dhcp question

List,

I have a 4.1 GENERIC machine acting as DHCP server, serving
out IP 
addresses to 7 diskless client machines.  Each client
machine needs to 
be pushed a different configuration file in order to start a
process 
once booted.  There is a chance that any number of clients
may be 
replaced at any time.

My initial thinking was to define a range of 7 IP addresses
in 
dhcpd.conf so when the client has got an IP it can then
request a file 
named as the clients IP address from the server.  However if
a client 
needs replacing the new client will dhcp for an address but
dhcpd will 
complain (justifiably) that there are no spare addresses
(the lease-time 
being 1 day).

So if I defined a large pool of IP addresses in dhcpd.conf
that would 
avert the problem described above, however I'm struggling to
think of a 
solution on how would clients would request the correct
configuration 
file? and how could I handle new clients replacing broken
ones with 
regard to dishing out the correct configuration file?

Apologies for such woolly posting, I'm just hoping for some
inspired ideas.

Thanks for your time

On Tue, Jul 03, 2007 at 02:45:00PM +0100, mgb wrote:
> So if I defined a large pool of IP addresses in
dhcpd.conf that
> would avert the problem described above, however I'm
struggling to
> think of a solution on how would clients would request
the correct
> configuration file? and how could I handle new clients
replacing
> broken ones with regard to dishing out the correct
configuration
> file?

Use lladdrs, not IP addresses, to name or serve the files.
This is
how most PXE setups work. See pxeboot(8) for some
discussion.

-- 

o--------------------------{ Will Maier
}--------------------------o
| web:.......http://www.lfod.us/ |
email.........willmaierml1.net |
*------------------[ BSD Unix: Live Free or Die
]------------------*

mgb wrote:
> List,
>
> I have a 4.1 GENERIC machine acting as DHCP server,
serving out IP 
> addresses to 7 diskless client machines.  Each client
machine needs to 
> be pushed a different configuration file in order to
start a process 
> once booted.  There is a chance that any number of
clients may be 
> replaced at any time.
>
> My initial thinking was to define a range of 7 IP
addresses in 
> dhcpd.conf so when the client has got an IP it can then
request a file 
> named as the clients IP address from the server. 
However if a client 
> needs replacing the new client will dhcp for an address
but dhcpd will 
> complain (justifiably) that there are no spare
addresses (the 
> lease-time being 1 day).
>

since these clients are probably wired, why not lower the
lease time to, 
say, 30 minutes? this would allow you to rotate machines
pretty easily 
and have the new one pickup shortly after the old one is
removed. 
depends on how quickly you're planning to rotate the dhcp
clients. 30 
minutes of time between disconnecting one (maybe b/c it's
broken?) and 
reconnecting another to take its place seems reasonable.

if this doesn't cut it fish around for a way to terminate
dhcp leases as 
a function of whether the diskless services are active for a
given 
client. maybe RADIUS could be helpful... don't have much
experience here.

cheers,
jake

> So if I defined a large pool of IP addresses in
dhcpd.conf that would 
> avert the problem described above, however I'm
struggling to think of 
> a solution on how would clients would request the
correct 
> configuration file? and how could I handle new clients
replacing 
> broken ones with regard to dishing out the correct
configuration file?
>
> Apologies for such woolly posting, I'm just hoping for
some inspired 
> ideas.
>
> Thanks for your time