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.
This reverts commit 65d14ccd92.
This was actually a bad idea. For inexplicable reasons, running these
Ceph commands manually (not even via Python, but in a normal shell)
takes 7 * two orders of magnitude longer than running them with the
Rados module, so long in fact that some basic commands like "ceph
health" would sometimes take longer than the 1 second timeout to
complete. The Rados commands would however take about 1ms instead.
Despite the occasional issues when monitors drop out, the Rados module
is clearly far superior to the shell commands for any moderately-loaded
Ceph cluster. We can look into solving timeouts another way (perhaps
with Processes instead of Threads) at a later time.
Rados module "ceph health":
b'{"checks":{},"status":"HEALTH_OK"}'
0.001204 (s)
b'{"checks":{},"status":"HEALTH_OK"}'
0.001258 (s)
Command "ceph health":
joshua@hv1.c.bonilan.net ~ $ time ceph health >/dev/null
real 0m0.772s
user 0m0.707s
sys 0m0.046s
joshua@hv1.c.bonilan.net ~ $ time ceph health >/dev/null
real 0m0.796s
user 0m0.728s
sys 0m0.054s
Joshua Boniface