Cloud Migration: Moving from On-Premise to Cloud
Cloud migration is the process of moving applications, data, and infrastructure from on-premise data centres to cloud platforms. It is rarely a simple "lift and shift" — the most value comes from redesigning systems to take advantage of cloud-native capabilities. A structured approach minimises risk and disruption.
The 6 Rs of Cloud Migration
- Rehost (lift and shift): Move as-is to cloud VMs. Fastest, lowest risk. Limited cloud benefit — no architecture changes.
- Replatform (lift, tinker, and shift): Make targeted optimisations without fundamental redesign — e.g. migrate to a managed database service while keeping the application unchanged
- Refactor / Re-architect: Redesign the application to be cloud-native — containers, serverless, managed services. Most benefit, most work.
- Repurchase: Replace on-premise software with cloud-native SaaS equivalent
- Retire: Decommission systems that are no longer needed
- Retain: Keep on-premise — some systems are better kept where they are
Migration Approach
- Assess: Inventory applications, map dependencies, assess cloud readiness
- Plan: Define migration waves, prioritise by value and complexity, define rollback procedures
- Migrate: Execute migrations in waves, starting with lowest-risk workloads
- Optimise: Right-size, optimise costs, implement cloud-native features
Common Migration Risks
- Underestimating network latency between migrated and retained on-premise systems
- Licensing issues — some software licences do not permit cloud deployment
- Data migration complexity and downtime requirements
- Team skills gap — cloud operations require different skills than on-premise