Enterprise Datacenter Management Voodoo
Posts tagged xCAT
Rails and other web services on the same box
Apr 27th
The Sumavisor is built on top of xCAT. The Sumavisor is a rails application, with lots of xCAT plugins that sit on top of the base xCAT. One thing we had to work out was having a web server host a rails application (the Sumavisor) and allow xCAT to install nodes via HTTP. The solution is quit trivial thanks to my friend Ben. You simply add one line in the directories you don’t want Passenger to run in. So for xCAT, you put in /etc/httpd/conf.d/xcat.conf
<Directory “/tftpboot”>
Options Indexes +FollowSymLinks +Includes MultiViews
AllowOverride None
PassengerEnabled off
Order allow,deny
Allow from all
</Directory>
<Directory “/install”>
Options Indexes +FollowSymLinks +Includes MultiViews
AllowOverride None
PassengerEnabled off
Order allow,deny
Allow from all
</Directory>
That makes it so my code all runs very nice 
Windows SAC (special administration console)
Mar 11th
Installing Windows remotely I’ll sometimes only be able to see the SAC> on the remote console output since I may not have a graphical viewer to do rdp or some other tricky way.
Once SAC boots up I can access the command prompt by doing the following:
cmd
(It then gives you a name like cmd001)
Switch to it:
ch -sn cmd001
Now enter the user name, I usually don’t enter any domain, and then enter the password. Once done you can log in and run commands!!
C:\Windows\system32>diskpart Microsoft DiskPart version 6.0.6001 Copyright (C) 1999-2007 Microsoft Corporation. On computer: I02 DISKPART> list disk Disk ### Status Size Free Dyn Gpt -------- ---------- ------- ------- --- --- Disk 0 Online 233 GB 0 B DISKPART> select disk 0 Disk 0 is now the selected disk. DISKPART> list partition Partition ### Type Size Offset ------------- ---------------- ------- ------- Partition 1 Primary 233 GB 1024 KB DISKPART>
xCAT and RHAS4 update 4
Aug 25th
Recently I had to add support for xCAT to install Red Hat 4 update 4 for a project I was working on. I’m using development versions of xCAT 2.3 before all the xnba stuff got put in, so its a real hodgepodge of code.
Here is how I did it.
1. copy the cds:
copycds -n rh4 RHEL4-U4-x86_64-AS-disc*.iso
2. Make a new tree:
cd /opt/xcat/share/xcat/install cp -a rh rh4
3. Edit Kickstart file
RH4 update 4 doesn’t have the –key skip option like it does in RH5 so I had to edit that out of the kickstart template in
cd /opt/xcat/share/xcat/install/rh4/ mv compute.rhel4.tmpl compute.tmpl
4. Install a node:
rinstall i03 -o rh4 -p compute -a x86_64
5. Sit back and relax! …Well, if you boot the right node. Turns out I had new hardware and an old OS! So it cried that it couldn’t find the disk driver of a dx360 M2. Now I really didn’t want to go down that path of patching the kernel and ramdisk. I used to do that a lot for systems… So this time, I was fortunate in that I had an older machine (x346) that I could just use instead…
Whew!
Its so nice when things work right away.
Suggestion for IBM make an UpdateXpress that supports PXE boot!
Aug 24th
Downloading firmware for Intel Servers is a bear. IBM has tried to make it easier by providing an update CD that has all the various subsystems in it. This is a pretty good idea. But the problem is, in my world, I need to PXE boot all the servers to an image or run a package on the individual machines.
For example, if you have an HS21 xM server, you can go to this page and you are shown all the different subsystems that you can update. My goodness! That is a lot of work. Not to mention that you may not know what a lot of them are.
IBM is doing two things right:
1. They let you update packages right on the command line if you’re running Linux. This is great if I want to update the BIOS on my machines. I just scp the binary to all the machines and run the update and reboot. Boom! Just like that the BIOS is updated. Nice job IBM. In fact, they even let you change BIOS/CMOS settings from the command line. Much easier than waiting for the boot up screen and pressing F2.
2. They have a tool UpdateXpress System pack that has all the updates in it. This tool is basically a bootable CD that has all the updates. You stick the CD in the system then reboot the system and it updates ALL of the system components.
So that’s what they’re doing right. And the thing is, IBM is soooo close to getting it perfect. What do they need to do?
Well, I need the functionality of #2 in a PXE boot environment. Turns out you can’t network boot that UpdateXpress CD that you created. If you could then think how great it would be? You could just take that and put into xCAT and boot all nodes to this PXE boot environment. But they don’t.
I for one, can not afford to take a CD to every machine in my server farm and watch it boot up and do it. I need a PXE boot environment. On the other hand, it takes me a good 2 hours to go through IBM’s website and get all the binary updates that run on the Linux command line. Once I have them all I had to create my own PXE boot environment that would run under xCAT.
I took about 3 days of work to make such an environment work under xCAT’s service kernel. So when I want to update HS22s or LS22s I do:
nodeset compute runimage=http://mgmt/install/updates/hs22v.tgz
You can get my images for HS22′s and LS22′s here
I’ve been creating images like this since 2003 for IBM hardware. I hope that soon I won’t have to anymore. Before I was making DOS images and PXE booting those with memdisk. It’s great that I can now do everything with Linux. IBM is almost there. Once they get the Update Xpress to PXE boot, we’re golden.