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