Case study
American National: phased IBM MQ to RabbitMQ migration.
Legacy messaging replaced in phases while the code that depended on it was refactored. No big-bang cutover.
The short answer
American National, an insurer, moved from IBM MQ to RabbitMQ in phases while the AceMQ engineering team refactored legacy code that depended on the old broker. The project was delivered by the AceMQ engineering team and shows the phased, reversible approach Ace8 applies to every modernization.
Customers
Partners
The situation
A legacy messaging layer with code attached
American National is an insurer. Its applications exchanged messages through IBM MQ, a proprietary message broker. As in most long-lived estates, application code had grown around the broker: connection handling, message formats and error paths written for one specific platform.
That coupling is what makes a broker change a code change. Swapping the broker without touching the code is rarely possible.
The goal
Replace the broker, keep the business running
The goal was to move from IBM MQ to RabbitMQ, an open-source broker, while the applications that depended on messaging kept running. The migration had to be phased, so no single cutover carried the whole estate.
The approach
Phases, not a switch
The steps below describe the shape of the approach. Phase-level detail will be added as the customer approves it.
- 1
Map the dependencies
Find which applications send and receive on which queues, and what each one assumes about delivery.
- 2
Refactor the legacy code
Change the code that was written around IBM MQ so that it can talk to a different broker.
- 3
Move in phases
Migrate queues and the applications attached to them in steps, with each step reviewed before the next.
- 4
Keep each step reversible
Each phase is reviewed before the next, consistent with the Ace8 principle that every step is reversible.
Legacy code refactoring
Why the code work mattered
A phased broker migration is mostly a code migration. Each application had to stop depending on IBM MQ specifics. Refactoring first, in small changes, meant each change could be checked and reversed on its own.
It is the same sequence Ace8 follows on app-server and Java upgrade projects: pin down behavior, change code in slices, move one capability at a time. See the 8 principles.
A further simplification
Kafka replaced by Debezium and RabbitMQ
In the same work, change data capture that had been handled with Kafka was replaced by Debezium together with RabbitMQ. That removed a component from the architecture. This detail is public and was approved by the customer.
Results
What we can state
American National approved naming the customer and describing the work. The scope figures (number of applications, queues, phases and cutover window) are being released with the customer's approval and will appear here exactly as approved. We do not publish figures that the customer has not cleared.
Today
What AceMQ runs today
AceMQ supports RabbitMQ around the clock. The same team that did the migration stays accountable for the new platform. Read more on supported after migration.
Lessons
Lessons that shape the Ace8 method
- Treat a platform swap as a code migration, because the code carries the dependency.
- Phase the work so that each step is small and reversible.
- Remove components, not just replace them, when the architecture allows.
- Plan the run before the cutover, so ownership does not change at go-live.
After go-live
Keep it running after cutover.
The AceMQ engineering team. Ace8 is the modernization practice of AceMQ, and this work shows the phased approach Ace8 applies.
The messaging layer, from IBM MQ to RabbitMQ, together with refactoring of the legacy code that depended on IBM MQ.
No. The migration was phased.
We scope it in the assessment. The broker can be a separate phase beside an application server exit.
Debezium together with RabbitMQ.
Know the cost before anything moves.
A fixed-price assessment gives you the inventory, the risk score and a phased plan. Scope and cost are fixed before the migration starts.
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