Re: [SSI-devel] SuSE: onsvc

[Bharata B R. <bha...@hp...>]

On Wed, 2005-05-04 at 19:24 +0530, SAMPATHKUMAR KISHORE KANIYAR wrote:
>  Bharata and I discussed on this. We concluded that there is no reason
>  why "localview checkproc" won't work.
>  
>  Bharata is planning to try this. I think he'll send an email after
>  that.

Before this, I am trying to find out why certain services (like sshd)
get started on all nodes while others (like syslogd) get started on only
initnode, even though both of them belong to class 'all'.

Regards,
Bharata.

>  
>  - Kishore
> 
> John Byrne wrote ...
> 
> > On Tue, 2005-05-03 at 19:50 -0700, Brian J. Watson wrote:
> > 
> >>Bharata B Rao wrote:
> >>
> >>>onsvc checks the lock file (/var/lock/subsys/<svcname>) to determine on
> >>>which nodes the specified service is running. And in FC2 every service
> >>>creates/deletes the lock file when started/stopped.
> >>>
> >>>But in SuSE, this lock file isn't created. Most services use startproc
> >>>(8) to start the services. startproc starts the service if it isn't
> >>>already running.
> >>>
> >>>Current issue with onsvc on SuSE is that it fails because no lock files
> >>>exist for any service.
> >>>
> >>>How do we want to handle this ?
> >>>
> >>>Should we use checkproc(8) from inside onsvc to verify if the specified
> >>>service is running on any node ?
> >>
> >>
> >>How does checkproc determine whether a service is running or not?
> >>
> >>I don't think you want onsvc to run checkproc on every node, just to 
> >>determine the set of nodes running a service. This won't scale well on 
> >>larger clusters. Instead, if startproc modifies something on the root 
> >>filesystem that checkproc looks at, then we should leverage that.
> >>
> > 
> > 
> > checkproc and startproc use same method to determine whether a given
> > process is running or not. They take full path of the executable for
> > this. This full path name is searched against all the running processes
> > from /proc. (by doing readlink on /proc/<pid>/exe)
> > 
> > Before taking this long route of checking all processes in /proc, both
> > checkproc and startproc look for a pid file in /var/run/ created
> > optionally by the program. If available, the pid is read from this file
> > and checked if such a process exists.
> > 
> >>From what I have understood till now, startproc doesn't leave anything
> > on root filesystem to note that a given process is running.
> > 
> > Regards,
> > Bharata.
> 
> So, is there any reason localview won't work, then?
> 
> John
>