Custom Qcow2 Images
Pete Wright
pete at nomadlogic.org
Fri Jul 19 02:53:46 UTC 2019
On 7/14/19 4:37 PM, Pete Wright wrote:
> Hey there folks,
> I am wondering if anyone has any pointers on creating a custom Qcow2
> FreeBSD that is akin in size to nanobsd. I have an environment where
> we need to run a single binary and want to keep our disk image as
> small as possible. It will run inside a user-mode Qemu process.
> Reading through the nanobsd script it seems that it expects a raw disk
> for installation, so I do think using the nanobsd script itself well
> work well. Has anyone else done something similar? My goal is to
> have a disk image that is around 500MB.
>
> Thanks in advance!
> -pete
>
I wanted to close the loop on this discussion as I think I've found a
workable solution for my use-case. I'm using a three step process:
1) generate a raw disk image using "poudriere image". This phase
references a Jail I've built that has disabled lots of uneeded features
as per the docs here:
https://bsdrp.net/documentation/technical_docs/poudriere
2) next I use mkimg(1) to convert the raw disk image to a bootable qcow2
image that I can boot from Qemu. this results in a disk image that's
about 800MB.
3) the final phase is to use qemu-img to create a compressed qcow2
image. the resulting artifact of that process is a ~325MB Qcow2
diskimage that actually has decent performance (on my SSD backed zfs
filesystem).
I attempted to use poudriere image to generate a usb image directly, and
while that did work well sizing wise i ran into an issue where
insufficient inodes were allocated. I reference what I ran into in this
github issue:
https://github.com/freebsd/poudriere/issues/701
For me this current setup is fine for my purposes, although I'm sure
others can optimize this workflow a bit :)
Also, thanks again Allan and Dave Cottlehuber (who pinged me offlist)
for giving me some hints and pointing me in the right direction!
Cheers,
-pete
--
Pete Wright
pete at nomadlogic.org
@nomadlogicLA
More information about the freebsd-virtualization
mailing list