--- 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 ``` 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`                         | 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:
- `trace` (highest level of detail)
- `debug`
- `info`
- `warn`
- `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 ```