If the systems have more than one IP address (e.g, provisioning & IPoIB), using 
the nics table along with either “confignics –s” or “confignetwork –s” will 
configure all interfaces as static.

Regards,
Christian Caruthers
Lenovo Professional Services
Mobile: 757-289-9872

From: RUSSELL AULD <russa...@comcast.net>
Sent: Saturday, August 24, 2019 9:05 PM
To: xCAT Users Mailing list <xcat-user@lists.sourceforge.net>
Subject: [External] Re: [xcat-user] DHCPLEASE for stateless cluster


The postscript is 'hardeths'


On August 20, 2019 at 3:54 PM Kevin Keane 
<kke...@sandiego.edu<mailto:kke...@sandiego.edu>> wrote:
Remember that the DHCP in xCAT is quite substantially different from "normal" 
enterprise DHCP, since it needs to only serve a very specific, well-defined, 
set of computers (all of which normally will have static reservations), except 
during discovery.

I would simply use whatever the default value is. Or if you do want to tweak 
it, go for a very long duration (to reduce traffic, even if it is only by a 
tiny amount).

The other big difference between Enterprise DHCP and xCAT DHCP is that, because 
your xCAT environment is (or should be) very well-defined, it's very unlikely 
that the DHCP server just crashes out of the blue. If the DHCP server crashes, 
you probably have a bigger problem.

BTW, a 3 day lease time wouldn't be enough to protect against a weekend outage. 
The lease time needs to be at least twice the longest expected outage.

If you do want to protect against a DHCP failure anyway, you can do a few 
things:

- Configure an automatic restart with a cron script or the like.
- Configure the nodes to use a static IP address after bootup. There is a node 
attribute to do that, but I don't recall what it is off the top of my head. 
This is actually done in a postscript.

_______________________________________________________________________
Kevin Keane | Systems Architect | University of San Diego ITS | 
kke...@sandiego.edu<mailto:kke...@sandiego.edu>
Maher Hall, 192 |5998 Alcalá Park | San Diego, CA 92110-2492 | 619.260.6859 | 
Text: 760-721-8339

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On Mon, Aug 19, 2019 at 11:06 PM Heckes Frank (CI/OSB4) via xCAT-user < 
xcat-user@lists.sourceforge.net<mailto:xcat-user@lists.sourceforge.net>> wrote:

Hello all,



I’ve a couple of questions concerning the dhcpd configuration of a cluster
runining completely on stateless images.



-1- What is ‘best’ choice for the value of the DHCPLEASE parameter to run
     a stateless cluster?

     In case of dhcpd failures is seems to be helpful assigning a higher value
     then the default for at least 3 days seems to reasonable in case the
     dhcpd crashes over the weekend and an automated check/restarted fails.(?)
-2- Does my understanding (dhcpd.leases(5)) and experience is right that the 
leases stored
     in /var/lib/dhcpd/dhcpd.leases guarantee a persistent state during dhcpd 
restarts?



Many thanks in advance.



Cheers,

-Frank Heckes
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