[Nix-dev] [disnix] Deactivation of services

[Sander van der Burg - EWI]

Disnix does deactivate previous services, but only the ones that are obsolete. So if your old distribution model and new distribution model contain the same service, Disnix tries to keep them intact.

In your case, I think you may have removed a machine from your infrastructure model, which has some services running that are previously deployed. Not having a machine in your infrastructure model means that this particular machine is no longer available and it is no longer known how it can be reached and what it's other relevant properties are. Therefore Disnix skips the deactivation.

If you want to properly "clean" a machine and remove it from the network, you should remove it from the infrastructure after all services have been deactivated on it. So basically you must first adapt the distribution model (not mapping services to the obsolete machine), then do a redeployment (disnix-env) to deactivate the services, and then remove it from the infrastructure model. 

I hope this makes things a bit more clear. The reason why Disnix behaves this way is to deal with networks in which machines may randomly appear or disappear. When a machine crashes, it may be possible that an upgrade cannot be performed. By skipping a non-existent machine you can "fix" the deployment of a system in a crashing network.

-----Original Message-----
From: nix-dev-bounces at cs.uu.nl on behalf of Kamil Klimkiewicz
Sent: Fri 4/15/2011 12:02 PM
To: nix-dev at cs.uu.nl
Subject: [Nix-dev] [disnix] Deactivation of services
 
Hi,

Could you guys tell me what could be the reason that disnix services
don't get deactivated, new services simply get activated w/o first
deactivating previous versions of the services (I get 'Skip deactivation
of service ...). So I'd basically want to know what condition disnix
checks when deciding to deactivate or not given service.

Thanks.

-- 
Best regards,
Kamil

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