Health monitoring
Overview#
REST APIs will often be situated behind a load balancer that uses a monitor URL
for its configuration. Having a load balancer query the QuestDB REST endpoints
(on port 9000 by default) will cause internal logs to become excessively
noisy. Additionally, configuring per-URL logging would increase server latency.
To provide a dedicated health check feature that would have no performance knock
on other system components, we opted to decouple health checks from the REST
endpoints used for querying and ingesting data. For this purpose, a min HTTP
server runs embedded in a QuestDB instance and has a separate log and thread
pool configuration.
Usage#
The min server is enabled by default and will reply to any HTTP GET request
to port 9003:
The server will respond with a HTTP status code of 200, indicating that the
system is operational:
Path segments are ignored which means that optional paths may be used in the URL and the server will respond with identical results, e.g.:
Configuration#
The configuration section for the min HTTP server is available in the
minimal HTTP server reference.