Running Multiple Instances of MySQL in CentOS/Fedora/RedHat Linux


              Running Multiple Instances of MySQL in CentOS/Fedora/RedHat Linux

                       1. Make sure that you have installed mysql-server in your Linux , If not install it with
yum install –y mysql-server
              2After installing MySQL-Server , Open your terminal and paste as 
  
                        mkdir /var/lib/mysql2
chown -R mysql.mysql /var/lib/mysql2
mkdir /var/log/mysql2         
chown -R mysql.mysql /var/log/mysql2
Above code stands for creating two directories for MySQL 2nd instance , There /var/lib/mysql2  for data directory and /var/log/mysql2 is for log directory. After that changing the owner as mysql for both.
              3. Make a dump of mycnf configuration file with 
 
 cp -R /etc/my.cnf /etc/my2.cnf

                    Then Open it with

nano /etc/my2.cnf  (or ) vim /etc/my2.cnf
                     Make the changes as mentioned in the below file.
                                     # change/add the following options
                                    port = 3307     #different port
                                    datadir = /var/lib/mysql2       #diff data dir
                                    socket =  /var/lib/mysql2/mysql2.sock           # diff socket path
                                    # add [mysql_safe]
                                    log-error = /var/log/mysql2/mysql.log # diff log
                                    pid-file = /var/lib/mysql2/mysql2.pid            #diff PI
 Then save & close it.
                            4.  Now in the terminal paste these lines after one , with success of each command
mysql_install_db –user=mysql –datadir=/var/lib/mysql2/
mysqld_safe –defaults-file=/etc/my2.cnf &
mysqladmin -S  /var/lib/mysql2/mysql2.sock -u root password ‘newpass’
mysql -S  /var/lib/mysql2/mysql2.sock -u root -p
5                 5. That will start your MySQL 2ndinstance and you can check it with 
netstat -nptelu | grep my
netstat -l | grep my
6                6. If you want to shutdown that instance then you can do it with
mysqladmin -S  /var/lib/mysql2/mysql2.sock -u root -p shutdown
               
               
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CentOS – IP Setting – Static IP- Command Line

Commands required to set a static IP in CentOS  are

. In Terminal , turn into root user and type as

vi /etc/sysconfig/network-scripts/ifcfg-eth0

There Place the content as

There as you can see the parameter. Set similar in your PC.Then save & close it with + + + .

Then In terminal type as

vi /etc/sysconfig/network

There give your Gateway as shown

You can disable/Enable network from there.

Then check your Gateway updated or not with

route -n

Then after that restart your network with

service network restart

Thats it. Now you can connect to your CentOS to Internet.
Points to remember : Nothing much !! all you have to execute the commands as root user.