[systemd-devel] How to use machinectl to get a running centos container?

Michal Sekletar msekleta at redhat.com
Fri Mar 10 09:38:02 UTC 2017

On Fri, Mar 3, 2017 at 4:09 PM, Lennart Poettering
<lennart at poettering.net> wrote:
> On Sat, 04.03.17 01:38, Daurnimator (quae at daurnimator.com) wrote:
>> On 3 March 2017 at 20:58, Lennart Poettering <mzerqung at 0pointer.de> wrote:
>> > On Fri, 03.03.17 12:34, Daurnimator (quae at daurnimator.com) wrote:
>> >
>> >> I'm trying to set up a centos 7 container with machinectl.
>> >> I've tried to run:
>> >>
>> >> machinectl pull-raw --verify=no
>> >> http://cloud.centos.org/centos/7/images/CentOS-7-x86_64-GenericCloud-1701.raw.tar.gz
>> >
>> > Hmm, what is a ".raw.tar.gz" file? That suffix makes no sense to me...
>> *shrugs* it's what I saw available for download from
>> http://cloud.centos.org/centos/7/images/
>> Apparently it's a gziped tar with a single file inside:
>> CentOS-7-x86_64-GenericCloud-20170131_01.raw
>> This .raw file is a disk image.
> That appears a bit redundant, and importd/machinectl pull-raw is not
> able to handle this.
>> > We support raw disk images and tarballs with OS trees in them, both
>> > compressed and non-compressed.
>> >
>> > There's currently a safety limit against overly large images enforced,
>> > of 8GiB. If the indicated image is larger than that, and that's
>> > intended we should probably bump this safety limit substantially (32G?
>> > 64G?), please file a github issue asking for this if this is the
>> > case. Or even better prep a PR, the fix is trivial:
>> >
>> > https://github.com/systemd/systemd/blob/master/src/import/pull-job.c#L530
>> Looks like it's *equal* to the limit.
>> Before I make a PR here, am I going about running a centos container
>> with machinectl the best way here?
>> How are other people doing this?
> I don't think many people are using CentOS caontainers with
> nspawn... That said, there's a good chance that it works OKish.

I use them regularly and they work just fine (well I use RHEL7 but
that should not matter). However I don't download images from
anywhere. I install distro trees to /var/lib/machines/ manually using

> Note that "machinectl pull-raw" is just a helper to make downloading
> easy. But if you have images in weird formats, you can download them
> and place them in /var/lib/machines (with the .raw suffix), and
> machined/nspawn is happy. It doesn't really matter how the image gets
> there as long as it gets there, and "machinectl pull-raw" is just one
> way.

That is what I also recommend. Installing from repo always worked for
me. For basic system container I just use example from nspawn manpage.


> Lennart
> --
> Lennart Poettering, Red Hat
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