How to reload /net "maps"

How to reload /net "maps"

[Greg Wooledge]

Debian 5.0, autofs 4.1.4, kernel 2.6.26-2-686

I may be overlooking some documentation, but I couldn't find out how to
do this.  Occasionally one of our NFS servers adds a new entry to its
/etc/exports file, and we'd like the clients to be able to use it.

The clients look like:

# grep -v '^#' /etc/auto.master
/net    /etc/auto.net

At some point in the past, autofs will have contacted this host and
somehow "cached" the fact that it was sharing /home, /data, etc.
Now I've added /opt to the exports file.  But when I do "ls /net/servername"
I still only see home and data, not opt.

Rebooting the client works -- after a reboot, I can see home, data and opt.

I'm trying to find a way to get autofs to reload the server's list of
shared file systems without totally rebooting the client.  If I issue
a "/etc/init.d/autofs reload" command, I get a few normal-looking messages,
but no change in the list of results.  If I try "/etc/init.d/autofs restart"
it tell me it cannot stop the /net daemon, and cannot start a new one.
Manually attempting "kill PID" or "kill -HUP PID" has no visible effect.

Re: How to reload /net "maps"

[Jeff Moyer]

Greg Wooledge <wooledg@eeg.ccf.org> writes:

> Debian 5.0, autofs 4.1.4, kernel 2.6.26-2-686

Very old autofs version.  You should transition to version 5.

> I may be overlooking some documentation, but I couldn't find out how to
> do this.  Occasionally one of our NFS servers adds a new entry to its
> /etc/exports file, and we'd like the clients to be able to use it.
>
> The clients look like:
>
> # grep -v '^#' /etc/auto.master
> /net    /etc/auto.net
>
> At some point in the past, autofs will have contacted this host and
> somehow "cached" the fact that it was sharing /home, /data, etc.
> Now I've added /opt to the exports file.  But when I do "ls /net/servername"
> I still only see home and data, not opt.

/etc/auto.net is a program map that returns a multimount entry.  What
that means is that once you traverse into the directory /net/servername,
autofs no longer traps lookups (it does it for the initial mount, but
that's it).  You can get the new export to show up if you managed to get
all applications out of that directory hierarchy, then forced automount
to expire the mount, and then accessed it again.

> Rebooting the client works -- after a reboot, I can see home, data and opt.
>
> I'm trying to find a way to get autofs to reload the server's list of
> shared file systems without totally rebooting the client.  If I issue
> a "/etc/init.d/autofs reload" command, I get a few normal-looking messages,
> but no change in the list of results.  If I try "/etc/init.d/autofs restart"
> it tell me it cannot stop the /net daemon, and cannot start a new one.
> Manually attempting "kill PID" or "kill -HUP PID" has no visible effect.

autofs version 5 may be better in this regard.  I'll let Ian comment on
whether what you want to work is expected to work.

Cheers,
Jeff

Re: How to reload /net "maps"

[Ian Kent]

On Thu, 2010-09-09 at 16:04 -0400, Jeff Moyer wrote:
> Greg Wooledge <wooledg@eeg.ccf.org> writes:
> 
> > Debian 5.0, autofs 4.1.4, kernel 2.6.26-2-686
> 
> Very old autofs version.  You should transition to version 5.
> 
> > I may be overlooking some documentation, but I couldn't find out how to
> > do this.  Occasionally one of our NFS servers adds a new entry to its
> > /etc/exports file, and we'd like the clients to be able to use it.
> >
> > The clients look like:
> >
> > # grep -v '^#' /etc/auto.master
> > /net    /etc/auto.net
> >
> > At some point in the past, autofs will have contacted this host and
> > somehow "cached" the fact that it was sharing /home, /data, etc.
> > Now I've added /opt to the exports file.  But when I do "ls /net/servername"
> > I still only see home and data, not opt.
> 
> /etc/auto.net is a program map that returns a multimount entry.  What
> that means is that once you traverse into the directory /net/servername,
> autofs no longer traps lookups (it does it for the initial mount, but
> that's it).  You can get the new export to show up if you managed to get
> all applications out of that directory hierarchy, then forced automount
> to expire the mount, and then accessed it again.
> 
> > Rebooting the client works -- after a reboot, I can see home, data and opt.
> >
> > I'm trying to find a way to get autofs to reload the server's list of
> > shared file systems without totally rebooting the client.  If I issue
> > a "/etc/init.d/autofs reload" command, I get a few normal-looking messages,
> > but no change in the list of results.  If I try "/etc/init.d/autofs restart"
> > it tell me it cannot stop the /net daemon, and cannot start a new one.
> > Manually attempting "kill PID" or "kill -HUP PID" has no visible effect.
> 
> autofs version 5 may be better in this regard.  I'll let Ian comment on
> whether what you want to work is expected to work.

We still can't change entries with possible hierarchic relationships
while they are in use in version 5, because of the potential
dependencies.

> 
> Cheers,
> Jeff
> 
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