mirror of https://github.com/hashicorp/consul
73 lines
4.1 KiB
Markdown
73 lines
4.1 KiB
Markdown
---
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layout: docs
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page_title: External <> Internal Services - Ingress Gateways
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sidebar_title: External <> Internal Services - Ingress Gateways
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description: >-
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An ingress gateway enables ingress traffic from services outside the Consul
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service mesh to services inside the Consul service mesh. This section details
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how to use Envoy and describes how you can plug in a gateway of your choice.
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---
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# Ingress Gateways
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-> **1.8.0+:** This feature is available in Consul versions 1.8.0 and newer.
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Ingress gateways enable ingress traffic from services outside the Consul
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service mesh to services inside the Consul service mesh. An ingress gateway is
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a type of proxy and must be registered as a service in Consul, with the
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[kind](/api/agent/service#kind) set to "ingress-gateway". They are an
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entrypoint for outside traffic and allow you to define what services should be
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exposed and on what port. You configure an ingress gateway by defining a set of
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[listeners](/docs/agent/config-entries/ingress-gateway#listeners) that each map
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to a set of backing
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[services](/docs/agent/config-entries/ingress-gateway#services).
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To enable easier service discovery, a new Consul [DNS
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subdomain](/docs/discovery/dns#ingress-service-lookups) is provided, on
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`<service>.ingress.<domain>`.
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For listeners with a
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[protocol](/docs/agent/config-entries/ingress-gateway#protocol) other than
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`tcp`, multiple services can be specified for a single listener. In this
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case, the ingress gateway relies on host/authority headers to decide the
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service that should receive the traffic. The host used to match traffic
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defaults to the [Consul DNS ingress
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subdomain](/docs/discovery/dns#ingress-service-lookups), but can be changed using
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the [hosts](/docs/agent/config-entries/ingress-gateway#hosts) field.
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![Ingress Gateway Architecture](/img/ingress-gateways.png)
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## Prerequisites
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Ingress gateways also require that your Consul datacenters are configured correctly:
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- You'll need to use Consul version 1.8.0 or newer.
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- Consul [Connect](/docs/agent/options#connect) must be enabled on the datacenter's Consul servers.
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- [gRPC](/docs/agent/options#grpc_port) must be enabled on all client agents.
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Currently, [Envoy](https://www.envoyproxy.io/) is the only proxy with ingress gateway capabilities in Consul.
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## Running and Using an Ingress Gateway
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For a complete example of how to allow external traffic inside your Consul service mesh,
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review the [ingress gateway tutorial](https://learn.hashicorp.com/tutorials/consul/service-mesh-ingress-gateways).
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## Ingress Gateway Configuration
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Ingress gateways are configured in service definitions and registered with Consul like other services, with two exceptions.
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The first is that the [kind](/api/agent/service#kind) must be "ingress-gateway". Second,
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the ingress gateway service definition may contain a `Proxy.Config` entry just like a
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Connect proxy service, to define opaque configuration parameters useful for the actual proxy software.
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For Envoy there are some supported [gateway options](/docs/connect/proxies/envoy#gateway-options) as well as
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[escape-hatch overrides](/docs/connect/proxies/envoy#escape-hatch-overrides).
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-> **Note:** If ACLs are enabled, ingress gateways must be registered with a token granting `service:write` for the ingress gateway's service name,
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`service:read` for all services in the ingress gateway's configuration entry, and `node:read` for all nodes of the services
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in the ingress gateway's configuration entry. These privileges authorize the token to route communications to other Connect services.
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If the Consul client agent on the gateway's node is not configured to use the default gRPC port, 8502, then the gateway's token
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must also provide `agent:read` for its node's name in order to discover the agent's gRPC port. gRPC is used to expose Envoy's xDS API to Envoy proxies.
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~> [Configuration entries](/docs/agent/config-entries) are global in scope. A configuration entry for a gateway name applies
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across all federated Consul datacenters. If ingress gateways in different Consul datacenters need to route to different
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sets of services within their datacenter then the ingress gateways **must** be registered with different names.
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