On 8/16/23 14:52, Simon Horman wrote: > On Tue, Jul 18, 2023 at 02:38:26AM -0700, Han Zhou wrote: >> When a server becomes unstable due to system overloading or intermittent >> partitioning, it may miss some heartbeats and then starts election with >> a new term, which would disrupt the otherwise healthy cluster formed by >> the rest of the healthy nodes. Such situation may exist for a long time >> until the "flapping" server is shutdown or recovered completely, which >> can severely impact the availability of the cluster. The pre-vote >> mechanism introduced in the raft paper section 9.6 can prevent such >> problems. This patch implements the pre-vote mechanism. >> >> Note: during the upgrade, since the old version doesn't recognize the >> new optional field in the vote rpc (and the ovsdb_parse_finish validates >> that all fields in the jsonrpc are parsed), an error log may be noticed >> on old nodes if an upgraded node happens to become candidate first and >> vote for itself, and the vote request will be discarded. If this happens >> before enough nodes complete the upgrade, the vote from the upgraded >> node may not reach the quorum. This results in re-election, and any old >> nodes should be able to vote and get elected as leader. So, in unlucky >> cases there can be more leader elections happening during the upgrade. >> >> Signed-off-by: Han Zhou <[email protected]> > > Reviewed-by: Simon Horman <[email protected]> >
Thanks, Han and Simon! I wrapped a few long lines in the test and applied the change. Best regards, Ilya Maximets. _______________________________________________ dev mailing list [email protected] https://mail.openvswitch.org/mailman/listinfo/ovs-dev
