> ## Documentation Index
> Fetch the complete documentation index at: https://notes.kodekloud.com/llms.txt
> Use this file to discover all available pages before exploring further.
# Extensions healthcheck
> Describes the OpenTelemetry Collector health_check extension that provides an HTTP health endpoint for monitoring, load balancer probes, and Kubernetes liveness and readiness checks
The health check extension provides a lightweight HTTP endpoint that confirms whether the OpenTelemetry Collector process is up and responding. When enabled, the endpoint returns a 200 OK and a small JSON payload with status, `upSince`, and `uptime` — making it ideal for monitoring, load balancer probes, and orchestration systems.
## Enable the health\_check extension
Add the `health_check` extension to your collector configuration and bind it to the default address and port (0.0.0.0:13133):
```yaml theme={null}
extensions:
health_check:
endpoint: "0.0.0.0:13133" # GET / returns 200 OK when healthy
service:
extensions: [health_check] # ensure it is enabled under service
```
## Verify the endpoint with curl
A GET request to `/` returns HTTP 200 and a JSON body describing server availability:
```bash theme={null}
curl -i http://localhost:13133/
HTTP/1.1 200 OK
Content-Type: application/json
Content-Length: 118
{
"status": "Server available",
"upSince": "2025-09-18T12:41:48.996342661Z",
"uptime": "2m41.853715676s"
}
```
The extension listens by default on port 13133. You can use this endpoint in health checks, load balancer probes, or external orchestration tools to decide rollout and restart behavior.
## Kubernetes: map to liveness and readiness probes
Use the health endpoint for Kubernetes liveness and readiness checks so the platform can detect and recover from unhealthy collector instances:
```yaml theme={null}
livenessProbe:
httpGet:
path: "/"
port: 13133
initialDelaySeconds: 10
periodSeconds: 10
readinessProbe:
httpGet:
path: "/"
port: 13133
initialDelaySeconds: 5
periodSeconds: 5
```
Probes summary:
| Probe type | Purpose | Example |
| ---------- | ----------------------------------------------------------------- | --------------------------- |
| Liveness | Restart container when collector is unresponsive | `livenessProbe` YAML above |
| Readiness | Exclude pod from service load balancer while starting/rehydrating | `readinessProbe` YAML above |
## Docker / Docker Compose
For Docker or Docker Compose deployments, expose the collector port so external systems (host, orchestrator, CI) can poll the endpoint:
```yaml theme={null}
services:
otelcol:
image: otel/opentelemetry-collector:latest
ports:
- "13133:13133"
```
External systems can poll `http://:13133/` for a quick health signal and use the 200 OK response for rollout, restart, or monitoring decisions.
## When to use the healthcheck extension
* Integrate with Kubernetes probes (liveness & readiness).
* Configure load balancer health checks to avoid routing traffic to an unavailable collector.
* Use in CI/CD pipelines or deployment scripts to gate rollouts on collector availability.
* Provide a simple browser-accessible endpoint for quick diagnostic checks.
## Links and references
* [OpenTelemetry Collector — Extensions](https://opentelemetry.io/docs/collector/architecture/#extensions)
* [Kubernetes Probes — Liveness and Readiness](https://kubernetes.io/docs/tasks/configure-pod-container/configure-liveness-readiness-startup-probes/)
* [Docker Compose — Expose ports](https://docs.docker.com/compose/compose-file/compose-file-v3/#ports)