[Bioclusters] alternative DHCP implementations?

Chris Dagdigian dag at sonsorol.org
Tue Mar 29 11:52:39 EST 2005

Hi folks,

Anyone using non-ISC implementations of DHCP services on Linux or Mac OS X?

With "old" versions of ISC DHCP the server would hand out IP addresses 
from the Dynamic range one at a time, starting from the lowest number 
and moving incrementally upwards in the range.

This made cluster deployment and node naming an easy process:

1. set up dynamic IP range for initial boot
2. power on nodes in the order in which you want them named
3. nodes get IP addresses & hostnames assigned from 1 .. N
4. Scrape the dhcpd.leases file to pull MAC addresses out for all nodes
5. Use MAC info to create dhcpd.conf entries for static-by-mac allocation
6. Reboot cluster; all nodes are now named/numbered correctly

The "current" version of ISC DHCP (Internet Systems Consortium DHCP 
Server V3.0.2) has much different behavior:

- It "usually" gives out IP address in backwards order, starting from 
the highest number in the range and going down incrementally by one each 
time a lease is assigned.

The end result is that freshly booted clusters get "named backwards" 
from node0NN ... node001. This does not break anything but does cause 
"extra work" in settings where previously we would rely on DHCP to 
assist us with initially naming/numbering nodes in cases where MAC info 
is not known ahead of time.

Even this behavior is not absolute. The docs seem to indicate now that 
dynamic IPs are stored in a hashtable like element and that there is 
*no* way to predict or control the order in which dynamic leases are 

We are thinking about trying to find a replacement DHCP server that has 
a predictable method of allocating dynamic IP addresses (even if only 
for the initial cluster deployment)  Has anyone done this? Any suggestions?


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