[mythtv-users] Diskless Front End (again)

[Rich West]

Jeff Coffler wrote:
> I have netboot working successfully on FC6.
>
> My server is an FC6 system, and my clients are FC6 systems as well.  The 
> server and client run different kernel versions.
>
> I need learn some things when looking at the Wiki on this stuff.  First, 
> if you haven't looked at the Wiki, you MUST:
>
> http://www.mythtv.org/wiki/index.php/Diskless_Frontend#Redhat_and_Fedora_Core
>
> It's a fantastic starting point.
>
> Second, system-config-netboot in FC6 works just fine for setting all 
> this up, although the final environment does need a bit of tweaking.  
> Lastly, there is some documentation available from RedHat on this:
>
> http://www.redhat.com/docs/manuals/enterprise/RHEL-4-Manual/sysadmin-guide/
>
> See chapters 3 and 4.
>
> Now, the things I learned along the way:
>
> 1. IMPORTANT!  When you run system-config-netboot, it makes changes to 
> the diskless boot root area.  For example, /etc/mtab is modified to be a 
> symbolic link to /proc/mounts.  When you run system-config-netboot, it 
> creates "marker" files to it knows it did this stuff.  But if you change 
> things in the diskless boot root area "behind it's back", you can 
> seriously confuse things.  End result: If you make changes to the "boot" 
> system on the original hard drive, I've found it's best to blow away the 
> root on your server and rsync it again.  (-del may work on the rsync; I 
> haven't tried that.)
>
> 2. Follow the directions in the WIKI *exactly*.  If you're in trouble, 
> blow away your root area and start all over again from scratch.  
> Deviation will cause grief.  For example, I thought "Hey, I can just 
> maintain hard links and save disk space!"  Nope; when I tried rsync to 
> maintain hard links, errors followed.
>
> 3. After you get the root area rsync'ed, and you run 
> system-config-netboot to create the boot images on your server, then you 
> need to mount the boot image via loopback and make the following changes:
>
> 3a) Copy mount.nfs from <diskless-boot-root>/sbin/mount.nfs to 
> <boot-image)/sbin/mount.nfs
> 3b) In the disklessrc file (in / of the diskless-boot-root image), do:
> 3b.1) Modify the mount of the .snapshot area to include -n (no write 
> access to /etc),
> 3b.2) Add a line after that mount to remount the .snapshot area RW (not 
> sure why it gets mounted RO, but it does)
>
> After all that is done, umount the loopback image, recompress it, and 
> copy it to the boot image on the server for the diskless system.
>
> I found that 3a was in the Wiki link, as well as 3b.2, but 3b.1 wasn't 
> there.
>
> After doing all this, I got my FC6 system netbooting.  It's a good thing.
>
> One other tidbit:
>
> I use mythvideo, so I want video content mounted from the server.  I 
> found that putting this in the snapshot's /etc/fstab file didn't work 
> (again, no write access to /etc for the mtab tmp file).  So I don't do 
> this, but instead modified /videos/addons (on the diskless boot system) 
> to be a symbolic link to "/net/<server-name>/<export-path to addons 
> directory on server>" (i.e. I get at it via automount).  This eliminates 
> the problem for me, and allows me to use MythVideo properly on the 
> diskless boot system.
>
> Hope this helps.  If someone else gets this working successfully 
> following my instructions, let me know, and I'll update the Wiki!

I'll give it a shot tonight! :)

-Rich