Misc (Cloud Migration)

Unobvious on-premise costs

• Labor
  • broken disks
  • patching hosts
  • servers going offline
• Network 
  • Bandwidth needs (peak/average)
• Capacity/Utilization
  • Cost of overprovisioning
  • How much buffer capacity
    • what to do when exceeded
• Availability
  • Do you have DR
• Power
  • What is peak/average power requirements
  • HVAC
  • 2N redundancy (everything is duplicated)
• Space
  • How much can you grow

Migration Bubble

• Temporarily increased costs
  • Planning and assessment
  • Duplicate environments
  • Staff Training
  • Migration Consulting
  • 3rd Party Tooling
  • Lease penalties
    • Due to early termination of contracts

Methodology

• Evaluate
  • Migration Readiness Assessment (MRE)
    • Are we ready?
    • Do we have all resources?
• Plan
  • MRE and Planning Engagement
• Design
• Migrate
  • Execution
    • Discovery
      • What do I have
    • Grouping / Mapping
      • Servers into application stacks
      • Always migrate verticals
        • Horizontal move (e.g. DB first) unrealistic
    • Migration Strategy
      • See below (6R Approach )
    • Data Migration
    • Landing Zone
    • Server Migrations
    • Database Migrations
• Optimize

Migration Strategy (6R Approach)

• Retain (Revisit)
  • Do not touch
    • e.g. mainframe that must stay
• Remove
  • Decomission
• Rehost
  • aka Lift&Shift
  • Minimal changes to application
    • typically configuration only
  • Storage migration needed
  • e.g. 
    • Import VM as-is 
• Replatform
  • Up-version of OS
  • Data Conversion
    • e.g. MysQL  -> RDS (PostgreSQL)
• Refactor
  • Change to use Cloud native mechanisms, e.g.
    • multi-region
    • Auto-Scaling
• Rearchitecture
  • Complete rewrite
    • e.g. Server -> Serverless

Difficulties in migration

• Coordination
• Lack of testing
• Server downtime during cutover

References

• https://www.youtube.com/watch?v=ij43Vn-2qcU
• https://www.youtube.com/watch?v=kxtcB21xXzM