Function Autoscaling

Function Autoscaler Operations

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The self-managed stack deploys the Function Autoscaler for the control and all observability profiles. State Metrics must remain enabled for both. See Observability Configuration for profile and metrics backend settings.

Verify the deployment

Check State Metrics and the Function Autoscaler:

kubectl get deployment -n nvcf \
  -l app.kubernetes.io/instance=state-metrics
kubectl get deployment -n nvcf \
  -l app.kubernetes.io/instance=function-autoscaler
kubectl rollout status deployment/function-autoscaler -n nvcf

Confirm the resolved PromQL endpoint. This ConfigMap does not contain the backend credentials:

kubectl get configmap -n nvcf function-autoscaler-env \
  -o jsonpath='{.data.TIMESERIES_DB__TIMESERIES_DB_URL}{"\n"}'

For the bundled backend, the result should point to vmsingle in the configured monitoring namespace. For an existing backend, it should match metricsBackend.promqlEndpoint.

Health endpoints

The Function Autoscaler exposes three health endpoints:

EndpointPurposeUse as
GET /admin/health/livenessAlways returns 200. Indicates the process is alive.Kubernetes liveness probe.
GET /admin/health/readinessReturns 200 when all components are healthy, 503 otherwise.Kubernetes readiness probe.
GET /healthReturns per-component health for cassandra_client and timeseries_db_client.Operator-facing detail and dashboards.

Inspect the detailed endpoint through the service:

kubectl port-forward -n nvcf service/function-autoscaler 8181:8181
curl http://127.0.0.1:8181/health

The liveness probe does not check Cassandra or the metrics backend. Dependency failures change readiness instead.

Troubleshooting

SymptomCheck
Function Autoscaler is not installedUse the control or all profile. Keep stateMetrics.enabled: true.
cassandra_client is unhealthyCheck contact-point DNS, credentials, and the configured TLS files.
timeseries_db_client is unhealthyCheck the resolved PromQL endpoint, authentication mode, credentials, and backend retention.
Scaling decisions are not appliedCheck NVCF API authentication and function status.
Discovery does not find active functionsConfirm the backend contains the request and State Metrics data listed in Architecture. Check the discovery lock metrics and TTL.

See also