REPLICAOF host port
Time complexity: O(1)
REPLICAOF command can change the replication settings of a replica on the fly.
If a Dragonfly server is already acting as replica, the command
REPLICAOF NO ONE will turn off the replication, turning the Dragonfly server into a MASTER. In the proper form
REPLICAOF hostname port will make the server a replica of another server listening at the specified hostname and port.
If a server is already a replica of some master,
REPLICAOF hostname port will stop the replication against the old server and start the synchronization against the new one, discarding the old dataset.
REPLICAOF NO ONE will stop replication, turning the server into a MASTER, but will not discard the replication. So, if the old master stops working, it is possible to turn the replica into a master and set the application to use this new master in read/write. Later when the other Dragonfly server is fixed, it can be reconfigured to work as a replica.
dragonfly> REPLICAOF NO ONE
dragonfly> REPLICAOF 127.0.0.1 6799
masterauth- the credentials for accessing authenticated master server