Scenario: Migration

• Lets assume that organization LT Corp Wants to start using AWS.
• They have existing infrastructure which they use to run the applications
  
• The basic idea of LT Corp is to move all of the applications to the AWS.
  

Execution Plan From 10,000 Feet

• In AWS, we have a Service called as
• Server Migration Service (SMS) using which we migrate Virtual Machines from on-premises to AWS EC2 instances
• Database Migration Service (DMS) using which we can migrate Databses into AWS RDS instances
• AWS SMS:
• AWS can migrate Virtual Machines from
  • VMWare vSphere
  • Microsoft Hyper-V/SCVMM
  • Microsoft Azure
• For doing this migration there are requirements & supported OS
• AWS DMS:
• AWS Supports the following Databases to migrate
  • Oracle
  • Microsoft SQL Server
  • Postgres
  • MySQL
  • MongoDB
• Todo’s for unsupported Databases
• Migrate the Virtual Machine and try to run your database as an ec2 instance
• Todo’s for unsupported OS:
• Generally older versions of linux OS are unsupported, so upgrade the existing virtual machines to the supported OS Version
• When we do the migration, we have 3 major activities as admins
• Pre-Migration Tasks
• Migration
• Post-Migration Tasks

6 Strategies for Migrating Applications to the Cloud (6 R’s)

• The Strategies are
• Rehosting (Lift and Shift):
  • We would like to move the application to cloud and would expect it to run on same/similar configuration like on-premises.
  • We don’t want to have any changes in our application.
  • This can be done manually or in automated way using SMS
  • This is pure admin/Sys-ops job
• Replatforming (Lift-tinker-and-shift)
  • In order to acheive some tangible benifits, your existing application might be required to change a little bit (not changing the architecture)
  • Application is using WebLogic Service (Expensive Licensing), In AWS we can run tomcat an open source equivalent
  • In the above scenario, we have made a minor change and it saves us lot of cost
• Repurchasing
  • Rather than migrating this application, if we can purchase some existing system (Workday, Salesforce etc)
• Refactoring/Re-architecting:
  • Rearchitecting your application probably moving from monolith => Microservices etc
• Retire: Get rid of this application
• Retain: Revisi this migration later and do nothing for now
• Strategies Overview