Subject: [alpine-devel] Using df with OverlayFS

From: Christian Kniep <[email-masked]>
Date: Fri, 2 Sep 2016 01:25:05 -0700

Hey there,

I am running an alpine container on a Linux system that uses overlay as
docker storage backend.

My suspicion would be, that the df command does not no how to deal with
overlay as a filesystem and therefore is shy providing output… :)

gentoo1 ~ # docker info |grep 'Storage Driver'
Storage Driver: overlay
gentoo1 ~ # docker run -ti --privileged alpine df -h
Filesystem                Size      Used Available Use% Mounted on
gentoo1 ~ # docker run -ti --privileged ubuntu df -h
Filesystem      Size  Used Avail Use% Mounted on
overlay         1.4T  3.6G  1.4T   1% /

If I run df on my Ubuntu16 reference box - using AUFS as a storage backend,
I get an output.

root@swarm0:~# docker info |grep 'Storage Driver'
WARNING: No swap limit support
Storage Driver: aufs
root@swarm0:~# docker run -ti alpine df -h
Filesystem                Size      Used Available Use% Mounted on
none                     77.2G     26.3G     47.0G  36% /

How do I get overlay into this little df command of mine? I guess somehow
fiddle around with the APKBUILD file of coreutils
<http://git.alpinelinux.org/cgit/aports/tree/main/coreutils/APKBUILD>…

Cheers
Christian

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From: Justin Cormack <[email-masked]>
Date: Thu, 8 Sep 2016 11:19:24 +0100

There is an issue already http://bugs.alpinelinux.org/issues/5703 and
this should be fixed shortly.

Justin

On 2 September 2016 at 09:25, Christian Kniep <[email-masked]> wrote:
> fiddle around with the APKBUILD file of coreutils…
>
> Cheers
> Christian
>
>
>
>

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From: Christian Kniep <[email-masked]>
Date: Thu, 8 Sep 2016 15:13:27 +0200

Hey Justin,

thanks for getting back to me. I have created a package on an overlay host
and using it as an workaround.
https://github.com/qnib/alpn-hadoop/blob/master/Dockerfile#L15-L16

But I am happy to get rid of it, once the issue is fixed. :)

Thanks
Christian

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From: Natanael Copa <[email-masked]>
Date: Thu, 8 Sep 2016 20:52:30 +0200

The problem was that line buffer in getmntent(3) in musl libc was too small.

I have sent a patch upstream:

http://www.openwall.com/lists/musl/2016/09/08/1

Once its reviewed I'll add it to Alpine.

-nc

On Thu, 8 Sep 2016 15:13:27 +0200
Christian Kniep <[email-masked]> wrote:

> > > overlay as a filesystem and therefore is shy providing output* :)
> > >
> > > fiddle around with the APKBUILD file of coreutils*
> > >
> > > Cheers
> > > Christian
> > >
> > >
> > >
> > >  
> >
> >
> > ---

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