docker: exec format error

[Scott Moser]

On Fri, 26 Jun 2015, Pierre-Andre Morey wrote:

> Not so easy, as the image need to support multiple arch, there is no direct
> ubuntu:trusty to armbuild/ubuntu:trusty, it could also be kickinz1/ubuntu.
>
> Docker afaik only support amd64 arch for now. Ubuntu support more arch and
> has docker working in those, but the docker-registry doesn't build official
> images on those arch yet.
>
> So do we want to have the snappy docker wrapper to explicitly modify
> 'ubuntu' string to 'armbuild/ubuntu' on snappy arm arches?
>
> We might want some sort of 'official' arch repository for supported arch
> (armhf, amd64, ppc, ppc64el, arm64).

This could be made to work, but it would mean Canonical/Ubuntu publishing
images as 'user' images where as right now the ubuntu images show up as
'official'.

Example:
$ docker image search
$ docker search ubuntu | head -n 4
NAME             DESCRIPTION                                     STARS  OFFICIAL AUTOMATED
ubuntu           Ubuntu is a Debian-based Linux operating s...   1852   [OK]
ubuntu-upstart   Upstart is an event-based replacement for ...   27     [OK]
tutum/ubuntu     Ubuntu image with SSH access. For the root...   25              [OK]

Right now we are 'ubuntu' without a leading user (like 'tutum/ubuntu')

If we did this, we'd no longer get:
 docker pull ubuntu
we'd need:
 docker pull canonical/ubuntu
or
 docker pull ubuntu/ubuntu

And then to fix arch our only path would be to add '-<arch>'
 docker pull ubuntu/ubuntu-amd64

Its much less pretty.

We really need to work with upstream to do this cleanly, and anything else is
going to be a brittle hack that we'd need to maintain, and would only work for
a very small set of things.

Ie, we could in fact make:
 docker run -t ubuntu
But doing much more would be hard.  Additionally, we dont even really *have* an
official arm64 ubuntu anywhere that we could translate to.



>
> 2015-06-25 18:26 GMT+02:00 Dustin Kirkland <kirkland at canonical.com>:
>
> > On Thu, Jun 25, 2015 at 8:59 AM, Jamie Strandboge <jamie at canonical.com>
> > wrote:
> > > On 06/25/2015 01:25 AM, Seth Arnold wrote:
> > >> On Wed, Jun 24, 2015 at 05:40:27PM -0700, Zhuoqun Cheng wrote:
> > >>> *$ docker run hello-world*
> > >>> *FATA[0001] Error response from daemon: Cannot start container
> > >>> abcbe08d0619fef08b9de12dfab982ff747ac47198c185899410676f35b512e2: [8]
> > >>> System error: exec format error *
> > >>> (Just to be clear, the first time I ran it, it did pull the image.)
> > >>
> > >> "exec format error" sounds a lot like an architecture mis-match. Are you
> > >> sure the image you downloaded is inteded to be used on ARM? Is it
> > compiled
> > >> for the correct arm instruction set?
> > >>
> > > FYI, if using docker on arm you need to use '-t armbuild/ubuntu:trusty'
> > instead
> > > of '-t ubuntu:trusty'.
> >
> > Can we please patch docker to detect and handle that automatically?
> >
> > Thanks,
> > Dustin
> >
>