+++ title = "Configure Static Routes" description = "Serve static responses for health checks, maintenance pages, and other paths that should not trigger autoscaling" +++ Some requests such as external health probes should never trigger autoscaling. When the backend is scaled to zero, these requests still need a sensible response. Static routes let you define paths on an InterceptorRoute that serve a configurable static response without waking up the backend. ## Health check passthrough A common use case is a load balancer that probes `/healthz`. When the app is running, the probe should reach the real backend. When the app is scaled to zero, the interceptor returns a static `200 OK` instead of triggering a scale-up. ```yaml apiVersion: http.keda.sh/v1beta1 kind: InterceptorRoute metadata: name: my-app spec: target: service: my-app-svc port: 8080 scalingMetric: requestRate: targetValue: 100 staticRoutes: - rules: - paths: - value: /healthz response: statusCode: 200 body: "OK" ``` With the default `responseMode: WhenUnavailable`, the interceptor forwards `/healthz` to the backend when it has ready endpoints. When the backend is down, the static response is returned. ## Maintenance page Serve a maintenance page when the backend is unavailable, without triggering a scale-up. With `responseMode: Always`, the static response is returned even when the backend is running which is useful e.g. for a planned downtime. For larger response bodies, store the content in a ConfigMap instead of inline. The ConfigMap must have the label `http.keda.sh/response-body: "true"`. ```yaml apiVersion: v1 kind: ConfigMap metadata: name: maintenance-page labels: http.keda.sh/response-body: "true" data: index.html: |

Under maintenance

--- apiVersion: http.keda.sh/v1beta1 kind: InterceptorRoute metadata: name: my-app spec: target: service: my-app-svc port: 8080 scalingMetric: requestRate: targetValue: 100 staticRoutes: - rules: - paths: - value: / responseMode: Always response: bodyFromConfigMap: name: maintenance-page key: index.html headers: Content-Type: text/html statusCode: 503 ``` When `key` is omitted, it is derived from the request path (without the leading `/`, defaulting to `index.html` for `/`). The `Content-Type` header is auto-detected from the key's file extension unless explicitly set in `headers`. ## Multiple static routes You can define multiple static routes on a single InterceptorRoute. They are evaluated in list order; the first matching route wins. ```yaml staticRoutes: - rules: - paths: - value: /healthz response: statusCode: 200 body: "OK" - rules: - paths: - value: /old-api responseMode: Always response: statusCode: 307 headers: Location: /api ``` ## Response modes The `responseMode` field controls when the static response is served: | Mode | Behavior | | ----------------- | ------------------------------------------------------------------------------------------------------------- | | `WhenUnavailable` | Forward to the backend when it has ready endpoints; return the static response only when the backend is down. | | `Always` | Always return the static response, even when the backend is running. | The default is `WhenUnavailable`, which suits health checks that should reach the real backend when it is available. Use `Always` for redirects or paths that should never reach the backend. ## Matching rules Static routes use the same matching rules as the top-level `rules` field on an InterceptorRoute: hosts, path prefixes, and headers. Multiple rules within a single static route use OR semantics — a request matching any rule is handled by that static route. For details on host, path, and header matching, see [Configure Routing Rules](../configure-routing/). ## Static routes vs. cold-start placeholders Static routes and [cold-start placeholders](../configure-cold-start/) both serve static responses, but for different purposes: - **Cold-start placeholders** respond to requests that _should_ trigger scaling. The placeholder is a temporary response while the backend starts up. - **Static routes** respond to requests that should _never_ trigger scaling. Depending on `responseMode`, the static response is served when the backend is unavailable or unconditionally. ## What's Next - [InterceptorRoute Reference](../reference/interceptorroute/) — field details for `staticRoutes`. - [How Routing Works](../concepts/routing/) — request matching and priority order. - [How Scaling Works](../concepts/scaling/) — metrics, scale-to-zero, and cold starts.