To achieve high availability you can place multiple instances of APM Server behind a regular HTTP load balancer, for example HAProxy or nginx.
/healthcheck always returns a
You can configure your load balancer to send HTTP requests to this endpoint
to determine if an APM Server is running.
In case of temporal issues, like unavailable Elasticsearch or a sudden high workload, the data is buffered in an internal memory queue and ingestion retried.
If a given APM Server process fails, the data that has not yet been forwarded to Elasticsearch is lost.