[colinwalters]

Right, this is a pretty good summary (that docker is 1 level above).

One fundamental difference is that OSTree has a custom serialization format for trees (inspired by git), whereas from what I can tell from the code, docker is just tar (I assume whatever the host /usr/bin/tar serializes to). For example, OSTree explicitly supports extended attributes, so it can support SELinux (and SMACK). Fedora ships a patched tar but...the tar format is a really serious mess.

I would further add though that OSTree does, providing the OS is compatible with it, allow booting a separate "deployment" as a container. So for example if you have Debian in /ostree/deploy/debian/90cd266 while you're booted into /ostree/deploy/fedora/562d0a, you can easily just systemd-nspawn /ostree/deploy/debian/90cd266 and boot the same OS as a container.

But the emphasis right now of OSTree is indeed on bare metal deployments, and I'd like to push hard to integrate with package systems.

[shykes]

> you can easily just systemd-nspawn /ostree/deploy/debian/90cd266 and boot the same OS as a container

Perhaps we should be looking at integrating ostree and docker then? :)

> I'd like to push hard to integrate with package systems.

How would that integration work exactly?

[colinwalters]

> Perhaps we should be looking at integrating ostree and docker then? :)

It might make sense for docker to be able to store containers as OSTree commits in addition to tarfiles. But I haven't used it myself. On the HTTP side, OSTree may be less efficient or more efficient than what docker does on the wire for updates; I don't know. Static deltas will help significantly.

> How would that integration work exactly?

This section describes it very briefly: https://people.gnome.org/~walters/ostree/doc/adapting-packag...

Basically this is something you can do on a build server or on a client.