hostname problem with snmpd

[Frank.Fock____t-online.de]

Hi Dave,

I suspect the kill-9 being the problem. The hostname
ist not stored in the persistence data storage by
default. However it can be indirectly used by the
SNMP-TARGET-MIB. But anyway, kill-9 while the agent
writes data to the persistent storage files will
invalidate them. A fail-safe solution would be to
backup the old ones on every start-up (and use them
if an error is detected with the new ones, i.e. they
have not been completely written...)

Best regards,
Frank

Dave Mason schrieb:
> One other thing I forgot to include.  When the hostname
> is changed as I 
> mentioned, the graceful kill with SIGTERM doesnt work, so
> we have to use 
> "kill -9" in step 5 below.  Not sure if that's a symptom
> of this 
> problem, or something that has another cause but that in
> turn causes 
> this problem.  For some time I thought the kill -9 could
> be corrupting 
> the data files, but I can copy them to another system,
> load them into an 
> agent, and the agent will run OK.  It seems that only on
> the original 
> system where the hostname was changed is there a
> problem.
> 
> As you can guess I'm a bit lost on this one - thanks for
> any help you 
> might have or suggestions for where to start.
> Dave
> 
> Dave Mason wrote:
> 
> > Hi,
> > I'm having a strange problem where a user is changing
> the hostname to 
> > something that doesnt resolve, and the agent does not
> respond even 
> > after the hostname is restored to its proper value. 
> The problem can 
> > only be fixed by deleting the persistence data files
> and restarting.  
> > Here's the full sequence:
> >
> > 1. set hostname to something that DNS can't resolve,
> ie
> >   hostname xxx
> > 2. start snmpd as usual.  The same problem also happens
> if the agent 
> > is already running before the hostname is changed.
> > 3. try some SNMP GETs.  They fail as expected.
> > 4. restore hostname to it's proper value, which DNS can
> resolve
> > 5. restart snmpd with persistence data files from
> before.
> > 6. try SNMP GETs.  agent still does not respond.
> > 7. to fix. stop the agent, delete persistence data
> files, and restart.
> >
> > The obvious answer is to avoid screwing up the host
> name, but 
> > customers being customers, they want a solution.  They
> believe the 
> > agent should work fine once the hostname is restored,
> and they don't 
> > want to lose their persistence data.  Is it possible
> that the hostname 
> > is written into the persistence files somewhere,
> causing problems once 
> > it's changed?
> >
> > We have had some other issues with persistence files,
> so I'm also 
> > curious as to what is going on.  We're running on Red
> Hat 7.3, agent++ 
> > version 3.5.3a, snmp++ version 3.1.6c.
> >
> > Regards,
> > Dave
> >
> 
>