ZooKeeper 3.5 is trying to load an existing 3.4 data directory in which no snapshot
file is created. This usually happens if transaction count has not reached the limit of
snapshot creation. An extra startup check is introduced in 3.5.5 (ZOOKEEPER-2325) to
prevent a potential data inconsistency issue which makes ZooKeeper unable to start when
no snapshot files are present. It is a valid scenario in 3.4, but in 3.5 it will result
in failure to start ZooKeeper. For CDP 7.0.2+, you must set the property before the
upgrade and remove it after the upgrade is finished.
This fix allows you to specify a new configuration that will disable the
sanity check and allows ZooKeeper to start. You can set this configuration in two
ways, choose one of the following:
Adding a new system property for the ZooKeeper server:
-Dzookeeper.snapshot.trust.empty=true
You can also add this config to the zoo.cfg file, but in this case
you need to omit the "zookeeper." prefix and you need to add the
snapshot.trust.empty=true property to the
zoo.cfg file
