---
title: "Native bootstrap"
url: "/reference/configuration/native-bootstrap/"
kind: "reference"
summary: "The bootstrap: key — Arion's native resource form, its top-level keys, and how it relates to envoy_bootstrap."
---

> Arion site index: [/llms.txt](/llms.txt)

# Native bootstrap

The bootstrap: key — Arion's native resource form, its top-level keys, and how it relates to envoy_bootstrap.

The `bootstrap:` key of the [configuration file](@/reference/configuration/file-format.md) accepts the same resources as `envoy_bootstrap:`, but in Arion's own serialization — the shape of its internal configuration model, without the Envoy field names and conversions.

`envoy_bootstrap` is the canonical dialect used throughout this documentation; this page is the only one that documents the native form. A file may set one of the two keys, never both. Everything Envoy-shaped that Arion accepts is listed in the [supported-configuration matrix](@/reference/envoy-compatibility/supported-configuration.md); the native form can express exactly the same set, no more.

## Top-level keys

| Field | Type | Required | Default | Description |
|---|---|---|---|---|
| `static_resources` | object | no | empty | `listeners`, `clusters` and `secrets`, in native shapes. |
| `dynamic_resources` | object | no | unset | `grpc_cluster_specifiers`: a list of cluster names to reach the xDS control plane, replacing Envoy's `ads_config.grpc_services`. |
| `node` | object | no | unset | xDS node identity: `id` and `cluster_id` (Envoy's `node.cluster`). |
| `admin` | object | no | unset | Admin interface; `address` is the listening socket. |
| `stats_flush_interval` | object | no | unset | Flush interval for stats sinks, as `secs` and `nanos` fields (not a duration string). |
| `stats_sinks` | list | no | `[]` | Stats sinks; the OpenTelemetry sink with `grpc_service` and `prefix`. |

## Example

```yaml,name=arion.yaml,arion=fragment
bootstrap:
  node:
    id: arion-1
    cluster_id: edge
  dynamic_resources:
    grpc_cluster_specifiers: [xds]
  static_resources:
    clusters:
      - name: xds
        static:
          cluster_name: xds
          endpoints:
            - Socket:
                - 127.0.0.1
                - 50051
        connect_timeout: 250ms
```

## How the native form differs

- **Field names follow the internal model.** For example `node.cluster_id` instead of `node.cluster`, `dynamic_resources.grpc_cluster_specifiers` instead of the nested `ads_config.grpc_services` block, and a cluster's discovery type appears as a key (`static:`, `strict_dns:`, `EDS:`, `ORIGINAL_DST:`) holding its settings instead of `type:` plus `load_assignment:`.
- **Enums are single-key maps inside `static_resources`** (as in the `Socket:` address above) and YAML tags elsewhere.
- **Endpoint lists are simplified**: a single priority-0 group of healthy, weight-1 endpoints is written as a plain list of addresses; the full `priority` / `lb_endpoints` form is also accepted.
- **Parsing is plain serde**, not the strict protobuf mapping used inside `envoy_bootstrap`, so only the exact native field names are accepted — there are no camelCase aliases.

The authoritative rendering of any configuration in the native form is the admin interface: `GET /config_dump` returns the running configuration in exactly this serialization, as JSON. Load a config via `envoy_bootstrap` and read `/config_dump` to see its native equivalent — see the [admin API](@/reference/observability/admin-api.md).

> [!NOTE]
> Prefer `envoy_bootstrap` unless you have a tool that produces the native form. The Envoy dialect is what the examples, guides and reference pages on this site use, and it round-trips through the same internal model.