NFS export question && diskless dirs

[James]

On Thu, 2007-10-11 at 23:03 +0200, mr. phreak wrote:

> James wrote:
> > On Thu, 2007-10-11 at 22:36 +0200, mr. phreak wrote:
> >> James wrote:
> >> >
> >> >
> >> > On Thu, 2007-10-11 at 21:23 +0200, mr. phreak wrote:
> >> >> hi. I have a question regarding NFS-exports.
> >> >>
> >> >> /etc/exports
> >> >> /diskless/ro    -ro -maproot=root leia
> >> >> /diskless/kernels leia
> >> >> /diskless/rw   leia
> >> >> /usr    -ro -alldirs leia
> >> >> /home   -alldirs leia
> >> >> /etc    -ro -alldirs -maproot=root leia
> >> >>
> >> >> but mountd only recognize /diskless/ro - /usr - /home/ and /etc 
> >> >> (showmount -e). How can I export
> >> >>
> >> >> /diskless/ro -ro && /diskless/kernels with rw && /diskless/rw with rw 
> >> >> tothe same host???
> >> >>
> >> >> Also, I have another question. Is it possible to run a diskless system 
> >> >> with /var and /tmp mounted
> >> >> on a NFS-mount instead of using memory-disks? If possible, I'd gladly 
> >> >> appreciate some tips or
> >> >> links.
> >> >>
> >> >> Best regards,
> >> >> J
> >> >> _______________________________________________
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> >> >>     
> >> >
> >> >
> >> >
> >> > Check out the handbook page on NFS:
> >> >
> >> > http://www.freebsd.org/doc/en_US.ISO8859-1/books/handbook/network-nfs.html
> >> >
> >> >
> >> > "In /etc/exports, each line represents the export information for one 
> >> > file system to one host. A remote host can only be specified once per 
> >> > file system, and may only have one default entry. For example, assume 
> >> > that /usr is a single file system. The following /etc/exports would be 
> >> > invalid:
> >> >
> >> > # Invalid when /usr is one file system
> >> > /usr/src client
> >> > /usr/ports client
> >> >
> >> > One file system, /usr, has two lines specifying exports to the same 
> >> > host, client. The correct format for this situation is:
> >> >
> >> > /usr/src /usr/ports client
> >> >
> >> > The properties of one file system exported to a given host must all 
> >> > occur on one line. Lines without a client specified are treated as a 
> >> > single host. This limits how you can export file systems, but for most 
> >> > people this is not an issue." 
> >>
> >> Yeah, I know. I read it as well. I guess I'll have to create separate 
> >> filesystems if I want to export them with different permissions to the 
> >> same host... I thought the mountd -r was a sollution to skip that. But I 
> >> guess I was
> >> wrong.
> >>
> >>     
> >
> >
> > Reading on in the handbook has this:
> >
> > The following is an example of a valid export list, where /usr and 
> > /exports are local file systems:
> >
> > # Export src and ports to client01 and client02, but only
> > # client01 has root privileges on it
> > /usr/src /usr/ports -maproot=root    client01
> > /usr/src /usr/ports               client02
> > # The client machines have root and can mount anywhere
> > # on /exports. Anyone in the world can mount /exports/obj read-only
> > /exports -alldirs -maproot=root      client01 client02
> > /exports/obj -ro
> >
> >
> >
> > The handbook claims that /exports is a single file system, yet it treats /exports/obj as a separate entity
> > on a separate line. I was wondering if this was a result of /exports being exported in its entirety. You might
> > want to goof around with that, see if it'll let you do what you want to do.
> >
> >   
> I've played around, and my conclusion is that you can have the same 
> dirs/filesystems on seperate lines, IF the host entry isn't the same. 
> i.e if the example above would have client01 and client02 on /export/obj 
> it would be a
> erratic entry. However it's a shame because it means you cannot export 
> subdirs of a same filesystem with different permissions to the same host(s).



Well, now, that gives some hope. Open up /etc/hosts and make a couple of
junk entries, like:

 192.168.1.77 junkhost.host
192.168.1.78 junkhost2.host

And use *them* in your exports to differentiate each nfs line. Even
better, don't use hostnames in /etc/exports, just use junk ip
addresses. 

That *surely* can't be the only way to permanently differentiate the
lines, but it might be a good way to start.


James