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CentOS diskless clients authenticate to windows AD

Posted on 2009-04-22
Medium Priority
Last Modified: 2013-12-06
I am working on using diskless clients with CentOS. I have the diskless clients working fine. My next step is to have the clients boot up and authenticate with their host name which is aready in AD.

I have sucessfully built non-diskless client machines using CentOS and joined them to my domain. I used one of these machines to build the diskless image.

My thoughts are that I need to put the correct files/directories into a files.custom file in the snapshot folder.

I'm looking for any thoughts/help on this project.

Question by:RandyReichert
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LVL 81

Expert Comment

ID: 24243956
I think you addressed the complexity in your question.
Does each diskless  client have an NFS mount point where it can store its configuration? i.e. /etc?
Presumably you do not want to configure each diskless client.

Author Comment

ID: 24244725

Thanks for your reply. I have gotten past the last stumbling block. I just needed to get the right combination of files into the files.custom folder.

To answer your question, yes, each will have it's own mount point. I do understand that there will be some individual customization of files for each client that I want to add.

My next task is to configure the netboot so that hosts are not IP specific.
LVL 81

Expert Comment

ID: 24245837
netboot uses the MAC address and not the IP.
The issue is with assigning/setting the hostname.  The network can be set by DHCP as long as the hostname is loaded which might be the stumbling block you are addressing.
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Author Comment

ID: 24250413
Your sort of correct....

When you create the host using netboot, you have to enter in an IP or IP subnet. A file is created in the /tftpboot/linux-install/pxelinux.cfg folder that is given the name of the IP or subnet you enter in hex. When you boot up the client, the first request it makes to find that file is with the MAC address and then it looks for the full IP in hex and keeps going, reducing each request by a subnet, until it gets a match.

I can rename the file to the MAC address, so as to eliminate the IP requirement. Then the entry dissappears in the netboot software....not really a big deal.

I will now create a snapshot folder for each host and set the name inside of there.

Your right, I could do it by DHCP, however our DHCP is being done by the Cisco router, and I don't want to put any requirements on it to handle that.

Make any sense? Lol!
LVL 81

Accepted Solution

arnold earned 2000 total points
ID: 24250565
Do you have a reserved block on the segment that the DHCP server does not allocate?
The cisco is configured to relay the bootp requests to the netboot server, right?
Not sure whether it is an option, but you could through netboot assigned the IP to be used on the diskless client.

Or add a process that maintains the rarp map MAC to IP.
using symbolic links.
I.e. periodically run through the directory where the files are stored. get the IP based file list. ping the destination and check the ARP table associated with the IP.
Then create the link to the mac addressed based file and the IP.

Author Comment

ID: 24250685
I'm not able to do it through netboot as the IP has already been assigned by DHCP by the time the pxe process starts.

Basically my requirement was to have the diskless clients boot up and maintain a separate host name that is already in active directory, without the use of a static IP. This would then allow the user to log in using their AD username and password.

The stumbling block after that was to figure out a way to do this without using a pre assigned IP by netboot. I have accomplished this by renaming the file to the MAC address, thus always retaining the same snapshot and in conjunction, the same hostname. Obviously, the downfall is that if a system is replaced, the file must be updated with the correct MAC address.

Your last suggestion using the rarp map MAC to IP I do believe would work.

I am going to close this out and award points as you have been helpful and given me some new areas to explore with this project.

Thanks for your help Arnold.

Author Closing Comment

ID: 31573371
Thanks again.

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