# Healthcheck & monitoring

## Healthcheck

Use Datalore's in-built HTTP endpoint (accessible at `/health`) to verify whether the instance has become online and responsive.

This endpoint and returns `OK` when no issues are detected.

Use the same endpoint as [Kubernetes liveness probe](https://github.com/JetBrains/datalore-configs/blob/2026.3/charts/datalore/templates/statefulset.yaml) if default Helm charts are used for the deployment.

## Monitoring

Datalore has a built-in metrics exporter, which is disabled by default and accessible at the `/metrics` path when enabled explicitly.

There are two mutually exclusive environment variables of the Datalore server that can be used to enable metrics:

### Monitoring environment variables

`METRICS_AUTH_TOKEN`
: String
:
:
:
: Enables the exporter and defines the authentication token required to collect metrics.
:
:
:
: Mutually exclusive with `ENABLE_UNAUTHORIZED_METRICS.`
:
:
:
: Default: not defined

`ENABLE_UNAUTHORIZED_METRICS`
: String
:
:
:
: Enables the exporter. No authentication will be required to read metrics.
:
:
:
: Mutually exclusive with `METRICS_AUTH_TOKEN.`
:
:
:
: Default: not defined

> **Note:**
> If both of the variables are defined, the authentication will still be enforced.

## Metrics

> **Tip:**
> While Datalore exposes significantly more metrics than listed below, only those included in this list have guaranteed backwards compatibility.

1.

`agent_pool_size`: shows how many agents the pool currently has.

* Prometheus query: `sum by (instance_name)(agent_pool_size)`

2.

`agent_waiting_time_bucket`: represents the timespan in which the user waited for an instance startup.

* Prometheus query: `sum(increase(agent_waiting_time_bucket[10m])) by (le)`

3.

`agent_in_pool_time_bucket`: represents the timespan in which the agent was online and idle before being assigned to a specific notebook.

* Prometheus query: `sum(increase(agent_in_pool_time_bucket[10m])) by (le)`

4.

`agents_started_total`: shows how many agents were started per minute.

* Prometheus query: `sum by (instance_name)(rate(agents_started_total[5m])) * 60`