Tuesday, 18 September 2018

[Solved] How to install MySQL Server on CentOS 7?


Recently, when I am working on setting up MySQL Enterprise Server, I found, there is too much information available over internet and it was very difficult for a newbie to get what is needed for direct implementation. So, I decided to write a quick reference guide for setting up the server, covering end to end, starting from planning to production to maintenance. This is a first post in that direction, in this post, we will discuss about installing MySQL Enterprise Server on CentOS 7 machine. Note that, the steps are same for both the Enterprise and Community editions, only binary files are different, and downloaded from different repositories.

If you are looking for installing MySQL on Windows operating system, please visit this page https://www.rathishkumar.in/2016/01/how-to-install-mysql-server-on-windows.html. I am assuming, hardware and the Operating System is installed and configured as per the requirement. Let us begin with the installation.

Removing MariaDB:

The CentOS comes with MariaDB as a default database, if you try to install, MySQL on top of it, you will encounter an error message stating the MySQL library files conflict with MariaDB library files. Remove the MariaDB to avoid errors and to have a clean installation.  Use below statements to remove MariaDB completely:

sudo yum remove MariaDB-server
sudo yum remove MariaDB-client (This can be done in single step)
sudo rm –rf /var/lib/mysql
sudo rm /etc/my.cnf

(Run with sudo, if you are not logged in as Super Admin).

Downloading RPM files:

MySQL installation files (On CentOS 7 – rpm packages) can be downloaded from MySQL yum repository.

For MySQL Community Edition – there is clear and step-by-step guide available at the MySQL website - https://dev.mysql.com/doc/mysql-yum-repo-quick-guide/en/. The only step missing is downloading MySQL yum repository to your local machine. (This might looks very simple step, but most of the newbies, it is very helpful). 


For MySQL Enterprise Edition – the binary files can be downloaded from Oracle Software Delivery Cloud (http://edelivery.oracle.com) for latest version or previous versions visit My Oracle Support (https://support.oracle.com/).

As mentioned earlier, there is a clear and step-by-step guide available at the MySQL website for Community Edition, I will be continue with installing Enterprise Edition, steps are almost same.

Choosing the RPM file:

For MySQL Community Edition, all the RPM files will be included in the downloaded YUM repository, but for Enterprise Editions, these files will be downloaded separately. (For system administration purpose, all these files can be created under a MySQL repository).

For newbies, it may be confusing to understand, the different RPM files and its contents, I am concentrating on only files required for stand-alone MySQL instances. If there is requirement for embedded MySQL or if you working on developing plugins for MySQL, can install other files. It is completely depends on your requirement. The following tables, describe the required files and where to install.

RPM File
Description
Location
mysql-commercial-server-5.7.23-1.1.el7.x86_64.rpm
MySQL Server and related utilities to run and administer a MySQL server.
On Server
mysql-commercial-client-5.7.23-1.1.el7.x86_64.rpm
Standard MySQL clients and administration tools.
On Server & On Client
mysql-commercial-common-5.7.23-1.1.el7.x86_64.rpm
Common files needed by MySQL client library, MySQL database server, and MySQL embedded server.
On Server
mysql-commercial-libs-5.7.23-1.1.el7.x86_64.rpm
Shared libraries for MySQL Client applications
On Server

Installing MySQL:

Install the MySQL binary files in the following order, this is to avoid dependency errors, the following statements will install MySQL on local machine:

sudo yum localinstall mysql-commercial-libs-5.7.23-1.1.el7.x86_64.rpm
sudo yum localinstall mysql-commercial-client-5.7.23-1.1.el7.x86_64.rpm
sudo yum localinstall mysql-commercial-common-5.7.23-1.1.el7.x86_64.rpm
sudo yum localinstall mysql-commercial-server-5.7.23-1.1.el7.x86_64.rpm

Starting the MySQL Service:

On CentOS 7, the mysql service can be started by following:

sudo systemctl start mysqld.service
sudo systemctl status mysqld.service

Login to MySQL Server for first time:

Once the service is started, the superuser account ‘root’@’localhost’ created and temporary password is stored at the error log file (default /var/log/mysqld.log). The password can be retrieved by using the following command:

sudo grep 'temporary password' /var/log/mysqld.log

As soon as logged in to MySQL with the temporary password, need to reset the root password, until that, you cannot run any queries on MySQL server. You can reset the root account password by running below command.

mysql –u root –h localhost -p
alter user 'root'@'localhost' identified by 'NewPassword';

You can verify the MySQL status and edition by running the following commands, sample output provided below for MySQL 8.0 Community Edition (GPL License) running on Windows machine.

MySQL License Status
Notes:

MySQL conflicts with MariaDB: in case if there is conflict with MariaDB, you will see the error message as below:

file /usr/share/mysql/xxx from install of MySQL-server-xxx conflicts with file from package mariadb-libs-xxx

To resolve this error remove mariadb server and its related files from CentOS server. Refer the section - Removing mariadb.

Can’t connect to mysql server: MySQL server is installed but unable to connect from client.

Check this page for possible causes and solutions: https://www.rathishkumar.in/2017/08/solved-cannot-connect-to-mysql-server.html

Please let me know, if you are facing any other errors on comment section. I hope this post is helpful.