Redis did not provide a distributed solution for the worker, which
precluded several important planned functions. So instead, move to using
Zookeeper + PostgreSQL as the broker and result backend respectively.
Should be a seamless drop-in change but for future uses requires the
database host to be the primary coordinator IP rather than localhost, so
that writes can occur to the database from non-primary hosts.
Adds autobackup (integrated, managed VM backups with automatic remote
filesystem mounting, included backup expiry/removal and automatic
full/incremental selection, independent from the manual "pvc vm backup"
commands) to the CLI client.
This is a bit of a large command to handle only inside the CLI client,
but this was chosen as it's the only real place for it aside from an
external script.
There are several major restrictions on this command, mainly that it
must be run from the primary coordinator using the "local" connection,
and that it must be run as "root".
The command is designed to run in a cron/systemd timer installed by
pvc-ansible when the appropriate group_vars are enabled, and otherwise
not touched.
Also clean up the old versions in the postinst as they are obsolete and
not needed going forward. These only ever served as reference for a
manual installation which itself is long-obsoleted, and thus can be put
somewhere less "important".
This replicates some of the more important functionality of the defunct
pvc-flush.service unit. On presence of a trigger file (i.e.
/etc/pvc/autoready), it will trigger a "node ready" on boot. It does
nothing on shutdown as this must be handled by other mechanisms, though
a similar autoflush could be added as well.
This service caused more headaches than it was worth, so remove it.
The original goal was to cleanly flush nodes on shutdown and unflush
them on startup, but this is tightly controlled by Ansible playbooks at
this point, and this is something best left to the Administrator and
their particular situation anyways.
