On 12.01.2014 22:34, Alek Paunov wrote:
So, finally on that road we have:
...
- NTH: remote SCC DB for the instance,
- NTH: SCC local state for multiple instances (e.g. deployment nodes or
local containers) kept in the same SCC DB
- NTH: SCC local state inheritance between instances
Another closely related topic is the system snapshotting or in other
words - system "flavors" variants/subvariants tree.
Even before the btrfs magic, we have at hand wonderful snapshot
mechanisms - LVM, qcow2+qemu-nbd-connect, ceph rbd, etc. Probably, LVM
thinp currently is the best for the purpose of supporting tree of system
variants.
Once we apply FS snapshotting, combined with the SCC NTHs above, there
are at least two appealing use-cases:
- reusing one base e.g. F20 server container image for both the host and
the incompatible containers (e.g. when one application requires nodejs
0.8 and another nodejs 0.10)
- easy testbed for resolving the upgrade path for an existing, possibly
non "pure Fedora" server with care about the deployed services.