Re: How Unix manages processes in userland

["Aaron B." <aaron%zadzmo.org@localhost>]

On Sat, 07 Dec 2013 01:26:27 +0000
Roy Marples <roy%marples.name@localhost> wrote:

> On 07/12/2013 1:08, Aaron B. wrote:
> > As a sysadmin, I often care less about the internal details, and more
> > about what a system provides. What I want to see:
> > 
> > 1) Easy to define/install a new service
> > 2) Easy to manipulate a service (enable/disable/restart/etc)
> > 3) Easy to query a service's state.
> > 
> > IMHO, #3 is the ticky part. People often assume things are 'up' or
> > 'down' and ignore the scope of all the other failures in between.
> 
> Well, from a service management perspective it's either up or down.
> It may have an intermediate state of starting, but that still falls in 
> the down category.
> 
> Anything else would be a configuration error of the service, which is 
> outside the scope of this discussion.
> 

What I had in mind are situations like Tomcat running out of PermGen space: 
it's up, but completely frozen. 'service tomcat status' says 'up, 'svstat 
/var/service/tomcat' says up, but it's down.

I know, the real fix to this problem is either 'fix Tomcat' or 'use a non-sucky 
service', but those aren't real world solutions in a lot a cases. What would be 
great is for some kind of heartbeat or keepalive API where a service could 
inform the service manager that it is still alive.

-- 
Aaron B. <aaron%zadzmo.org@localhost>