On 02/11/2013 12:13 PM, Dan Williams wrote:
The option you're looking for*is* to set default-duid in the lease
file. That's exactly how you tell NM to use the DUID you want.
Otherwise, NM will generate the DUID-UUID.
See my other message. This appears to be not working.
Do you want me to create a bugzilla report on this?
As I mentioned in other mails to this thread, the DUID-UUID gets used
for a number of reasons (all quotes from RFC 3315):
1) the RFC specifies that the DUID is*per machine*, not per-interface,
and that one DUID is used for any client run on that machine.
Furthermore, "the DUID must be globally unique".
Well, actually, I believe it says "per device". Also, RFC6355 says that
the only solution they consider is firmware based which /etc/machine-id
is not or it would not vary between OS installs.
2) A machine may contain more than one network interface and since under
Linux, interface enumeration is not stable, there's no way to
consistently choose which interface to use for the DUID-LL. Since the
RFC indicates that the same DUID should be used for all interfaces
("each DHCP client and server should have exactly one DUID"), it's
really a toss-up which interface is the "main" interface from which we
should generate the machine-wide DUID.
3) Since the RFCs state that the DUID should not change as a result of
changes to network interfaces, addition/removal of hardware, etc ("a
device's DUID should not change as a result of a change in the device's
network hardware") this implies that it must be stored somewhere. This
causes a problem when network booting or cloning system images, since a
stored DUID would be used for all machines and would no longer be
globally unique as required by #1. Since /etc/machine-id is already
supposed to be globally unique, it must already be handled by the
cloning/network-boot case, and thus we can use it as a basis for the
DUID-UUID without creating extra work for the administrator.
But again, you're free to override this behavior by modifying the
default leasefile in /etc/dhclient6.leases with whatever DUID you
desire.
I had considered /etc/dhclient6.leases and rejected it but I do not
remember why. Now, it seems like the "right" solution. Since almost
all my installs use kickstart, I could set this in my post-install script.
I think I have beaten this dead horse more than enough.
Gene
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