[Freeipa-devel] automount in LDAP

[Simo Sorce]

On Thu, 2008-11-06 at 08:52 -0500, Rob Crittenden wrote:
> Nalin Dahyabhai wrote:
> > On Wed, Nov 05, 2008 at 04:49:57PM -0500, Rob Crittenden wrote:
> >> Ok, here is some LDIF that will define some defaults. I haven't tackled  
> >> auto.home yet.
> > [snip]
> >> So adding a new direct mount is as simple as:
> >>
> >> ipa automount-addkey --key=share --info=server:/share auto.direct
> > 
> > Slick!
> > 
> >> Nalin, if I create an auto.home map that handles /home is that going to  
> >> confuse local accounts who exist on /home? That happens on Solaris and  
> >> has always driven me nuts.
> > 
> > Yes.  On Linux, at least, /home becomes a mount point for an autofs
> > filesystem, and behaves like other mount points (meaning whatever was
> > there before the filesystem was mounted is hidden until it's unmounted
> > again).
> > 
> > You could get around that using the direct map, but that requires more
> > resources, maybe too many.
> > 
> > I don't have hard numbers to back it up, but I expect that heavy users
> > of the automounter make sure to either store home directories for local
> > users elsewhere on the filesystem (/export?), or to use some other
> > location for the mountpoint (in school, we used /ncsu).
> > 
> 
> Ok, so how about an API to create indirect maps. Then all one would need 
> to do is add the keys (mounts) needed.
> 
> As I understand it a new indirect map requires 2 entries, one that 
> defines the map name itself and one that associates the mount point with 
>   that map.
> 
> So it might look something like:
> 
> % ipa automount-addindirect --root=/export auto.export
> 
> This will create these two entries:
> 
> dn: automountmapname=auto.export, cn=automount, $SUFFIX
> objectclass: automountmap
> 
> dn: automountkey=/export, automountmapname=auto.master, cn=automount, 
> $SUFFIX
> objectclass: automount
> automountinformation: ldap:automountmapname=auth.export, cn=automount, 
> $SUFFIX
> automountkey=/export

Where is the server being specified ?

> Then you could add a new key with:
> 
> % ipa automount-addkey --key=src --info=server:/exports/stuff/src 
> auto.export
> 
> And then have /export/src available.
> 
> If I'm reading this right this should be equivalent to:
> 
> auto.master:
> 	/export	auto.share

what is auto.share?

> auto.export:
> 	src	server:/exports/stuff/src
> 
> What this buys one is that the admin adding the indirect map doesn't 
> need to worry about the details of the automountinformation attribute.
> 
> Does this make sense?

So to recap, this basically "remaps" where exports appears ?

> And one more question. If I want to provide some mount options, say 
> -ro,soft, where are those applied? I assume it goes into the attribute 
> automountInformation but is it a prefix or a suffix:
> 
> So:
> 
> automountInformation: server:/exports/stuff/src -ro,soft
> 
> OR
> 
> automountInformation: -ro,soft server:/exports/stuff/src


Looking at this discussion, it is unclear to me how geographical
situations are handled. If I have IPA server in 3 continents, are we
making all clients still try to connect to servers in other continents ?

How do clients choose which server to connect to ?

Is there any concept like that in automount ? Should we care ?

Simo.

-- 
Simo Sorce * Red Hat, Inc * New York