Self-hosted gateway overview

The self-hosted gateway is an optional, containerized version of the default managed gateway included in every API Management service. It's useful for scenarios such as placing gateways in the same environments where you host your APIs. Use the self-hosted gateway to improve API traffic flow and address API security and compliance requirements.

This article explains how the self-hosted gateway feature of Azure API Management enables hybrid and multi-cloud API management, presents its high-level architecture, and highlights its capabilities.

For an overview of the features across the various gateway offerings, see API gateway in API Management.

Hybrid and multi-cloud API management

The self-hosted gateway feature expands API Management support for hybrid and multi-cloud environments and enables organizations to efficiently and securely manage APIs hosted on-premises and across clouds from a single API Management service in Azure.

With the self-hosted gateway, customers have the flexibility to deploy a containerized version of the API Management gateway component to the same environments where they host their APIs. All self-hosted gateways are managed from the API Management service they're federated with, thus providing customers with the visibility and unified management experience across all internal and external APIs.

Each API Management service is composed of the following key components:

  • Management plane, exposed as an API, used to configure the service via the Azure portal, PowerShell, and other supported mechanisms.
  • Gateway (or data plane), which is responsible for proxying API requests, applying policies, and collecting telemetry
  • Developer portal used by developers to discover, learn, and onboard to use the APIs

By default, all these components are deployed in Azure, causing all API traffic (shown as solid black arrows on the following picture) to flow through Azure regardless of where backends implementing the APIs are hosted. The operational simplicity of this model comes at the cost of increased latency, compliance issues, and in some cases, extra data transfer fees.

API traffic flow without self-hosted gateways

Deploying self-hosted gateways into the same environments where the backend API implementations are hosted allows API traffic to flow directly to the backend APIs, which reduces latency, optimizes data transfer costs, and enables compliance while retaining the benefits of having a single point of management, observability, and discovery of all APIs within the organization regardless of where their implementations are hosted.

API traffic flow with self-hosted gateways

Packaging

The self-hosted gateway is available as a Linux-based Docker container image from the Microsoft Artifact Registry. It can be deployed to Docker, Kubernetes, or any other container orchestration solution running on a server cluster on premises, cloud infrastructure, or for evaluation and development purposes, on a personal computer.

Container images

We provide a variety of container images for self-hosted gateways to meet your needs:

Tag convention Recommendation Example Rolling tag Recommended for production
{major}.{minor}.{patch} Use this tag to always run the same version of the gateway 2.0.0 ✔️
v{major} Use this tag to always run a major version of the gateway with every new feature and patch. v2 ✔️
v{major}-preview Use this tag if you always want to run our latest preview container image. v2-preview ✔️
latest Use this tag if you want to evaluate the self-hosted gateway. latest ✔️

You can find a full list of available tags here.

Use of tags in our official deployment options

Our deployment options in the Azure portal use the v2 tag that allows customers to use the most recent version of the self-hosted gateway v2 container image with all feature updates and patches.

Note

We provide the command and YAML snippets as reference, feel free to use a more specific tag if you wish to.

When installing with our Helm chart, image tagging is optimized for you. The Helm chart's application version pins the gateway to a given version and doesn't rely on latest.

Learn more on how to install an API Management self-hosted gateway on Kubernetes with Helm.

Risk of using rolling tags

Rolling tags are tags that are potentially updated when a new version of the container image is released. This allows container users to receive updates to the container image without having to update their deployments.

This means that you can potentially run different versions in parallel without noticing it, for example when you perform scaling actions once v2 tag was updated.

Example - v2 tag was released with 2.0.0 container image, but when 2.1.0 will be released, the v2 tag will be linked to the 2.1.0 image.

Important

Consider using a specific version tag in production to avoid unintentional upgrade to a newer version.

Connectivity to Azure

Self-hosted gateways require outbound TCP/IP connectivity to Azure on port 443. Each self-hosted gateway must be associated with a single API Management service and is configured via its management plane. A self-hosted gateway uses connectivity to Azure for:

  • Reporting its status by sending heartbeat messages every minute
  • Regularly checking for (every 10 seconds) and applying configuration updates whenever they're available
  • Sending metrics to Azure Monitor, if configured to do so
  • Sending events to Application Insights, if set to do so

Important

Support for Azure API Management self-hosted gateway version 0 and version 1 container images is ending on 1 October 2023, along with its corresponding Configuration API v1. Use our migration guide to use self-hosted gateway v2.0.0 or higher with Configuration API v2. Learn more in our deprecation documentation

FQDN dependencies

To operate properly, each self-hosted gateway needs outbound connectivity on port 443 to the following endpoints associated with its cloud-based API Management instance:

