Puppet users - Jul 2012 - subscribe is not restarting the service even though the file has changed :(

Hi All,
 
I am managing the config files of a service through puppet. This config 
file is being created through 2 separate modules and concatenated 
together.  I am trying to modify the manifest in the module that installs 
the service so that whenever this config file changes (when the portion 
that comes from the 2nd module is concatenated to it), the service should 
restart.  I tried using the notify/subscribe parameter here, but the 
service does not restart even though the content of the file gets changed.
 
However, if I use the notify parameter on the second module by associating 
it with the service created by the first module, the service gets 
restarted.  I DO NOT want to do this way because it creates a dependency 
between these two modules which otherwise have been exclusive of one 
another.  Is there some way around this? The change in the config file 
content is happening only at the portion that is being modified by the 
second module.  But still, since I have used a subscribe parameter on the 
config, I believe that irrespective of which part of the file gets 
modified, the service must restart. 
 
Does anybody have any idea if my understanding is correct or a way to work 
around this? Any help would be highly appreciated!!!
 
 
 service {"DE_${service_name}":
        enable          => true,
        ensure          => true,
        hasrestart      => true,
        hasstatus       => true,
        subscribe => 
File["${service_base_config_dir}/serverConfig.properties"]
        }
 
 

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On Thursday, July 19, 2012 4:29:53 AM UTC-5, Praveen Shivashankar
wrote:
>
> Hi All,
>  
> I am managing the config files of a service through puppet. This config 
> file is being created through 2 separate modules and concatenated 
> together.  I am trying to modify the manifest in the module that installs 
> the service so that whenever this config file changes (when the portion 
> that comes from the 2nd module is concatenated to it), the service should 
> restart.  I tried using the notify/subscribe parameter here, but the 
> service does not restart even though the content of the file gets changed.
>  
> However, if I use the notify parameter on the second module by associating 
> it with the service created by the first module, the service gets 
> restarted.  I DO NOT want to do this way because it creates a dependency 
> between these two modules which otherwise have been exclusive of one 
> another.
>

That doesn''t make sense.  You have a dependency whether you subscribe
in
one direction or notify in the opposite direction.  The two modules cannot 
be exclusive.  Moreover, they *should not* be exclusive.  It doesn''t
make
sense to manage a service and its config file independently of one another.

 
>   Is there some way around this? The change in the config file content is 
> happening only at the portion that is being modified by the second module.
> But still, since I have used a subscribe parameter on the config, I believe
> that irrespective of which part of the file gets modified, the service must
> restart. 
>  
> Does anybody have any idea if my understanding is correct or a way to work 
> around this? Any help would be highly appreciated!!!
>
Puppet subscribe / notify relationships respond to changes in the
*Puppet*resources on the precedent side (the target of the subscribe or the
source
of the notify).  It is possible -- but unwise -- to set things up so that 
those resources do not model all the properties of the physical resource 
that you want to respond to.  It sounds like that''s probably
what''s
happening here.
 
>   
>  service {"DE_${service_name}":
>         enable          => true,
>         ensure          => true,
>         hasrestart      => true,
>         hasstatus       => true,
>         subscribe => 
> File["${service_base_config_dir}/serverConfig.properties"]
>         }
>  
>
That setup will cause the service to be restarted if any of the properties 
managed via
File["${service_base_config_dir}/serverConfig.properties"] are
changed, *as
determined by that resource*.  If something else is done to the underlying 
file via another resource then the File knows nothing of it and will not 
broadcast an event.

You have left out the most important parts, which are the multiple 
declarations by which you manage file
${service_base_config_dir}/serverConfig.properties.  I can''t give you 
specific advice without understanding what you''re doing / trying to do.
In
general, however, there are multiple possible approaches:

   1. Combine the declarations managing your file into a single resource, 
   and make your service subscribe to that.  That resource might be a File, an 
   instance of a local defined type, or a resource from the Concat module, for 
   instance.
   2. Have your service subscribe to all resources managing parts of the 
   file, instead of just one.  To do that, the value assigned to its 
   ''subscribe'' property should be an array of the needed
resource references.
   3. Use ''notify'' going in the other direction, from each
resource
   managing part of the file to the service it configures.


John

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What I have done with all my service resources is I declared the start, 
stop, restart and status parameters. I''ve never had a problem with 
subscriptions and notifications. 

On Thursday, July 19, 2012 5:29:53 AM UTC-4, Praveen Shivashankar
wrote:
>
> Hi All,
>  
> I am managing the config files of a service through puppet. This config 
> file is being created through 2 separate modules and concatenated 
> together.  I am trying to modify the manifest in the module that installs 
> the service so that whenever this config file changes (when the portion 
> that comes from the 2nd module is concatenated to it), the service should 
> restart.  I tried using the notify/subscribe parameter here, but the 
> service does not restart even though the content of the file gets changed.
>  
> However, if I use the notify parameter on the second module by associating 
> it with the service created by the first module, the service gets 
> restarted.  I DO NOT want to do this way because it creates a dependency 
> between these two modules which otherwise have been exclusive of one 
> another.  Is there some way around this? The change in the config file 
> content is happening only at the portion that is being modified by the 
> second module.  But still, since I have used a subscribe parameter on the 
> config, I believe that irrespective of which part of the file gets 
> modified, the service must restart. 
>  
> Does anybody have any idea if my understanding is correct or a way to work 
> around this? Any help would be highly appreciated!!!
>  
>  
>  service {"DE_${service_name}":
>         enable          => true,
>         ensure          => true,
>         hasrestart      => true,
>         hasstatus       => true,
>         subscribe => 
> File["${service_base_config_dir}/serverConfig.properties"]
>         }
>  
>  
>
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@John,
 
Thanks a lot for the detailed reply. I do concur with the idea that they 
cannot be mutually exclusive. But for some reason the client had that 
requirement. Fortunately I was able to convince them to let go of that, and 
now I just went ahead and pass the service name as an external parameter 
and using the notify can restart the service whenever the change in config 
file happens. 

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