Project: Kuma (Orchestration & Management / Service Mesh)
File: gateway.md

When kuma-dp is deployed, both ingress and egress connections are intercepted by Envoy, probably with mTLS applied. We want to enable users to access the Mesh with Ingress Gateway, like this: ``` --(Traffic from the Internet)--> Ingress Gateway --> Gateway's Envoy --(Traffic encrypted by Kuma)--> App's Envoy --> App ``` This means that only outbound traffic of Ingress Gateway should be intercepted by Envoy. There are several options how to model this Right now we require valid inbound interface in Dataplane entity. We can introduce new field which can be defined instead of `inbound`. ```yaml type: Dataplane mesh: demo name: gateway-01 networking: gateway: tags: service: gateway outbound: interface: :33033 service: database interface: :44044 service: user ``` We can also introduce brand new entity. ```yaml type: Gateway mesh: demo name: gateway-01 tags: service: gateway networking: outbound: interface: :33033 service: database interface: :44044 service: user ``` While `Gateway` entity seems like a better option UX-wise it gives us a couple challenges with implementation. Gateway is a special case of Dataplane, so all features for Dataplane should be available for Gateway. Should gateway appear in `get dataplanes`? If not, we need to duplicate `get dataplanes` and `inspect dataplanes` (+ API, + core entities, + logic) to provide statistics. If we include it into `get dataplanes` and GET request, should PUT/DELETE requests to Dataplanes operate on Gateways? We use Dataplane elements across the CP logic. We would need to convert Gateway into Dataplane on the fly, which brings another question: Can mesh+name be the same for a Gateway as for a Dataplane? It's potentially error prone. When dealing with Dataplanes we would always have to think about Gateways. We can miss including Gateway in some logic. Since we don't specify `Dataplane` objects manually, we can just mark Pod as Gateway with annotation `kuma.io/gateway=true`. Inbounds traffic to apps in pods marked with this annotation won't be intercepted by

Injector will detect this annotation and set empty `-b` argument to . We could also introduce more specific configuration with ports that should be intercepted `kuma.io/inboundPorts=1234,5678`. On both K8S and Universal, Kong is deployed into the mesh as any other service. First we deploy Kong and Kuma-DP next to Kong with following DP definition ```yaml type: Dataplane mesh: demo name: kong-01 networking: gateway: tags: service: kong outbound: interface: :44044 service: admin interface: :44043 service: frontend ``` Next, we configure Kong with services and routes. ```yaml services: name: admin url: http://localhost:44044 routes: name: admin-route paths: /user name: frontend url: http://localhost:44043 routes: name: frontend-route paths: /frontend ``` Since such dataplane won't expose inbound listener, we pass the traffic to the listener exposed by Kong itself. First we annotate of the Kong with annotation `kuma.io/gateway=true` like this ```yaml apiVersion: apps/v1 kind: Deployment metadata: labels: app: ingress-kong name: ingress-kong namespace: kong spec: replicas: 1 selector: matchLabels: app: ingress-kong template: metadata: annotations: kuma.io/gateway: enabled ``` Then we configure Kong via K8S Ingress CRD ```yaml apiVersion: extensions/v1beta1 kind: Ingress metadata: name: demo spec: rules: http: paths: path: /admin backend: serviceName: admin servicePort: 80 http: paths: path: /frontend backend: serviceName: frontend servicePort: 80 ``` Note: Kong Ingress Controller does load balancing by itself, then it send a request to selected Endpoint with `Host` header of the service. This breaks transparent proxying since Kuma for now works with L4 and does not recognise `Host` header. Once Kuma works with L7 it can rebalance it with proper endpoint. There is an option to turn off load balancing by Kong for given service, to do that `Service` to which traffic is directed should be annotated with `ingress.kubernetes.io/service-upstream=true` . We picked option with Dataplane entity, we won't introduce new entity. Additionally, there should be an option to filter gateways in kumactl and HTTP API. Right now we want to focus on integrating with current API Gateways, meaning Kuma won't work as Gateway itself.