The Migration Playbook: Sequencing the Whole Thing
Every preceding section in this part has covered one piece of the migration in isolation – inventory, schema translation, code conversion, reconciliation, parallel run, governance, FinOps. None of that survives contact with a real program unless it’s sequenced into a single plan that says what happens in what order, what can run in parallel, what blocks what, who signs off at each gate, and exactly how far the team can walk back if something goes wrong. This section is where those pieces become one runbook.
That runbook is also the artifact a steering committee actually reads. A dependency graph and a risk register turn “we’re migrating to Databricks” into a schedule with named owners, quantified risks, and a rollback window everyone has agreed to in advance – the difference between a migration that has a plan and one that’s improvising in front of the business.
flowchart LR
A["Schema Freeze\n(hard block)"] --> B["Logic Conversion\n(hard block, sequential)"]
B --> C1["Table A: Ingest + Reconcile"]
B --> C2["Table B: Ingest + Reconcile"]
B --> C3["Table N: Ingest + Reconcile"]
C1 --> D["Parallel Run"]
C2 --> D
C3 --> D
D --> E["Cutover Decision\n(Steering Committee)"]
E --> F["72-Hour Rollback Window"]
F --> G["Decommission Legacy"]
R["Risk Register"] -.tracks.-> A
R -.tracks.-> B
R -.tracks.-> D
R -.tracks.-> E
Lectures
| # | Lecture | Est. Read |
|---|---|---|
| 1 | The End-to-End Migration Runbook | 3 min read |
| 2 | Sequencing: What Order, What Parallel, What Blocks What | 3 min read |
| 3 | The Risk Register: Naming Every Way It Can Fail | 3 min read |
| 4 | Stakeholder Communication and the Steering Committee | 3 min read |
| 5 | The 72-Hour Rollback Window | 3 min read |
| 6 | Check Your Knowledge | Quiz |
| ← Previous: Check Your Knowledge | Next: The End-to-End Migration Runbook → | |:—|—:|