we found a lease leak issue:
if a new member(by member add) is recovered by snapshot, and then
become leader, the lease will never expire afterwards. leader will
log the revoke failure caused by "invalid auth token", since the
token provider is not functional, and drops all generated token
from upper layer, which in this case, is the lease revoking
routine.
When clients have no permission to perform whatever operation, then
the applying may fail. We should also move consistent_index forward
in this case, otherwise the consitent_index may smaller than the
snapshot index.
When a user sets up a Mirror with a restricted user that doesn't have
access to the `foo` path, we will fail to get the most recent revision
due to permissions issues.
With this change, when a prefix is provided we will get the initial
revision from the prefix rather than /foo. This allows restricted users
to setup sync.
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.
This change is to ensure that all members returned during the client's
AutoSync are started and are not learners, which are not valid
etcd members to make requests to.
Previously the SetConsistentIndex() is called during the apply workflow,
but it's outside the db transaction. If a commit happens between SetConsistentIndex
and the following apply workflow, and etcd crashes for whatever reason right
after the commit, then etcd commits an incomplete transaction to db.
Eventually etcd runs into the data inconsistency issue.
In this commit, we move the SetConsistentIndex into a txPostLockHook, so
it will be executed inside the transaction lock.
Reason to store CI and term in backend was to make db fully independent
snapshot, it was never meant to interfere with apply logic. Skip of CI
was introduced for v2->v3 migration where we wanted to prevent it from
decreasing when replaying wal in
https://github.com/etcd-io/etcd/pull/5391. By mistake it was added to
apply flow during refactor in
https://github.com/etcd-io/etcd/pull/12855#commitcomment-70713670.
Consistency index and term should only be negotiated and used by raft to make
decisions. Their values should only driven by raft state machine and
backend should only be responsible for storing them.
