MYSQL CENTOS 7
wget http://repo.mysql.com/mysql-community-release-el7-5.noarch.rpm
rpm -ivh mysql-community-release-el7-5.noarch.rpm
yum update
yum install mysql-server
systemctl start mysqld
[root@clusterserver1 ~]# systemctl start mysqld
[root@clusterserver1 ~]# systemctl enable mysqld
[root@clusterserver1 ~]# systemctl status mysqld
[root@clusterserver1 ~]# mysql_secure_installation
NOTE: RUNNING ALL PARTS OF THIS SCRIPT IS RECOMMENDED FOR ALL MySQL
SERVERS IN PRODUCTION USE! PLEASE READ EACH STEP CAREFULLY!
In order to log into MySQL to secure it, we’ll need the current
password for the root user. If you’ve just installed MySQL, and
you haven’t set the root password yet, the password will be blank,
so you should just press enter here.
Enter current password for root (enter for none):
OK, successfully used password, moving on…
Setting the root password ensures that nobody can log into the MySQL
root user without the proper authorisation.
Set root password? [Y/n] y
New password:
Re-enter new password:
Password updated successfully!
Reloading privilege tables..
… Success!
By default, a MySQL installation has an anonymous user, allowing anyone
to log into MySQL without having to have a user account created for
them. This is intended only for testing, and to make the installation
go a bit smoother. You should remove them before moving into a
production environment.
Remove anonymous users? [Y/n] y
… Success!
Normally, root should only be allowed to connect from ‘localhost’. This
ensures that someone cannot guess at the root password from the network.
Disallow root login remotely? [Y/n] y
… Success!
By default, MySQL comes with a database named ‘test’ that anyone can
access. This is also intended only for testing, and should be removed
before moving into a production environment.
Remove test database and access to it? [Y/n] y
– Dropping test database…
ERROR 1008 (HY000) at line 1: Can’t drop database ‘test’; database doesn’t exist
… Failed! Not critical, keep moving…
– Removing privileges on test database…
… Success!
Reloading the privilege tables will ensure that all changes made so far
will take effect immediately.
Reload privilege tables now? [Y/n] y
… Success!
All done! If you’ve completed all of the above steps, your MySQL
installation should now be secure.
Thanks for using MySQL!
Cleaning up…
[root@clusterserver1 ~]# systemctl restart mysqld
[root@clusterserver1 ~]# mysql -u root -p
Enter password:
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 2
Server version: 5.6.33 MySQL Community Server (GPL)
Copyright (c) 2000, 2016, Oracle and/or its affiliates. All rights reserved.
Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.
Type ‘help;’ or ‘\h’ for help. Type ‘\c’ to clear the current input statement.
mysql>
create database testdb;
create user ‘testuser’@’localhost’ identified by ‘password’;
grant all on testdb.* to ‘testuser’ identified by ‘password’;
mysql> create database testdb;
Query OK, 1 row affected (0.00 sec)
mysql> create user ‘testuser’@’localhost’ identified by ‘password’;
Query OK, 0 rows affected (0.00 sec)
mysql> grant all on testdb.* to ‘testuser’ identified by ‘password’;
Query OK, 0 rows affected (0.00 sec)
mysql>
create database testdb;
grant all on testdb.* to ‘testuser’ identified by ‘password’;
mysql -u testuser -p
use testdb;
create table customers (customer_id INT NOT NULL AUTO_INCREMENT PRIMARY KEY, first_name TEXT, last_name TEXT);
[root@clusterserver1 ~]# mysql -u testuser -p
Enter password:
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 4
Server version: 5.6.33 MySQL Community Server (GPL)
Copyright (c) 2000, 2016, Oracle and/or its affiliates. All rights reserved.
Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.
Type ‘help;’ or ‘\h’ for help. Type ‘\c’ to clear the current input statement.
mysql> use testdb;
Database changed
mysql> create table customers (customer_id INT NOT NULL AUTO_INCREMENT PRIMARY KEY, first_name TEXT, last_name TEXT);
Query OK, 0 rows affected (0.01 sec)
mysql>
Reset the MySQL Root Password
If you forget your root MySQL password, it can be reset.
