Chris Dagdigian wrote: > > > Agreed. It was just a shortcut. We already do allocation of IP based > on MAC address but that only works when you know the MAC address > information ahead of time. This is rare especially on whitebox > cluster projects where people don't put the MAC on the product > packaging or on the chassis itself. Some vendors do a good job of > making the data easy to find and others simply don't bother. > > A dhcp server handing out dynamic-range leases in a predictable manner > is what allowed us to easily map MAC address to node position and > nodename simply by powering on the nodes for PXE boot in the order in > which they are racked and stacked. Once this was done we had the > MAC->Node mapping data we needed to generate the static allocation > entries. > > A workaround for non-predictable allocation is to simply power on the > cluster in the order in which you want things named, then parse the > dhcpd leases file for both the MAC address *and* the timestamp > representing the lease handout. That would allow you to map MAC -> > Node without having to care about hostnames for the first pass MAC > collection phase. Then you build the static-by-mac entries into the > conf file and problem solved. If we stick with ISC DHCP this is a > possibility... Or buy an switch with a bit of inteligence that can dump the machines MAC addresses based on ports. > > c > > Adam S. Moskowitz wrote: > >> Chris, >> >> >>> 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) >> >> >> >> I think it's a bad idea to rely on such behavior. I don't remember what >> the RFC says, but in general, unless the RFC guarantees an >> implementation should behave a particular way, you are asking for >> trouble to rely on specific behavior. >> >> A great example of this is how round-robin DNS used to work and then how >> it changed and lots of things broke. >> >> DHCP isn't meant to do what you're asking it to do, so I strongly >> suggest you not use it to solve that particular problem. >> >> That said, DHCP supports a mechanism for binding specific IP addresses >> to specific MAC addresses, even though the assignment is still done >> dynamically. Yes, this is a bit more work, but at least it's guaranteed >> behavior. > > _______________________________________________ > Bioclusters maillist - Bioclusters at bioinformatics.org > https://bioinformatics.org/mailman/listinfo/bioclusters > -- Mvh|Regards, Lars System Administrator, Phone: 3532 1349, Room: 318 Bioinformatics Centre, University of Copenhagen, Universitetsparken 15 DK-2100 Copenhagen DENMARK