Why you should use the system ready project

Error reporting and root cause analysis

When a system fails to become ready after a certain amount of time, the follow up question is : “What is wrong?”. So the framework also provides a way for each system check to report back information about errors.

One typical error is that a DS component does not come up because some mandatory dependency is not present. This dependency can be a configuration or maybe a service reference. In many cases, a trivial error like a missing configuration for a low level component can cause a lot of other components to fail to register. The root cause analysis allows traversing the trees of components and to narrow the reason for the system not being ready to a minimal number of possible causes for the failure state.

Use cases

Typical use cases for the system ready check ordered by the phase of the development cycle.

Development

• Coarse check of a pax exam based setup before letting the actual junit tests work on the system
• Determining the root cause of a pax exam based setup not starting

QA

• Starting system tests as soon as a system is ready for the tests to proceed
• Determining the root cause for an OSGi based system not starting up

Deployment

• Signaling when a system is ready after an upgrade so that it can receive traffic in the case of blue / green deployments

Production

• Periodic Ready health checks for system and signaling this state to monitoring systems
• Container automation and driving autopilot container deployments.

Added value when using the system ready framework

• Increased deployment resilience as deployments are checked before being exposed
• Faster deployments / upgrades by replacing fixed, error-prone waits with ready based waits
• Lower bug tracking efforts in tests as root causes are easier to find
• Configurability of when a certain deployment is considered ready (e.g. after content sync with an external service)