Stop the current MySQL server instance, then restart it with an option to not ask for a password.
systemctl stop mysqld
mysqld_safe –skip-grant-tables &
Reconnect to the MySQL server with the MySQL root account.
mysql -u root
Use the following commands to reset root’s password. Replace password with a strong password.
use mysql;
update user SET PASSWORD=PASSWORD(“password”) WHERE USER=’root’;
flush privileges;
exit
Then restart MySQL.
systemctl start mysqld
Tune MySQL
MySQL Tuner is a Perl script that connects to a running instance of MySQL and provides configuration recommendations based on workload. Ideally, the MySQL instance should have been operating for at least 24 hours before running the tuner. The longer the instance has been running, the better advice MySQL Tuner will give.
Download MySQL Tuner to your home directory.
wget https://raw.githubusercontent.com/major/MySQLTuner-perl/master/mysqltuner.pl
To run it:
perl ./mysqltuner.pl
You will be asked for the MySQL root user’s name and password. The output will show two areas of interest: General recommendations and Variables to adjust.
MySQL Tuner is an excellent starting point to optimize a MySQL server but it would be prudent to perform additional research for configurations tailored to the application(s) utilizing MySQL on
recently upgraded my development laptop to CentOS 7 and while I was at it built a spare laptop running the same operating system. After manually creating a dozen MySQL databases and users and then importing their data from dump files on one laptop, I wasn’t interested in going through exactly the same process again on the second laptop.
As is now the default on CentOS 7, the databases were actually MariaDB (a community-developed fork of MySQL) rather than MySQL, but that’s not relevant here. The following procedure describes how I migrated an entire MariaDB/MySQL RDBMS installation in one go without recreating any databases or users or dumping and re-importing any files. The same procedure would of course work for migrating similar data between CentOS 7 servers.
Before proceeding I should emphasise that this data migration was between two machines with identical freshly installed operating systems. In cases where the operating systems, distributions or version were different things might not go so smoothly. One concern would be that global database configuration parameters on both machines were compatible.
Original Database Server
1: Create a directory to hold the data being migrated:
# mkdir mariadbdata
2: Stop the MariaDB/MySQL server:
# systemctl stop mariadb
3: Copy contents of /var/lib/mysql to the directory just created:
# cp -r /var/lib/mysql/* mariadbdata
4: Restart the MariaDB/MySQL server again:
# systemctl start mariadb
5: Compress the data:
# tar -czvf mariadbdata.tar.gz mariadbdata
6: Copy the compressed file to new server.
New Database Server
1: Install MariaDB but don’t start it yet.
2: Uncompress data file:
# tar -xzvf mariadbdata.tar.gz
3: Move contents of data directory to /var/lib/mysql:
# mv mariadbdata/* /var/lib/data
4: Change ownership of all files in /var/lib/mysql to mysql user:
# chown -R mysql.mysql /var/lib/mysql/*
5: Restore correct SELinux security contexts:
# restorecon -R /var/lib/mysql/
6: Enable and start MariaDB:
# systemctl enable mariadb # systemctl start mariadb
Typically the mysql database are located in /var/lib/mysql
I want to change it to /var/data/mysql
Modify the paths as required in the below commands
stop mysql
systemctl stop mysqld.service
create new mysql data directory
mkdir /var/data/mysql
modify /etc/my.cnf and point to new data directory – add the client section to the top
[client] port=3306 socket=/var/data/mysql/mysql.sock [mysqld] datadir=/var/data/mysql socket=/var/data/mysql/mysql.sock
copy all files from /var/lib/mysql to the new directory /var/data/mysql
cp -r /var/lib/mysql/* /var/data/mysql
permissions for the new directory
chown -R mysql /var/data/mysql; chgrp -R mysql /var/data/mysql; chmod -R g+rw /var/data/mysql;
also modify SELINUX settings to allow mysql to use the different path
# add context and make it permanent semanage fcontext -a -s system_u -t mysqld_db_t "/var/data/mysql(/.*)?" restorecon -Rv /var/data/mysql
start mysql
systemctl start mysqld.service
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