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src/kubernetes-ingress-controller/concepts/gateway-api.md
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| --- | ||
| title: Gateway API | ||
| alpha: true | ||
| --- | ||
|
|
||
| [Gateway API](https://gateway-api.sigs.k8s.io/) is a set of resources for | ||
| configuring networking in Kubernetes. It expands on Ingress to configure | ||
| additional types of routes (TCP, UDP, and TLS in addition to HTTP/HTTPS), | ||
| support backends other than Service, and manage the proxies that implement | ||
| routes. | ||
|
|
||
| Gateway API and Kong's implementation of Gateway API are both under active | ||
| development. Features and implementation specifics will change before their | ||
| initial general availability release. | ||
|
|
||
| ## Gateway management | ||
|
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| A [Gateway resource](https://gateway-api.sigs.k8s.io/concepts/api-overview/#gateway) | ||
| describes an application or cluster feature that can handle Gateway API routing | ||
| rules, directing inbound traffic to Services following the rules provided. For | ||
| Kong's implementation, a Gateway corresponds to a Kong Deployment managed by | ||
| the ingress controller. | ||
|
|
||
| Typically, Gateway API implementations manage the resources associated with a | ||
| Gateway on behalf of users: creating a Gateway resource will trigger automatic | ||
| provisioning of Deployments/Services/etc. with configuration matching the | ||
| Gateway's listeners and addresses. The Kong alpha implementation does _not_ | ||
| automatically manage Gateway provisioning: you must create the Kong and ingress | ||
| controller Deployment and proxy Service yourself following the [Gateway | ||
| installation guide](/kubernetes-ingress-controller/{{page.kong_version}}/guides/using-gateway-api). | ||
|
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||
| Because the Kong Deployment and its configuration are not managed | ||
| automatically, listener and address configuration are not set for you. You must | ||
| configure your Deployment and Service to match your Gateway's configuration. | ||
| For example, with this Gateway: | ||
|
|
||
| ``` | ||
| apiVersion: gateway.networking.k8s.io/v1beta1 | ||
| kind: Gateway | ||
| metadata: | ||
| name: example | ||
| spec: | ||
| gatewayClassName: kong | ||
| listeners: | ||
| - name: proxy | ||
| port: 80 | ||
| protocol: HTTP | ||
| - name: proxy-ssl | ||
| port: 443 | ||
| protocol: HTTPS | ||
| - name: proxy-tcp-9901 | ||
| port: 9901 | ||
| protocol: TCP | ||
| - name: proxy-udp-9902 | ||
| port: 9902 | ||
| protocol: UDP | ||
| - name: proxy-tls-9903 | ||
| port: 9903 | ||
| protocol: TLS | ||
| ``` | ||
| requires a proxy Service that includes all the requested listener ports: | ||
|
|
||
| ``` | ||
| apiVersion: v1 | ||
| kind: Service | ||
| metadata: | ||
| name: proxy | ||
| spec: | ||
| ports: | ||
| - port: 80 | ||
| protocol: TCP | ||
| targetPort: 8000 | ||
| - port: 443 | ||
| protocol: TCP | ||
| targetPort: 8443 | ||
| - port: 9901 | ||
| protocol: TCP | ||
| targetPort: 9901 | ||
| - port: 9902 | ||
| protocol: UDP | ||
| targetPort: 9902 | ||
| - port: 9903 | ||
| protocol: TCP | ||
| targetPort: 9903 | ||
| ``` | ||
| and matching Kong `proxy_listen` configuration in the container environment: | ||
|
|
||
| ``` | ||
| KONG_PROXY_LISTEN="0.0.0.0:8000 reuseport backlog=16384, 0.0.0.0:8443 http2 ssl reuseport backlog=16384 http2" | ||
| KONG_STREAM_LISTEN="0.0.0.0:9901 reuseport backlog=16384, 0.0.0.0:9902 reuseport backlog=16384 udp", 0.0.0.0:9903 reuseport backlog=16384 ssl" | ||
| ``` | ||
| The Helm chart manages both of these for you from the `proxy` configuration | ||
| block: | ||
|
|
||
| ``` | ||
| proxy: | ||
| http: | ||
| enabled: true | ||
| servicePort: 80 | ||
| containerPort: 8000 | ||
| tls: | ||
| enabled: true | ||
| servicePort: 443 | ||
| containerPort: 8443 | ||
| stream: [] | ||
| - containerPort: 9901 | ||
| servicePort: 9901 | ||
| protocol: TCP | ||
| - containerPort: 9902 | ||
| servicePort: 9902 | ||
| protocol: UDP | ||
| - containerPort: 9903 | ||
| servicePort: 9903 | ||
| protocol: TCP | ||
| parameters: | ||
| - "ssl" | ||
| ``` | ||
| Ports missing appropriate Kong-side configuration will result in an error | ||
| condition in the Gateway's status: | ||
|
|
||
| ``` | ||
| message: no Kong listen with the requested protocol is configured for the | ||
| requested port | ||
| reason: PortUnavailable | ||
| ``` | ||
|
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| ## Listener compatibility and handling multiple Gateways | ||
|
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| During the alpha, without automatic Gateway Deployment provisioning, Kong's | ||
| implementation can only handle a single GatewayClass, and only one Gateway in | ||
| that GatewayClass. Although the controller will attempt to handle configuration | ||
| from all Gateways in its GatewayClass, adding more than one Gateway is not yet | ||
| supported and will likely result in unexpected behavior. If you wish to use | ||
| multiple Gateways, define multiple GatewayClasses and install a separate | ||
| Deployment for each. | ||
|
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| For background, Gateway API allows implementations to collapse compatible | ||
| listens and Gateways: | ||
|
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| > An implementation MAY group Listeners by Port and then collapse each group of | ||
| > Listeners into a single Listener if the implementation determines that the | ||
| > Listeners in the group are “compatible”. An implementation MAY also group | ||
| > together and collapse compatible Listeners belonging to different Gateways. | ||
| Compatibility means that listeners can coexist: for example, two HTTP listens | ||
| can coexist on the same port because Gateways can still route inbound requests | ||
| using the HTTP `Host` header, whereas two TCP listens cannot coexist on the | ||
| same port because the port is the only characteristic that can select between | ||
| TCP routes. | ||
|
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||
| If there is a conflict between listeners on a Gateway, the controller will mark | ||
| the conflict in the Gateway status and not add routes that require the | ||
| conflicting listener. The controller cannot, however, perform these same | ||
| validity checks across separate Gateway resources. |
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