Circuit breaker is a design pattern that is used to detect failures and encapsulates the logic of preventing a failure from constantly recurring. The circuit breaker design pattern works much like an electrical circuit breaker which is intended to “trip” or open the circuit when failure is detected. In a software application, a circuit breaker functions as a proxy that executes the remote services and monitors the remote service for failures. A failure can be an exception and/or a timeout. When the number of failures exceeds a predetermined threshold within a specified time period, the circuit breaker shuts off access to a service.

It is useful to develop a contingency plan, which describes what will be happening when the faulty service will be unreachable. You may either increase the retry period, re-route users to some other service or reduce functionality for the period of unavailability. This can prevent an application from repeatedly trying to execute an operation that's likely to fail, allowing it to continue without waiting for the fault to be fixed. The circuit breaker pattern also enables an application to detect whether the fault has been resolved. If the problem appears to have been fixed, the application can try to invoke the operation again.

Roxy-WI provides a great possibility to start Circuit Breaking in a couple of clicks.

Go to the Haproxy-Add proxy section. Choose what you would like to create: Listner or Backend. Press the Show Advanced settings button.

Tick the Circuit Breaking checkbox and choose parameters according to this description.