When my colleague Pavel Emelyanov returned from the 2008 Linux kernel summit back in September he brought a small present for me -- a Gumstix Overo (every LKS participant got one for free; yet another reason to become a high-profile kernel developer!). Overo is a computer (well, actually a set of boards and cables) with a CPU board the size of a gum stick, featuring TI OMAP3 CPU, 128 megs of RAM and a microSD slot. It also has 802.11g Wi-Fi and Bluetooth but those happens to be completely dead as this the first beta release of hardware.

For the last few days I was digging into a project to make OpenVZ running on this Overo thing. That involved patching OpenVZ kernel to support ARM architecture, building vzctl package (.ipk) for ARM using bitbake, and creating a template.

It was amazingly easy to port the OpenVZ kernel to ARM; you can see here that besides a big-all-in-one-openvz-for-2.6.27 patch I only had to add 4 tiny ARM-specific patches (1, 2, 3, 4). For vzctl, it was even easier -- all I had to do is to add openvz syscall numbers for ARM which were added, and create a bitbake recipe file.

Creating a template for ARM architecture was tougher but I managed to win that fight, too -- you can find a Debian Lenny template here.

Here is an except from a terminal session showing OpenVZ on Overo:

root@overo:~# uname -a
Linux overo 2.6.27-omap1 #1 Tue Oct 21 21:19:40 MSD 2008 armv7l unknown unknown GNU/Linux

root@overo:~# cat /proc/vz/version
037test001

root@overo:~# vzlist
CTID NPROC STATUS IP_ADDR HOSTNAME
777 5 running - -

root@overo:~# vzctl enter 777
entered into CT 777
-bash-3.2# ps axf
Unknown HZ value! (0) Assume 100.
PID TTY STAT TIME COMMAND
310 ? Ss 0:00 vzctl: pts/0
311 pts/0 Ss 0:00 \_ -bash
313 pts/0 R+ 0:00 \_ ps axf
1 ? Ss 0:00 init [2]
208 ? Sl 0:00 /usr/sbin/rsyslogd -c3
227 ? Ss 0:00 /usr/sbin/cron


Please note that all this is still in very alpha stage -- there are errors, bugs, ugly warnings, you have to modify some things in place etc. But it's working. If someone is interested in running OpenVZ on ARM hardware, please let me know -- leave a comment here or email kir (A) openvz (.) org.

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