initial commit/draft of the API gateway docs

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---
layout: docs
page_title: API Gateway
description: Using Consul API gateway functionality
---
# Consul API Gateway
This topic describes how to use the Consul API Gateway module, which enables applications and services running in a datacenter to be accessed by network clients outside the datacenter. This type of network traffic is commonly referred to as "north-south" network traffic.
## Introduction
Consul API Gateway is an implementation of the Kubernetes Gateway API Specification (https://gateway-api.sigs.k8s.io/). The specification defines a set of custom resource definitions (CRD) that can create logical gateways and routes.
## Requirements
Your datacenter must meet the following requirements prior to configuring the Consul API Gateway:
- A Kubernetes cluster must be running
- Consul 1.11.0+
## Installation
1. Create a values file for your Consul server agents that contains the following parameters:
```yaml
global:
name: consul
image: 'hashicorp/consul:1.11.0'
tls:
enabled: true
connectInject:
enabled: true
controller:
enabled: true
```
1. Install Consul API Gateway using the standard Consul Helm chart and specify the custom values file.
```shell-session
helm install consul hashicorp/consul --version 0.37.0 -f values.yaml
```
The following components will be installed:
- Gateway controller
- CRDs required by the Kubernetes Gateway API specification
- `kustomize` manifests for completing the installation
1. After `helm` installs Consul API Gateway packages, issue the following commands to apply the API gateway to your Kubernetes cluster.
```shell-session
kubectl apply -k "github.com/hashicorp/consul-api-gateway/config/crd?ref=v0.1.0-techpreview"
kubectl apply -k "github.com/hashicorp/consul-api-gateway/config?ref=v0.1.0-techpreview"
```
## Usage
1. Verify that the [requirements](#requirements) have been met.
1. Verify that the Consul API Gateway software has been installed and applied (see [Installation](#installation)).
1. Configure the gateway, listener(s), and route(s) as described in [Configuration](#configuration)
1. Issue the `kubectl apply` command to implement the configurations, e.g.:
```shell-session
kubectl apply -f gateway-configuration.yaml
```
### Using the Consul API Gateway Binary
You can manually start the Consul API Gateway control plane server using the binary located in the home directory to issue the `server` command:
```shell-session
./consul-api-gateway server <options>
```
The following options are supported:
| Option | Description | Required | Default |
| ---------------------------------------------------------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | ----------------------------------------------- | --------------------------------------------------------- | ------ |
| `-ca-file` | String value that specifies the path to the CA for the Consul server. | Required | none |
| `-ca-secret` | String value that specifies the CA secret for the Consul server. | Required | none |
| `-ca-secret-namespace` &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; | String value that specifies the CA secret namespace for the Consul server. | Required | none |
| `-k8-context` | String value that specifies the Kubernetes context to use when starting the Consul server. | Optional | current context |
| `-k8-namespace` | String value that specifies the Kubernetes namespace to use when starting the Consul server. | Optional | `default` |
| `-log-json` | Boolean value that enables or disables JSON format for the log output. | Required | `false` |
| `-log-level` | String value that specifies the logging level. The following values are supported: <br/>- `trace` (highest level of detail) <br/>- `debug` <br/>- `info` <br/>- `warn` <br/>- `error` | context to use when starting the Consul server. | Required | `info` |
| `-metrics-port` | Integer value that specifies the port number for collecting metrics. | Optional | none |
| `-pprof` | Integer value that specifies the Go pprof port number for collecting metrics. | Optional | none |
| `-sds-server-host` | String value that specifies the host server for the secret discovery service (SDS). | Optional | `consul-api-gateway-controller.default.svc.cluster.local` |
| `-sds-server-host` | Integer value that specifies the port number for the secret discovery service (SDS). | Optional | `9090` |
You can also issue the `version` command to print the Consul API Gateway version to the console:
```shell-session
./consul-api-gateway version
consul-api-gateway 0.1.0-dev
```
## Configuration
Create the following artifacts to configure the API Gateway:
- [Gateway](#gateway): Defines the gateway properties, including listeners.
- [Listeners](#listeners): Defines listener properties, such as protocol, port, and namespace.
- [Routes](#routes): Specifies the path from the client to the listener.
### Gateway
The gateway object contains gateway listeners.
Add the `kind: Gateway` option to the configuration file to declare a gateway.
The following example creates a gateway called `example-gateway` that includes a listener called `https` (see Listeners for details about the `listener` configuration).
```yaml
apiVersion: gateway.networking.k8s.io/v1alpha2
kind: Gateway
metadata:
name: example-gateway
annotations:
'external-dns.alpha.kubernetes.io/hostname': DNS_HOSTNAME
spec:
gatewayClassName: default-consul-gateway-class
listeners:
- protocol: HTTPS
hostname: DNS_HOSTNAME
port: 443
name: https
allowedRoutes:
namespaces:
from: Same
tls:
certificateRefs:
- name: gateway-production-certificate
```
Refer to the Kubernetes Gateway API documentation for details about configuring gateways:
https://gateway-api.sigs.k8s.io/v1alpha2/references/spec/#gateway.networking.k8s.io/v1alpha2.Gateway
### Listener
Listeners are the logical endpoints bound to the gateway's addresses.
Add the `listener` object to the `gateway` configuration and specify the following properties to define a listener:
- `hostname`: Hostname specifies the virtual hostname to match for protocol types.
- `port`: Specifies the network port.
- `protocol`: Specifies the network protocol expected by the listener.
Refer to the Kubernetes Gateway API documentation for details about configuring listeners:
https://gateway-api.sigs.k8s.io/v1alpha2/references/spec/#gateway.networking.k8s.io/v1alpha2.Listener
In the example included the [Gateway](#gateway) description, a listener named `https` that listens over `HTTPS` is configured to listen on port `443`
### Route
Routes are independent configuration objects that are associated with a specific listener.
Use the `kind: HTTPRoute` option to declare a route and use the `spec` option to specify the route details.
The following example creates a route named `example-route` associated with a listener defined in `example-gateway`.
```yaml
apiVersion: gateway.networking.k8s.io/v1alpha2
kind: HTTPRoute
metadata:
name: example-route
spec:
parentRefs:
- name: example-gateway
rules:
- backendRefs:
- kind: Service
name: echo
port: 8080
```

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"title": "Transparent Proxy",
"href": "/docs/connect/transparent-proxy"
},
{
"title": "Consul API Gateway",
"path": "k8s/connect/api-gateway"
},
{
"title": "Ingress Gateways",
"path": "k8s/connect/ingress-gateways"