Spring Boot actuator exposes health and metrics from the application to interested parties. This can be over JMX, HTTP, or exported to an external system.
The health endpoints tell something about the health of the application and/or the system it is running on. It will detect if the database is up, report the diskspace, etc. The metrics endpoints expose usage and performance statistics like number of request, the longest request, the fastest, the utilization of your connection pool, etc.
Problem
How to enable health and metrics in the application so that the status of the application can be monitored.
Solution
Add a dependency for the spring-boot-starter-actuator to and the health and metrics will be enabled and exposed for the application. Additional configuration can be done through properties in the management namespace.
The management.server properties are only effective when using an embedded server; when deploying to an external server these properties don’t apply anymore.
Problem
It is needed to expose certain metrics and have a health check that aren’t available by default in the application.
Solution
The health checks and metrics are pluggable, and beans of type HealthIndicator and MetricBinder are automatically registered to provide additional health checks and/or metrics. The task is to create a class implementing the desired interface and register an instance of that class as a bean in the context of having it contribute to the health and metrics.
Problem
How to export the metrics to an external system, to create a dashboard to monitor the application.
Solution
Use one of the supported systems like Graphite and periodically push the metrics to that system. Include a micrometer.io registry dependency in the application (next to the spring-boot-starter-actuator dependency) and metrics will automatically be exported. By default, every minute the data will be pushed to the server.