[openstack-dev] [glance][ironic][cinder][nova] 'tar' as an image disk_format

Brian Rosmaita brian.rosmaita at RACKSPACE.COM
Thu Feb 4 15:13:19 UTC 2016


The discussion went in two directions:

(1) Whether supporting OS tarballs in Ironic is a good idea ... continuing
discussion on the Ironic spec, https://review.openstack.org/#/c/248968/

(2) How an OS tarball should be identified in Glance ... continuing
discussion on the Glance spec-lite,

If you have an opinion, please leave a comment in the appropriate place.


On 1/23/16, 9:54 AM, "Brian Rosmaita" <brian.rosmaita at RACKSPACE.COM> wrote:

>Please provide feedback about a proposal to add 'tar' as a new Glance
>The Ironic team is adding support for "OS tarball images" in Mitaka.
>This is a compressed tar archive of a / (root filesystem). These tarballs
>are created by first installing the OS packages in a chroot and then
>compressing the chroot as tar.*.  The proposal
> is to store such images as disk_format == tar and container_format ==
>Intuitively, 'tar' seems more like a container_format.  The Glance
>developer documentation, however, says that "The container format refers
>to whether the virtual machine image is in a file format that also
>contains metadata about the actual virtual machine."[1]
>  Under this proposal, there is no such metadata included.
>The Glance docs say this about disk_format: "The disk format of a virtual
>machine image is the format of the underlying disk image. Virtual
>appliance vendors have different formats for laying out the information
>contained in a virtual machine disk image."[1]
>  Under this definition, 'tar' as used in this proposal [0] does in fact
>seem to be a disk_format.
>There is not currently a 'tar' container format defined for Glance.  The
>closest we have now is 'ova' (an OVA tar archive file) and 'docker' (a
>Docker tar archive of the container filesystem).  And, in fact, 'tar' as
>a container format wouldn't be very
> helpful, as it doesn't indicate where in the tarball the metadata should
>be found.
>The goal here is to come up with an identifier for an "OS tarball image"
>that's acceptable across projects and isn't confusing for people who are
>creating images.
>Thanks in advance for your feedback,
>[0] https://bugs.launchpad.net/glance/+bug/1535900
>[1] https://github.com/openstack/glance/blob/master/doc/source/formats.rst

More information about the OpenStack-dev mailing list