New Install Reference Documentation

docs/content/reference/install-configuration/observability/healthcheck.md

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+---
+title: "Traefik Health Check Documentation"
+description: "In Traefik Proxy, CLI & Ping lets you check the health of your Traefik instances. Read the technical documentation for configuration examples and options."
+---
+
+# CLI & Ping
+
+Checking the Health of your Traefik Instances
+{: .subtitle }
+
+## CLI
+
+The CLI can be used to make a request to the `/ping` endpoint to check the health of Traefik. Its exit status is `0` if Traefik is healthy and `1` otherwise.
+
+This can be used with [HEALTHCHECK](https://docs.docker.com/engine/reference/builder/#healthcheck) instruction or any other health check orchestration mechanism.
+
+### Usage 
+
+```sh
+traefik healthcheck [command] [flags] [arguments]
+```
+
+Example:
+
+```sh
+$ traefik healthcheck
+OK: http://:8082/ping
+```
+
+## Ping
+
+The `/ping` health-check URL is enabled with the command-line `--ping` or config file option `[ping]`.
+
+The entryPoint where the `/ping` is active can be customized with the `entryPoint` option,
+whose default value is `traefik` (port `8080`).
+
+| Path    | Method        | Description                                                                                         |
+|---------|---------------|-----------------------------------------------------------------------------------------------------|
+| `/ping` | `GET`, `HEAD` | An endpoint to check for Traefik process liveness. Return a code `200` with the content: `OK` |
+
+### Configuration Example
+
+To enable the API handler:
+
+```yaml tab="File (YAML)"
+ping: {}
+```
+
+```toml tab="File (TOML)"
+[ping]
+```
+
+```bash tab="CLI"
+--ping=true
+```
+
+### Configuration Options
+
+| Field | Description                                               | Default              | Required |
+|:------|:----------------------------------------------------------|:---------------------|:---------|
+| `ping.entryPoint` | Enables `/ping` on a dedicated EntryPoint. | traefik  | No   |
+| `ping.manualRouting` | Disables the default internal router in order to allow one to create a custom router for the `ping@internal` service when set to `true`. | false | No   |
+| `ping.terminatingStatusCode` | Defines the status code for the ping handler during a graceful shut down. See more information [here](#terminatingstatuscode) | 503 | No   |
+
+#### `terminatingStatusCode`
+
+During the period in which Traefik is gracefully shutting down, the ping handler
+returns a `503` status code by default.  
+If Traefik is behind, for example a load-balancer
+doing health checks (such as the Kubernetes LivenessProbe), another code might
+be expected as the signal for graceful termination.  
+In that case, the terminatingStatusCode can be used to set the code returned by the ping
+handler during termination.
+
+```yaml tab="File (YAML)"
+ping:
+  terminatingStatusCode: 204
+```
+
+```toml tab="File (TOML)"
+[ping]
+  terminatingStatusCode = 204
+```
+
+```bash tab="CLI"
+--ping.terminatingStatusCode=204
+```