The old leader demotes lessor and all the leases' expire time will be
updated. Instead of returning incorrect remaining TTL, we should return
errors to force client retry.
Cherry-pick: d3bb6f688b4643155b4a9924cec726bdc76a1306
Signed-off-by: Wei Fu <fuweid89@gmail.com>
Backported PR #16822, commits f7e488dc9262685d6624755e0d3bb0a655863248,
67f17166bf2ba337dafb8e0ea8eea5f74a990767,
and f7ff898fd6c2d6dbb54278343073aa4fa5f46a03
Signed-off-by: Ivan Valdes <ivan@vald.es>
When etcdserver receives a LeaseRenew request, it may be still in
progress of processing the LeaseGrantRequest on exact the same
leaseID. Accordingly it may return a TTL=0 to client due to the
leaseID not found error. So the leader should wait for the appliedID
to be available before processing client requests.
To avoid inconsistant behavior during cluster upgrade we are feature
gating persistance behind cluster version. This should ensure that
all cluster members are upgraded to v3.6 before changing behavior.
To allow backporting this fix to v3.5 we are also introducing flag
--experimental-enable-lease-checkpoint-persist that will allow for
smooth upgrade in v3.5 clusters with this feature enabled.
Current checkpointing mechanism is buggy. New checkpoints for any lease
are scheduled only until the first leader change. Added fix for that
and a test that will check it.