Python project for replication failover in a MySQL replication set.

Classification (U)

Description:

Used to conduct replication failover in a MySQL replica set, to include switching the best slave to master and selecting a specific slave to become master.

This README file is broken down into the following sections:

• Features
• Prerequisites
• Installation
• Configuration
• Program Help Function
• Testing
  • Unit

Features:

• Automatically switching the master to the best slave.
• Selecting a specific slave to become the new master.
• Displaying the best slave in the replica set.
• Show all the slaves in the replica set from best to worst.

Prerequisites:

• List of Linux packages that need to be installed on the server.

  • git
  • python-pip

• Local class/library dependencies within the program structure.

  • python-lib
  • mysql-lib

Installation:

Install this project using git.

• From here on out, any reference to {Python_Project} or PYTHON_PROJECT replace with the baseline path of the python program.

umask 022
cd {Python_Project}
git clone git@github.com:deepcoder42/mysql-failover.git

Install/upgrade system modules.

cd mysql-failover
sudo bash
umask 022
pip install -r requirements.txt --upgrade --system
exit

Install supporting classes and libraries.

pip install -r requirements-python-lib.txt --target lib --system
pip install -r requirements-mysql-lib.txt --target mysql_lib --system
pip install -r requirements-python-lib.txt --target mysql_lib/lib --system

Configuration:

Create a MySQL slave configuration file. Make the appropriate change to the environment.

• Change these entries in the MySQL slave setup:

  • user = USER
  • japd = PSWORD
  • rep_user = REP_USER
  • rep_japd = REP_PSWORD
  • host = HOST_IP
  • name = HOST_NAME
  • sid = SERVER_ID
  • port = 3306
  • extra_def_file = 'DIRECTORY_PATH/mysql.cfg'

• Change these entries only if required:

  • cfg_file = None
  • serv_os = "Linux"
  • port = 3306

• If SSL connections are being used, configure one or more of these entries:

  • ssl_client_ca = None
  • ssl_client_key = None
  • ssl_client_cert = None

• Only changes these if necessary and have knowledge in MySQL SSL configuration setup:

  • ssl_client_flag = None
  • ssl_disabled = False
  • ssl_verify_id = False
  • ssl_verify_cert = False

• Create a new set of entries for each slave in the MySQL replica set.

cp slave.txt.TEMPLATE slave.txt
vim slave.txt
chmod 600 slave.txt

Create MySQL definition file. Make the appropriate change to the MySQL definition setup.

• Change these entries in the MySQL configuration file:
• Note: socket use is only required to be set in certain conditions when connecting using localhost.
  • password="PASSWORD"
  • socket=DIRECTORY_PATH/mysqld.sock

cp mysql.cfg.TEMPLATE mysql.cfg
vim mysql.cfg
chmod 600 mysql.cfg

Program Help Function:

The program has a -h (Help option) that will show display an usage message. The help message will usually consist of a description, usage, arugments to the program, example, notes about the program, and any known bugs not yet fixed. To run the help command:

{Python_Project}/mysql-failover/mysql_rep_failover.py -h

Testing:

Unit Testing:

Installation:

Install the project using the procedures in the Installation section.

Unit test runs for mysql_rep_failover.py:

Testing:

cd {Python_Project}/mysql-failover
test/unit/mysql_rep_failover/unit_test_run.sh

Code coverage:

cd {Python_Project}/mysql-failover
test/unit/mysql_rep_failover/code_coverage.sh