Episode 351 - Bernd Rücker on Orchestrating Microservices with Workflow Management

System Components

Workflow management systems are essential for orchestrating microservices, acting as state machines that track and manage the flow of processes. Bernd Rücker explains that these systems create instances of workflows based on predefined blueprints, ensuring processes follow a specific order and can persist state when necessary 1. This capability is crucial in distributed systems where network issues or asynchronous communication can cause delays. Rücker highlights the use of BPMN, a domain-specific language, which facilitates clear modeling and understanding of workflows even for non-technical stakeholders 2.

The workflow engine is a state machine, so it can persist state for however long you want to.

--- Bernd Rücker

This persistence allows for handling complex scenarios like retries and compensations, enhancing the reliability and visibility of microservices 3.

   

State Management

Ensuring transactional integrity in microservices is challenging, especially when dealing with external systems. Rücker emphasizes the importance of idempotency, where services can handle duplicate requests without adverse effects, as a key strategy in maintaining consistency 4. The saga pattern is another critical concept, allowing for compensating actions when a process step fails, such as canceling a hotel booking if a flight cannot be secured 5.

You have to remember what you already called and then you have to undo that correctly.

--- Bernd Rücker

This approach, supported by workflow engines, ensures that stateful processes can be managed effectively, even in complex distributed environments 3.