wip: docs: add standalone in container instruction

examples/standalone/quickstart-containers.yaml

@@ -0,0 +1,46 @@
+apiVersion: gateway.networking.k8s.io/v1
+kind: GatewayClass
+metadata:
+  name: eg
+spec:
+  controllerName: gateway.envoyproxy.io/gatewayclass-controller
+---
+apiVersion: gateway.networking.k8s.io/v1
+kind: Gateway
+metadata:
+  name: eg
+spec:
+  gatewayClassName: eg
+  listeners:
+    - name: http
+      protocol: HTTP
+      port: 8888
+---
+apiVersion: gateway.networking.k8s.io/v1
+kind: HTTPRoute
+metadata:
+  name: backend
+spec:
+  parentRefs:
+    - name: eg
+  hostnames:
+    - "www.example.com"
+  rules:
+    - backendRefs:
+        - group: "gateway.envoyproxy.io"
+          kind: Backend
+          name: backend
+      matches:
+        - path:
+            type: PathPrefix
+            value: /
+---
+apiVersion: gateway.envoyproxy.io/v1alpha1
+kind: Backend
+metadata:
+  name: backend
+spec:
+  endpoints:
+    - fqdn:
+        hostname: local-server.local
+        port: 3000

site/content/en/latest/tasks/operations/standalone-deployment-mode.md

@@ -16,7 +16,9 @@ Currently, Envoy Gateway only support the file provider and the host infrastruct
 - The file provider will configure the Envoy Gateway to get all gateway-api resources from file system.
 - The host infrastructure provider will configure the Envoy Gateway to deploy one Envoy Proxy as a host process.
 
-## Quick Start
+# Quick Start
+
+## Running locally on the host machine
 
 In this quick-start, we will run Envoy Gateway in standalone mode with the file provider
 and the host infrastructure provider.
@@ -40,7 +42,7 @@ The compiled binary lies in `bin/{os}/{arch}/envoy-gateway`.
 
 ### Create Certificates
 
-All runners in Envoy Gateway are using TLS connection, so create these TLS certificates locally to 
+All runners in Envoy Gateway are using TLS connection, so create these TLS certificates locally to
 ensure the Envoy Gateway works properly.
 
 ```shell
@@ -126,5 +128,131 @@ curl --verbose --header "Host: www.example.com" http://0.0.0.0:8888/
 * Connection #0 to host 0.0.0.0 left intact
 ```
 
+## Running in a Container
+
+In this quick-start, we will run Envoy Gateway in standalone mode with the file provider
+and the host infrastructure provider.
+
+### Prerequisites
+
+Create a local directory just for testing:
+
+```shell
+mkdir -p /tmp/envoy-gateway-test/config
+chmod -R 777 /tmp/envoy-gateway-test
+```
+
+Create a container network to run Envoy Gateway and a local server:
+
+```shell
+docker network create envoy-gateway-test
+```
+
+It's important to widen permissions of a created directory to avoid `Permission denied` error
+
+### Create Certificates
+
+All runners in Envoy Gateway are using TLS connection, so create these TLS certificates locally to
+ensure the Envoy Gateway works properly.
+
+```shell
+docker run --rm --volume /tmp/envoy-gateway-test:/tmp/envoy-gateway envoyproxy/gateway:{{< helm-version >}} certgen --local
+```
+
+### Start Envoy Gateway
+
+The following configuration should be placed into `/tmp/envoy-gateway-test/standalone.yaml` on the host:
+
+```yaml
+apiVersion: gateway.envoyproxy.io/v1alpha1
+kind: EnvoyGateway
+gateway:
+  controllerName: gateway.envoyproxy.io/gatewayclass-controller
+provider:
+  type: Custom
+  custom:
+    resource:
+      type: File
+      file:
+        paths: ["/tmp/envoy-gateway/config"]
+    infrastructure:
+      type: Host
+      host: {}
+logging:
+  level:
+    default: info
+extensionApis:
+  enableBackend: true
+```
+
+Start Envoy Gateway by the following command:
+
+```shell
+$ docker run \
+  --name envoy-gateway \
+  --network envoy-gateway-test \
+  --publish 8888:8888 \
+  --volume /tmp/envoy-gateway-test:/tmp/envoy-gateway \
+  --detach \
+  envoyproxy/gateway:{{< helm-version >}} \
+  server --config-path /tmp/envoy-gateway/standalone.yaml
+```
+
+As you can see, we have enabled the [Backend][] API, this API will be used to represent our local endpoints.
+
+### Trigger an Update
+
+Any changes under watched `paths` will be considered as an update by the file provider.
+
+For instance, copying example file into `/tmp/envoy-gateway/config` will trigger an update of gateway-api resources:
+
+```shell
+cp examples/standalone/quickstart-containers.yaml /tmp/envoy-gateway-test/config/
+```
+
+From the Envoy Gateway log, you should be able to observe that the Envoy Proxy has been started, and its admin address has been returned.
+
+### Test Connection
+
+Starts a simple local server in a same container network:
+
+```shell
+$ docker run \
+  --name local-server \
+  --hostname local-server.local \
+  --network envoy-gateway-test \
+  --detach \
+  python:3 \
+  python3 -m http.server 3000
+```
+
+The `--hostname` field values is used in `Backend` object of Envoy Gateway as FQDN.
+This way there is no need to update `Backend` object if IP address of container changed.
+
+Curl the example server through Envoy Proxy:
+
+```shell
+curl --verbose --header "Host: www.example.com" http://0.0.0.0:8888/
+```
+
+```console
+*   Trying 0.0.0.0:8888...
+* Connected to 0.0.0.0 (0.0.0.0) port 8888
+* using HTTP/1.x
+> GET / HTTP/1.1
+> Host: www.example.com
+> User-Agent: curl/8.11.1
+> Accept: */*
+>
+* Request completely sent off
+< HTTP/1.1 200 OK
+< server: SimpleHTTP/0.6 Python/3.13.1
+< date: Wed, 29 Jan 2025 17:04:11 GMT
+< content-type: text/html; charset=utf-8
+< content-length: 877
+<
+...
+* Connection #0 to host 0.0.0.0 left intact
+```
 
 [Backend]: ../../../api/extension_types#backend