We have two different running redis clusters and we want to migrate one to another. Both of them are serving and down time is not allowed.
Is there a recommended solution for the migration of redis?
You can basically just make one instance the slave of the other temporarily, and it will migrate all data for you. https://groups.google.com/forum/m/#!topic/redis-db/KOhA-TD1V6U
Or if you are wanting to just move some keys, the migrate/move command will allow you to move values per key, which you could iterate over to move many.