Hi,
I wanted to share with the community a very simple script I have written to synchronize my whitelisted domains between the two servers I have at home, two ways, with no need to have a master server. Just using SQL commands and the command "pihole -w".
The script can be found in my github page under the project named "pihole_sync":
https://github.com/manolonte/pihole_sync
Of course it can be improved a lot, for instance it does not synchronize regex domain entries, nor blacklisted domains, but was sufficient for my needs.
Regards,
Manuel