Description Required for v1 Required for v2 Notes
Hostname of the configuration endpoint <apim-service-name>.management.azure-api.cn <apim-service-name>.configuration.azure-api.cn
Public IP address of the API Management instance ✔️ ✔️ IP addresses of primary location is sufficient.
Public IP addresses of Azure Storage service tag ✔️ Optional1 IP addresses must correspond to primary location of API Management instance.
Hostname of Azure Blob Storage account ✔️ Optional1 Account associated with instance (<blob-storage-account-name>.blob.core.chinacloudapi.cn)
Hostname of Azure Table Storage account ✔️ Optional1 Account associated with instance (<table-storage-account-name>.table.core.chinacloudapi.cn)
Endpoints for Azure Application Insights integration Optional2 Optional2 Minimal required endpoints are:
  • rt.services.visualstudio.com:443
  • dc.services.visualstudio.com:443
  • {region}.livediagnostics.monitor.azure.com:443
Learn more in Azure Monitor docs
Endpoints for Event Hubs integration Optional2 Optional2 Learn more in Azure Event Hubs docs
Endpoints for external cache integration Optional2 Optional2 This requirement depends on the external cache that is being used

1 Only required in v2 when API inspector or quotas are used in policies.
2 Only required when feature is used and requires public IP address, port and hostname information.

Important

  • DNS hostnames must be resolvable to IP addresses and the corresponding IP addresses must be reachable.
  • The associated storage account names are listed in the service's Network connectivity status page in the Azure portal.
  • Public IP addresses underlying the associated storage accounts are dynamic and can change without notice.

Connectivity failures

When connectivity to Azure is lost, the self-hosted gateway is unable to receive configuration updates, report its status, or upload telemetry.

The self-hosted gateway is designed to "fail static" and can survive temporary loss of connectivity to Azure. It can be deployed with or without local configuration backup. With configuration backup, self-hosted gateways regularly save a backup copy of the latest downloaded configuration on a persistent volume attached to their container or pod.

When configuration backup is turned off and connectivity to Azure is interrupted:

  • Running self-hosted gateways will continue to function using an in-memory copy of the configuration
  • Stopped self-hosted gateways won't be able to start

When configuration backup is turned on and connectivity to Azure is interrupted:

  • Running self-hosted gateways will continue to function using an in-memory copy of the configuration
  • Stopped self-hosted gateways will be able to start using a backup copy of the configuration

When connectivity is restored, each self-hosted gateway affected by the outage will automatically reconnect with its associated API Management service and download all configuration updates that occurred while the gateway was "offline".

Security

Limitations

The following functionality found in the managed gateways is not available in the self-hosted gateways:

  • TLS session resumption.
  • Client certificate renegotiation. To use client certificate authentication, API consumers must present their certificates as part of the initial TLS handshake. To ensure this behavior, enable the Negotiate Client Certificate setting when configuring a self-hosted gateway custom hostname (domain name).

Transport Layer Security (TLS)

Important

This overview is only applicable to the self-hosted gateway v1 & v2.

Supported protocols

The self-hosted gateway provides support for TLS v1.2 by default.

Customers using custom domains can enable TLS v1.0 and/or v1.1 in the control plane.

Available cipher suites

Important

This overview is only applicable to the self-hosted gateway v2.

The self-hosted gateway uses the following cipher suites for both client and server connections:

  • TLS_AES_256_GCM_SHA384
  • TLS_CHACHA20_POLY1305_SHA256
  • TLS_AES_128_GCM_SHA256
  • TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384
  • TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384
  • TLS_DHE_RSA_WITH_AES_256_GCM_SHA384
  • TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305_SHA256
  • TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305_SHA256
  • TLS_DHE_RSA_WITH_CHACHA20_POLY1305_SHA256
  • TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256
  • TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256
  • TLS_DHE_RSA_WITH_AES_128_GCM_SHA256
  • TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA384
  • TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384
  • TLS_DHE_RSA_WITH_AES_256_CBC_SHA256
  • TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA256
  • TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256
  • TLS_DHE_RSA_WITH_AES_128_CBC_SHA256
  • TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA
  • TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA
  • TLS_DHE_RSA_WITH_AES_256_CBC_SHA
  • TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA
  • TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA
  • TLS_DHE_RSA_WITH_AES_128_CBC_SHA
  • TLS_RSA_WITH_AES_256_GCM_SHA384
  • TLS_RSA_WITH_AES_128_GCM_SHA256
  • TLS_RSA_WITH_AES_256_CBC_SHA256
  • TLS_RSA_WITH_AES_128_CBC_SHA256
  • TLS_RSA_WITH_AES_256_CBC_SHA
  • TLS_RSA_WITH_AES_128_CBC_SHA

Managing cipher suites

As of v2.1.1 and above, you can manage the ciphers that are being used through the configuration:

  • net.server.tls.ciphers.allowed-suites allows you to define a comma-separated list of ciphers to use for the TLS connection between the API client and the self-hosted gateway.
  • net.client.tls.ciphers.allowed-suites allows you to define a comma-separated list of ciphers to use for the TLS connection between the self-hosted gateway and the backend.

Next steps