Authorization Provider Strategy for Application Registration

In the 1.5.x beta version of the Application Registration plugin, the feature was tightly coupled with OAuth2. Kong was the only available system of record (SoR) for application credentials and the OAuth configuration was done directly within the Application Registration plugin.

In the Kong Gateway 2.1.x version, authentication was decoupled from the Application Registration plugin. Support has been added for third-party OAuth2 providers. Developers have the flexibility to choose from either Kong or a third-party identity provider (IdP) as the system of record for application credentials. With third-party (external) OAuth2 support, developers can centralize application credential management with the supported identity provider of their choice.

In the Kong Gateway 2.2.1.x version and later, support has been added for the Key Authentication plugin to use with Kong as the system of record.

Supported Authentication Plugins

OAuth2 plugins for use with the Application Registration plugin:

When Kong Gateway is the system of record, the Application Registration plugin works in conjunction with the OAuth2 or the Key Authentication plugin.

Important: The OAuth2 plugin does not support hybrid mode. Since the Key Authentication plugin is using the `kong-oauth2` strategy and client ID credential, hybrid mode is also not supported for the Key Authentication plugin. If your organization uses hybrid mode, you must use an external identity provider and configure the OpenID Connect plugin.
When an external OAuth2 is the system of record, the Application Registration plugin works in conjunction with the OpenID Connect plugin.

The third-party authorization strategy (external-oauth2) applies to all applications across all Workspaces (Dev Portals) in a Kong Gateway cluster.

Authorization provider strategy configuration for Application Registration

The portal_app_auth configuration option must be set in kong.conf to enable the Dev Portal Application Registration plugin with your chosen authorization strategy. The default setting (kong-oauth2) accommodates the OAuth2 or Key Authentication plugins.

Available options:

kong-oauth2: Default. Kong Gateway is the system of record. The Application Registration plugin is used in conjunction with the OAuth2 or Key Authentication plugin. The kong-oauth2 option can only be used with classic (traditional) deployments. Because the OAuth2 plugin requires a database for every gateway instance, the kong-oauth2 option cannot be used with hybrid mode deployments.
external-oauth2: An external IdP is the system of record. The Portal Application Registration plugin is used in conjunction with the OIDC plugin. The external-oauth2 option can be used with any deployment type. The external-oauth2 option must be used with hybrid mode deployments because hybrid mode does not support kong-oauth2.

Set external portal authentication

If you are using an external IdP, follow these steps.

Open kong.conf.default and set the portal_app_auth option to your chosen strategy. The example configuration below switches from the default (kong-oauth2) to an external IdP (external-oauth2).

portal_app_auth = external-oauth2
         # Dev Portal application registration
         # auth provider and strategy. Must be set to configure
         # authentication in conjunction with the application_registration plugin.
         # Currently accepts kong-oauth2 or external-oauth2.

Restart your Kong Gateway instance.

Next Steps

Enable the Application Registration plugin on a Service.
Enable a supported authentication plugin on the same Service as the Application Registration plugin, as appropriate for your authorization strategy.

Strategy kong-oauth2:
- If using the kong-oauth2 authorization strategy with the OAuth2 plugin, configure the OAuth2 plugin on the same Service as the Application Registration plugin. You can use either the Kong Manager GUI or cURL commands as documented on the Plugin Hub. The OAuth2 plugin cannot be used in hybrid mode.
- If using the kong-oauth2 authorization strategy with key authentication, configure the Key Auth plugin on the same Service as the Application Registration plugin. You can use either the Kong Manager GUI or cURL commands as documented on the Plugin Hub. The Key Auth plugin cannot be used in hybrid mode.
Strategy external-oauth2:
1. If you plan to use external OAuth2, review the recommended workflows.
2. If using the third-party authorization strategy (external-oauth2), configure the OIDC plugin on the same Service as the Application Registration plugin. You can use the Kong Manager GUI or cURL commands as documented on the Plugin Hub. When your deployment is hybrid mode, the OIDC plugin must be configured to handle authentication for the Portal Application Registration plugin.
3. Configure the identity provider for your application, configure your application in Kong Gateway, and associate them with each other. See the Okta or the Azure setup examples.