ROLE

• Information of a master instance may include the following.
  • “master”
  • An integer that represents state of replication

• Information of a follower instance may include the following.
  • “follower”
  • Master IP address
  • Master IP port
  • Connection state that is either “disconnected”, “connecting”, “sync”, or “connected”
  • An integer that represents state of replication

• Information of a sentinel instance may include the following.
  • An array of master names.

1) "master"
2) 0
      2) "9200"
      3) "0"
   2) 1) "127.0.0.1"
      3) "0"