Selinux

Modern Linux Systems have a mechanism called logrotate to rotate different log files.

The general configuration file is located under /etc/logrotate.conf and specific changes are under /etc/logrotate.d/

By default the logrotate job is started once a day by a O/S cron.daily job: /etc/cron.daily/logrotate

Because the default log rotation configuration does not exactly what I want I have adapted it a bit:

First I need a database user for log rotation:

CREATE USER 'logrotate'@'localhost' IDENTIFIED BY 'secret'; …

What is SELinux?

The Security-Enhanced Linux is an extension to the Linux Kernel, made by the NSA (National Security Agency). It implements Mandatory Access Controls (MAC), which allow an administrator to define, how applications and users can access resources on a system.

There is more detail in the SELinux Wki: https://selinuxproject.org/page/FAQ
… and the CentOS documentation: https://wiki.centos.org/HowTos/SELinux

Some distributions have it installed by default, but not active, some have it …

Maybe you experienced some strange behaviour with MySQL: Everything is installed correctly and should work. But it does not.

Symptoms we have seen:

• MySQL starts/stops properly when started/stopped with service mysqld restart but MySQL does not start when a server is rebooted.
• Or after upgrading MySQL binaries mysqld will not start at all any more.
• Or after relocating MySQL datadir or changing default port MySQL does not start any more.

shell> service mysqld start
MySQL Daemon failed to start.
Starting …