This is a proof-of-concept for RPM package layering on top of an OSTree base tree. It is only a demonstrator; do not use in production.
To use:
# ./atomic-pkglayer add strace
Now, let's try:
# ostree admin status
What's up with that ? Well, OSTree is telling us
it no longer knows how to upgrade the system. If you look at the
origin file underneath /ostree/deploy/.../*.origin for the new
deployment, you'll see that we have listed the additional packages,
and the refspec is now base_refspec.
And indeed if we try it:
# atomic upgrade
error: No origin/refspec in current deployment origin; cannot upgrade via ostree
Anyways, let's reboot, and notice that strace is available.
# systemctl reboot
# rpm -q strace
A very important thing to note; we do have a single unified RPM database, still in /usr/share/rpm.
# ./atomic-pkglayer upgrade
This will check for both tree upgrades and new packages. Oh, and it will redownload the packages every time. Because, again, this is just a proof of concept...
# ./atomic-pkglayer remove strace
Unlike most package systems, this can only be used to remove explicitly added packages. It's not allowed to remove packages from the base tree, nor packages that are intermediate dependencies of added packages.
There are a number of reasons I wrote this proof-of-concept as an addon layer.
- The whole subject deserves a lot of thought and careful coding, and ultimately will require changes in RPM to make this work more widely.
- There's a strong drive right now to backport rpm-ostree to EL7, and that limits the dependency/feature growth.
- For rpm-ostree, we intend to use the new C libraries of hawkey/librepo for package management - this will allow much tighter integeration than using yum allows.
- yum is GPL, rpm-ostree is LGPL (for several reasons, but an important one is to allow ASL2.0 code to link to it)