Starting Multiple Instances in MySQL

We can start multiple MySQL instance in the same server by running them in different ports.
To configure multiple instances,

1. add the below entries in /etc/my.cnf
[mysqld@replica01]
datadir=/var/lib/mysql-replica01
socket=/var/lib/mysql-replica01/mysql.sock
port=3307
log-error=/var/log/mysqld-replica01.log
[mysqld@replica02]
datadir=/var/lib/mysql-replica02
socket=/var/lib/mysql-replica02/mysql.sock
port=3308
log-error=/var/log/mysqld-replica02.log

2.Start both instances separately as below
systemctl start mysqld@replica01
systemctl start mysqld@replica02

3.To start all the instances together we can use wildcard
systemctl start mysqld@replica*

4.To login to the mysql instances separately we can use the specific socket file for the instance
mysql -u root -p -S /var/lib/mysql-replica01/mysql.sock
mysql -u root -p -S /var/lib/mysql-replica02/mysql.sock