how to make fedora 10 image from old version

Fedora 10 just came out. If you have an old redhat OS (fedora or CentOS) and you want a new fedora 10 image, to be used as a Xen domainU or a customized Amazon EC2 AMI or whatever, here's how to do it:

Step 1: Create a 2Gig sparse file or lvm and mount it to /mnt.
examples:
for sparse file:
# dd if=/dev/zero of=f10.img bs=1024k count=1 seek=2000
# mkfs.ext3 f10.img
# mount -o loop f10.img /mnt
for lvm:
# lvcreate -L2G -n f10 vg0 (assume you have a volume group called vg0)
# mkfs.xfs /dev/vg0/f10
# mount /dev/vg0/f10 /mnt

Step 2: edit /etc/yum.repo.d/fedora.repo
go to /etc/yum.repo.d, create a new directory, then move everything to the new directory. (you will move them back up to /etc/yum.repo.d after creating fedora 10). Create a new file call fedora.repo with content:
-----------------

[fedora]
name=Fedora 10 - i386
baseurl=http://download.fedora.redhat.com/pub/fedora/linux/releases/10/Everything/i386/os/
mirrorlist=http://mirrors.fedoraproject.org/mirrorlist?repo=fedora-10&arch=i386
enabled=1
gpgcheck=0

-----------------

Step 3: do a "yum groupinstall"
#yum clean all
#yum makecache
# yum --installroot=/mnt -y groupinstall Base
Go have a cup of tea, or read some blogs, or downmod some reddits.
After the installation is complete, to make it actually useable, you need to create these devices:
# MAKEDEV -d /mnt/dev -x console
# MAKEDEV -d /mnt/dev -x null
# MAKEDEV -d /mnt/dev -x zero
And create a root passwd:
# chroot /mnt
# pvconv
# passwd
# exit
Create some files:
# vi /mnt/etc/fstab
# vi /mnt/etc/sysconfig/network
# vi /mnt/etc/sysconfig/network-scripts/ifcfg-eth0
# vi /mnt/etc/resolv.conf
The contents of these files depends on your settings, use the files on your current OS as references.

That's it, you're done. Unmount the image. Now you should be able to boot it. After you boot it(e.g. as a Xen domU), do some configurations. These are what I did:
# chkconfig NetworkManager off
# chkconfig network on
# service NetworkManager stop
# service network start #use network instead of NetworkManager
# chkconfig atd off
# chkconfig bluetooth off
# chkconfig cups off
# chkconfig haldaemon off
# chkconfig ip6tables off
# chkconfig mdmonitor off
# chkconfig netfs off
# chkconfig netfs off
# chkconfig nfslock off
# chkconfig pcscd off
# chkconfig portreserve off
# chkconfig rpcbind off
# chkconfig rpcidmapd off
# chkconfig rpcgssd off #all these services are useless for me
# yum install xfsprogs #my filesystem is xfs
# vi /etc/rc.d/rc.sysinit #comment out a bunch of lines to get rid of false err/warning device-mapper messages during boot-up

Don't forget to delete (in your current OS) fedora.repo in /etc/yum.repo.d and move everthing back in there.

Super Easy Python powered Christmas light controller for $40

There're lots of ways to control Christmas lights. The easiest (but expensive) is just getting a lightorama. I'm not spending $400 on a controller. So I decided to build my own.

Computer Christmas has many articles showing you how to do this. There's a how-to for a 320 channel controller. All I need is 8 channel on/off (no dimming), so a simple parallel port relay box is perfect for me. This how-to tells you how to building one. But actually you don't need to build a relay box yourself, there are parallel port relay kits sold online for cheap. You just buy the kit and connect to electric box.

So Here's how to build a Python powered Xmas light controllers for $40(more or less).

1, get a parallel port relay kit for about $32, for example: here or here. You can get it assembled or in module form for a few more bucks. I didn't want to spend much time assembling so I got a module.

2, get electric box and outlets from Homedepot or Loews for total $8. Again I'm lazy so I just got a power strip from Walmart for $4, but it only has 7 outlets, I couldn't find one with 8.

3, Wire the kit to your electric box.

4, Connect to computer and fire up Python (see my previous post).
Video of testing session.

Here's source code for the GUI program (in wxpython), most of code were generated by wxglade, I just created the event handlers for the mouse clicks. The speed control (slider) is not implemented yet.