prepare method preserves data always from CONF.mount_point, which is not a valid case.
Referring to the code at
https://github.com/openstack/trove/blob/master/trove/guestagent/datastore/mysql/manager.py#L119-L121
1. The data would always exist on /var/lib/mysql ir-respective of value of CONF.mount_point, because that is the location where mysql puts its data when installed.
2. We should be preserving /var/lib/mysql instead of CONF.mount_point.
3. Currently, CONF.mount_point has the value "/var/lib/mysql" but if some one needs a changes in CONF.mount_point, then prepare would not backup the data directories, in fact that may backup nothing because CONF.mount_point might not be an existing location.
4. Going forward, there are two ways to use this value /var/lib/mysql in the code, either like https://github.com/openstack/trove/blob/master/trove/guestagent/datastore/mysql/service.py#L50 to hard code a variable, and other way would be to use a CONF parameter. I think we should prefer the CONF way, so that this parameter would be modifiable later to other value by changing configuration files instead of change in code.
Fix proposed to branch: master
Review: https:/