The deprecated-key-path option is no longer handled, but it doesn't cause
problems because the key is explicitly ignored. It was completely removed in
Docker 19.03.0 [1].
As such, the option and the pre-start script to fix the corrupted key.json can
be removed now, as it has no effect, only printing confusing message when
Docker service fails to start.
[1] 98fc09128b
Prefer the containerd snapshotter by using it by default for new installs and
when no Docker data is present (e.g. after datadisk wipe). The snapshotter is
enabled by a dockerd flag which is set when a flag file is present in the data
partition. This flag file can be used also to opt-in for this snapshotter on
legacy installs (high level API through OS Agent and Supervisor TBD), to
migrate to the containerd snapshotter this file can be simply created manually.
Testing shown no major problems when migrating, the old overlay2 folder can be
(and should be - to avoid situations where the data disk might run out of
space) deleted before the docker.service is started in the docker-prepare
script.
Note that there's no offline migration path, OS needs to be connected to the
internet to re-download the images when migrating. This could be theoretically
possible through docker image save/load functions but guarding for enough of
space and other edge cases would be probably too complex to justify it.
Refs #4252
Refs #4253 - easier opt-in method is still needed
Closes#4254 - migration is handled seamlessly by Docker
* Relocate HAOS Systemd drop-ins to /usr/lib/systemd
With some exceptions, Systemd drop-ins overriding default unit configuration
have been placed to `/etc/systemd/system`. This is meant for user overrides of
those, or per `man 5 systemd.unit` for "system unites created by the
administrator". Relocate all of these to `/usr/lib/systemd` which should be
used as path for units "installed by the distribution package manager" which is
closer to what we're trying to achieve.
This will make it easier to detect changes to unit files once we enable the
possibility to edit the content of /etc.
* Patch systemd-timesyncd.service instead of replacing it fully
