Hi Adrián,
The question is probably more suitable on a rpm list.
We don't distribute our jar's with rpm but I appreciate your dillema.
I don't personnally think that for such complex applications, rpm is the right way to upgrade with. I see rpm has a way to distribute "core" stuff, and not suitable for distributing weird and wonderfull applications that requires restarts and database upgrades etc. There is application servers and frameworks that is better suited for this type of thing and that sits on a logically higher level. JBoss, Wesphere and I think even tomcat has some basic stuff build in.
Regards
-----Original Message-----
From: spacewalk-list-bounces redhat com
[mailto:spacewalk-list-bounces redhat com] On Behalf Of Adrián Márques
Sent: 06 October 2008 18:45
To: spacewalk-list redhat com
Subject: [Spacewalk-list] How to update running applications?
Dear all,
I'm having a difficult time in finding the correct forum to
pose this question since I guess it's part spacewalk, part
RPM, part basic aplication design.
Being an RPM end-user for years I had always assumed that
updating running apps was a piece of cake with RPM. After
all, I always did it and the most I got were occasional
messages such as "Firefox restart required", never
encountering other side-effects.
However, after reading through the RPM guide, getting my
hands dirty trying to package an app, scouring the internet
for info and asking around in the RPM mailing list, I'm still
not sure how to write my RPM so updating won't be an issue.
The scenario is the following: I'd like to use spacewalk to
distribute a custom desktop app. Hence, it's unavoidable that
some users will be working at the time of an update. So far
I've identified two problems with this, 1) If I have to
modify the app's database schema as part of the update, the
running app might break down if it's not aware of the change
2) This happens to be a java app, so in case a jar gets
updated a class might get loaded that is not compatible with
those already loaded by the running app.
I understand that what I've explained so far might be outside
of the scope of the subjects treated in this mailing list, if
so, please just treat it as a detailed background problem description.
What I would like to know from you guys is whether you've had
any problems when updating apps through Satellite/Spacewalk
due to them being running at the time or what precautions (if
any) you take when doing so.
Finally, I suppose that as a last resort I could hack the
spacewalk client to only download updates and not install
them until it is told to do so from the command line. Is this
already possible? If not, where's the place to start with
hacking this?
I thank you all for your time and attention. It'd be amazing
if you had any comments regarding my background issue, but
I'll be more than satisfied and grateful if you could just
provide any feedback on those questions strictly spacewalk-related.
Thanks.
Adrián.
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