Waiting for the daemons to stop took too much time on some nodes and
could throw off the lockstep. Instead, leverage background=True to run
the systemctl os_commands in the background (when they complete is
irrelevant), stop the Metadata API first, and don't delay during its
stop at all.
Previously VMs in stop/shutdown/restart states wouldn't be properly
handled during a node flush. This fixes the bugs and ensures that the
transient VM states (shutdown/restart) are completed before proceeding,
and then avoids setting a stopped/shutdown VM to shutdown/auotstart.
This branch commit refactors the pvcnoded component to better adhere to
good programming practices. The previous Daemon.py was a massive file
which contained almost 2000 lines of direct, root-level code which was
directly imported. Not only was this poor practice, but this resulted
in a nigh-unmaintainable file which was hard even for me to understand.
This refactoring splits a large section of the code from Daemon.py into
separate small modules and functions in the `util/` directory. This will
hopefully make most of the functionality easy to find and modify without
having to dig through a single large file.
Further the existing subcomponents have been moved to the `objects/`
directory which clearly separates them.
Finally, the Daemon.py code has mostly been moved into a function,
`entrypoint()`, which is then called from the `pvcnoded.py` stub.
An additional item is that most format strings have been replaced by
f-strings to make use of the Python 3.6 features in Daemon.py and the
utility files.
Joshua Boniface