Database Migration using AWS Database Migration Service

• In the previous session we have create a vm and installed the mysql db
• We have the following users in mysql database

select user from mysql.user;

* To do the the migration we need some database to be present with tables and records in mysql
* Lets configure the employees database Refer Here
* Steps:

git clone https://github.com/datacharmer/test_db.git
cd test_db
sudo mysql -t < employees.sql

* Now lets use the following commands

create user 'migration'@'%' Identified by 'MotherIndia@123';
GRANT ALL PRIVILEGES ON employees.* TO 'migration'@'%';

• Now lets test the connectivity from other machine
• To fix the connectivity change the bind address from 127.0.0.1 to 0.0.0.0 /etc/mysql/mysql.conf.d/mysqld.cnf
  
• Restart the mysql service

sudo systemctl daemon-reload
sudo service mysql restart

• Now test the connection from mysql command line or mysql workbench
  
• Refer Here for installing mysql shell on windows
• Refer Here to download workbench

Migration Approaches

• Our aim is to migrate the database from on-premises to AWS RDS
  
• Data in the database will be constantly updated by applications, so database is constantly changing.
• One approach for migration is to take the downtime (Offline Approach)
• Export the data from database into some format
• Create an RDS Instance and import the exported data
• Not possible if the database size is huge
• Second approach is online migration:
• Here we migrate the data using DMS to RDS in incremental fashion
• Then we will validate the data and run some comparision tests
• when everything is fine, we announce a cut over date and migrate