On a replication master, you must enable binary logging and establish a unique server ID. If this has not already been done, this part of master setup requires a server restart.
Binary logging must be enabled on the master because the binary log is the basis for sending data changes from the master to its slaves. If binary logging is not enabled, replication will not be possible.
Each server within a replication group must be configured with a unique server ID. This ID is used to identify individual servers within the group, and must be a positive integer between 1 and (232)–1. How you organize and select the numbers is entirely up to you.
To configure the binary log and server ID options, you will need
to shut down your MySQL server and edit the
my.cnf or my.ini file.
Add the following options to the configuration file within the
[mysqld] section. If these options already
exist, but are commented out, uncomment the options and alter
them according to your needs. For example, to enable binary
logging using a log file name prefix of
mysql-bin, and configure a server ID of 1,
use these lines:
[mysqld] log-bin=mysql-bin server-id=1
After making the changes, restart the server.
If you omit server-id (or set
it explicitly to its default value of 0), a master refuses
connections from all slaves.
For the greatest possible durability and consistency in a
replication setup using InnoDB with
transactions, you should use
innodb_flush_log_at_trx_commit=1 and
sync_binlog=1 in the master
my.cnf file.
Ensure that the skip-networking
option is not enabled on your replication master. If
networking has been disabled, your slave will not able to
communicate with the master and replication will fail.