When the docker packages are installed, the services and related docker0 network interface are enabled. In some cases, you may want to disable the docker service and the docker0 network interface as well. This post details how to disable Docker and the docker0 interface if it is not required or if the docker0 interface is […]
Archives for October 2019
How To Reset MySQL 8.0 Root Password On Windows
If you set a root password previously but have forgotten what it was, you can set a new password. The following procedure is for Windows systems. You must be logged in to Windows as a user with administrative privileges, then follow these steps: 1. Stop the MySQL server if it is running. For a server […]
What is the purpose of “system user” in MySQL Replication
This post focusses on understanding why the “system user” is seen in SHOW PROCESSLIST and the information_schema.PROCESSLIST view on replication slaves. The system user is not a real user and is used for display purposes only to indicate it is the system performing the task. It is used by the I/O and SQL threads (connection […]
What are Reserved User Accounts in MySQL
The are a few users created by MySQL for various purposes ranging from handling the replication to be the definer for sys schema objects. The users are summarized in the following table: User First Version Last Version Feature Comments system user (At least since 5.0) Replication Used for the I/O and SQL threads (connection […]
What is the purpose of “mysql.sys@localhost” user
This post explains why the mysql.sys@localhost user exists and what it is used for. The mysql.sys@localhost user is a system user used as the definer for view, procedures, and functions in the sys schema. It was added in MySQL 5.7.9 to avoid issues if the DBA renames the root@localhost user. See also MySQL sys Schema […]
Understanding MySQL Privileges
The primary function of the MySQL authorization system is to associate an authenticated user with privileges on a database, such as SELECT, INSERT, UPDATE, and DELETE. The authorization system’s functionality includes the ability to have anonymous users and to enable specific functions such as LOAD DATA INFILE and various administrative operations. This authorization ensures that […]
Understanding MySQL Pluggable Authentication
MySQL supports a number of authentication mechanisms that are available through pluggable authentication. MySQL uses a number of algorithms to encrypt passwords stored in the user table: The mysql_native_password plugin implements the standard password format, a 41-byte-wide hash. The mysql_old_password plugin implements an older format that is less secure, being 16 bytes wide. The sha256_password […]
“imuxsock lost # messages from pid # due to rate-limiting” – rsyslog rate-limiting in Linux
Due to rate limiting by rsyslog, /var/log/messages is showing lots of dropped message entries: … Nov 7 14:23:14 thx1138 rsyslogd-2177: imuxsock lost 516 messages from pid 159386 due to rate-limiting Nov 7 14:23:15 thx1138 rsyslogd-2177: imuxsock begins to drop messages from pid 159386 due to rate-limiting Nov 7 14:23:20 thx1138 rsyslogd-2177: imuxsock lost 512 messages […]
Beginners Guide to MySQL User Management
Managing users in MySQL gives you the ability to control what users can and cannot do. Create user accounts with different privileges that are appropriate to their function. Avoid using the root account – Constrain compromised applications and protect against mistakes during routine maintenance. Ensure data integrity by proper assignment of individual user privileges. Permit […]
How to List and Set SELinux Context for MySQL Server
What is SELinux Context When SELinux is enforced in the system, it checks for rules on which process can access which files, directories, and ports. Every file, process, directory, and the port has a special security label known as an SELinux context, which is a name used to determine whether a process can access a […]