.m.
On Mon, May 2, 2016 at 7:32 PM, John Mazzitelli <mazz(a)redhat.com> wrote:
> The question is likely for Mazz, but I wanted to check how we
will
support the WF domain mode.
>
> As far as I understand, we are now able to run the agent in the host
> controller but wanted to know a bit more on how we expect the setup to be
> (one agent on the host controller for the whole domain ?)
<TL;DR>
I can run an agent in a host controller, but my main question is: What
special functionality are these agents supposed to provide by having them
run in the DC or HC (as opposed to running in all the standalone servers?)
</TL;DR>
Right now, I have the agent at least able to run in a host controller.
Each machine where you run your app servers has one host controller on
them. Additionally, somewhere in your network, there is a single host
controller that is configured to run as the domain controller (i.e. a
"domain controller" is just a specially configured host controller - there
is only one DC per domain).
We can run the agent today in a host controller (note: I have no agent
configuration that tells the agent how to monitor that HC itself - there
are not the same subsystems running in a HC than what you see running in a
standalone WildFly server).
Do we want to run the agent only in the domain controller? Or do we want
to run one agent in each host controller? I suspect we want to do the
latter, not the former, simply because it seems to follow the typical way
agents are run (one per machine). However, I'm still not clear what it is
people want these agents running in a DC or HC to do. What special
functionality are these agents supposed to provide by having them run in
the DC or HC (as opposed to running in all the standalone servers?)
We need to be able to "visualize" server groups and domains --> that
topology needs to fill in the inventory
We'll want to be able to execute operations on a domain or server group,
like deploy an application (without re-implementing the logic for failed
deployment on 1 or more servers for instance)
If the domain/host controller collects all metrics for all servers or if
each server reports itself is more of an implementation detail. Also I
understand that have all data going through the domain controller would
create a bottleneck, one per host seems more suitable on first thoughts.
Thomas
A different approach to consider is that we can have the host controllers
inject agents into the WildFly servers they spawn (so we can then monitor
each of the standalone servers that are started by the host controller
since each standalone server can get an agents installed via the HC). I am
not sure if HCs can actually push out module subsystem extensions like they
can deployments - we'd have to ask wildfly-dev. But it would be cool to add
the agent subsystem to the domain's profiles so when a HC runs a WildFly
server it can not only push out the deployments but also the agent
subsystem extension.
> Also I wanted to ask if older versions of the app server could be
supported
> or only WF 10 ? (in particular in the context of EAP7/EAP6 support)
I have not tried to run this in a WF9 instance - but alot of this is
fairly new in the WF codebase. There was a time when custom subsystem
extensions could NOT run in these host controllers - wildfly devs had to
add some stuff to get that to work. I suspect (though I do not know for
sure) that it won't work on EAP6.
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