The situation
What needs investigation
An application is moving from on-premises infrastructure or another cloud. The migration plan must account for application dependencies, database state, network paths, DNS, external integrations, and the period where old and new environments coexist.
Signals we look for
Application
- service dependencies
- configuration and secrets
- background jobs and schedules
Data
- database size and change rate
- replication or export method
- validation and recovery path
Network
- private connectivity
- DNS and certificate changes
- inbound and outbound rules
Cutover
- traffic switching
- rollback criteria
- post-cutover validation
How we investigate
Each step is validated against the workload before the next change.
- 01
Inventory dependencies
Map application, data, identity, network, and third-party dependencies.
- 02
Choose migration waves
Sequence low-risk and tightly coupled workloads deliberately.
- 03
Build the target
Create AWS networking, compute, data, access, and monitoring foundations.
- 04
Rehearse data movement
Validate replication, export, restore, and data checks before cutover.
- 05
Plan DNS and traffic
Define TTL, load-balancer, certificate, and reversal actions.
- 06
Validate after cutover
Check user flows, jobs, metrics, logs, and error paths.
Architecture / decision path
Example engineering decision
Illustrative cutover decision — not customer data
Database change ratecontinuous writes
DNS TTLreduced before cutover
Rollback conditioncritical user flow fails
Engineering interpretation
DNS changes alone do not make a cutover safe. The migration needs a data-consistency plan and a reversible traffic decision that considers the period after new writes begin.
Possible next investigation
- Define write freeze or replication strategy.
- Test restore and reconciliation steps.
- Validate public and private DNS paths.
- Run a cutover rehearsal with the rollback decision owner.
Trade-offs we consider
Downtime
Shorter downtime may require replication and more migration complexity.
Data consistency
A fast cutover is unsafe if write handling is not defined.
Sequence
Moving dependent systems together can reduce integration risk but increase blast radius.
Rollback
The old path stays useful only while data and configuration remain compatible.
What the engagement can produce
Typical outputs for this type of work
Scope depends on the environment and the problem being investigated.
- dependency inventory
- target AWS architecture
- migration wave plan
- cutover and rollback runbook
- validation checklist
- post-migration monitoring plan