Re: [Fwd: RE: Soft IOCs and Port Numbers]

[Pam Gurd <pamgurd@shaw.ca>]

 

Perhaps I should be more clear.  When I was at the SNS, we had multiple soft IOCs running on each of several servers.  We used the EPICS_CA_SERVER_PORT environment variable to give each one a unique port; however, this solution was, and continues to be, up to the goodwill and good management of the IOC engineer.  (I have a private message from Kay, but I should get his permission before I share it.)  I was wondering whether anyone had a more structured approach.

 

I like the idea of separating functions by IOC, having lots of IOCs.  You can get permission to reboot most of the applications that way, and leave the essential, unbootable, functions alone.

 

   Pam.


----- Original Message -----
From: Anze Zagar <anze.zagar@cosylab.com>
Date: Friday, September 24, 2010 3:00 pm
Subject: [Fwd: RE: Soft IOCs and Port Numbers]
To: Pam Gurd <pamgurd@shaw.ca>

> Hi Pam,
>
> This answer was not sent to EPICS Tech Talk but rather to me directly,
> so I'm forwarding it FYI.
>
> Cheers,
> Anze.
>
>
> -------- Forwarded Message --------
> From: Touchard Dominique <Dominique.Touchard@ganil.fr>
> To: Anze Zagar <anze.zagar@cosylab.com>
> Subject: RE: Soft IOCs and Port Numbers
> Date: Fri, 24 Sep 2010 13:45:02 +0200
>
> o) Do something with modular epics and have only one IOC application
> running, hosting all the required IOCs as modules.
>
> Hi Anze,
>
> As far as I'm concerned, for the SPIRAL2 control command
> project, we has organized our software implementation with EPICS
> modules. An application is an IOC. An equipment interface is a
> module. An IOC application controls a facility line section or
> function.
> I should say that I'm a little bit curious. On the other way,
> why do you need few IOCs on the same host? Is it really a need,
> a constraint caused by a lack of implementation method or by an
> unmanaged(able) integration process?
>
> Dominique Touchard.
>
> -----Message d'origine-----
> De : tech-talk-bounces@aps.anl.gov [mailto:tech-talk-
> bounces@aps.anl.gov] De la part de Anze Zagar
> Envoyé : vendredi 24 septembre 2010 13:02
> À : matthew.pearson@diamond.ac.uk
> Cc : tech-talk@aps.anl.gov
> Objet : RE: Soft IOCs and Port Numbers
>
> Hi Matthew,
>
> Actually the issue is not on client side. CArepeater is used for
> clientapplications to share the beacon UDP port (e.g. EDM
> screens and also
> IOCs because they can be clients to one another...). We are wondering
> here, how to host multiple soft IOCs on the same computer, possibly
> sharing the same UDP CA request port. For broadcast UDP packets
> this is
> not really an issue, because Linux UDP stack is implemented in
> such a
> way that it by default fans out the packet to all services
> running on
> that particular port. Though, I'm not convinced that this is really
> standard UDP stack behavior and that we have any guaranties it will
> still work with future versions of Linux kernel. The second
> problem is
> that at some stage ITER may also want to configure some client
> to send
> unicast requests. Then it will for certain not work on Linux
> because in
> that case only one IOC will in fact receive the request.
>
> I see a few possibilities here:
> o) Ignore the problem and assume that in ITER broadcast UDP will
> alwaysbe used and there will be no problems in future. This is
> also ok if we
> assume that at some stage they will switch to EPICS v4 where port
> sharing will no longer be an issue.
> o) Do something with modular epics and have only one IOC application
> running, hosting all the required IOCs as modules.
> o) Assign different ports to different IOCs. This will very likely
> course cause a lot of other manageability issues.
>
> Cheers,
> Anze Zagar.
>
>
>
> On Fri, 2010-09-24 at 11:22 +0100, matthew.pearson@diamond.ac.uk
> wrote:> Here at ITER, t
> > Hi Pam,
> > 
> > We use the CArepeater UDP server on our linux hosts.
> > 
> > http://www.slac.stanford.edu/comp/unix/package/rtems/epics-
> 3.14.6/base/html/CAref.html#Repeater> 
> > Is that what you need?
> > 
> > Cheers,
> > Matthew
> >
> >        
> >        
> ______________________________________________________________>         From: tech-talk-bounces@aps.anl.gov
> >         [mailto:tech-
> talk-bounces@aps.anl.gov] On Behalf Of Pam Gurd
> >         Sent: 24
> September 2010 09:18
> >         To: EPICS tech-talk
> >         Subject: Soft
> IOCs and Port Numbers
> >        
> >        
> >        
> >         hey're asking
> me about how to manage the problem of ensuring
> >         that each of
> the soft IOCs running on a host has a distinct
> >         port number.
> >        
> >         
> >        
> >         What have
> people done to solve this problem?
> >        
> >         
> >        
> >         Thanks.
> >        
> >         
> >        
> >            Pam.
> >        
> >        
> >
> >
> >
> > 
> >
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