Custom Qcow2 Images
Emmanuel Vadot
manu at bidouilliste.com
Fri Jul 19 10:43:55 UTC 2019
Hi Pete,
On Thu, 18 Jul 2019 19:53:42 -0700
Pete Wright <pete at nomadlogic.org> wrote:
>
> 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
This is a problem with makefs, I don't recall the details but even
when using -f to ensure that a minimum of free inode were present I had
problems, I'll try to find my notes on this.
Using rawdisk this uses mdconfig/newfs so you don't have inodes
problems.
> For me this current setup is fine for my purposes, although I'm sure
> others can optimize this workflow a bit :)
I won't be against you adding qcow2 support in poudriere image :)
> 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
>
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--
Emmanuel Vadot <manu at bidouilliste.com> <manu at freebsd.org>
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