Syntax:
SHOW SLAVE HOSTS

Displays a list of replication slaves currently registered with the
master.

SHOW SLAVE HOSTS should be executed on a server that acts as a
replication master. SHOW SLAVE HOSTS requires the REPLICATION SLAVE
privilege. The statement displays information about servers that are or
have been connected as replication slaves, with each row of the result
corresponding to one slave server, as shown here:

mysql> SHOW SLAVE HOSTS;
+------------+-----------+------+-----------+--------------------------------------+
| Server_id  | Host      | Port | Master_id | Slave_UUID                           |
+------------+-----------+------+-----------+--------------------------------------+
|  192168010 | iconnect2 | 3306 | 192168011 | 14cb6624-7f93-11e0-b2c0-c80aa9429562 |
| 1921680101 | athena    | 3306 | 192168011 | 07af4990-f41f-11df-a566-7ac56fdaf645 |
+------------+-----------+------+-----------+--------------------------------------+

o Server_id: The unique server ID of the slave server, as configured in
  the slave server's option file, or on the command line with
  --server-id=value.

o Host: The host name of the slave server as specified on the slave
  with the --report-host option. This can differ from the machine name
  as configured in the operating system.

o User: The slave server user name as, specified on the slave with the
  --report-user option. Statement output includes this column only if
  the master server is started with the --show-slave-auth-info option.

o Password: The slave server password as, specified on the slave with
  the --report-password option. Statement output includes this column
  only if the master server is started with the --show-slave-auth-info
  option.

o Port: The port on the master to which the slave server is listening,
  as specified on the slave with the --report-port option.

  A zero in this column means that the slave port (--report-port) was
  not set.

o Master_id: The unique server ID of the master server that the slave
  server is replicating from. This is the server ID of the server on
  which SHOW SLAVE HOSTS is executed, so this same value is listed for
  each row in the result.

o Slave_UUID: The globally unique ID of this slave, as generated on the
  slave and found in the slave's auto.cnf file.

URL: https://dev.mysql.com/doc/refman/5.7/en/show-slave-hosts.html

