op-guide/v2-migration: endpoint hashkv post migration
@@ -38,6 +38,10 @@ Second, migrate the v2 keys into v3 with the [migrate][migrate_command] (`ETCDCT
Restart the etcd members and everything should just work.
+For etcd v3.3+, run `ETCDCTL_API=3 etcdctl endpoint hashkv --cluster` to ensure key-value stores are consistent post migration.
+
+**Warn**: When v2 store has expiring TTL keys and migrate command intends to preserve TTLs, migration may be inconsistent with the last committed v2 state when run on any member with a raft index less than the last leader's raft index.
+
### Online migration
If the application cannot tolerate any downtime, then it must migrate online. The implementation of online migration will vary from application to application but the overall idea is the same.
