Add HTTP Routing to an Application

This topic tells you how to configure a deployment so that you can route HTTP or HTTPS traffic to a deployed application.

Many applications, such as web applications, serve traffic using HTTP and HTTPS. To route this traffic to a deployed application, the Tanzu provided spring-dev.tanzu.vmware.com and spring-prod.tanzu.vmware.com Profiles include the k8sgateway.tanzu.vmware.com Capability that works in conjunction with the multicloud-ingress.tanzu.vmware.com Trait defined as part of a custom networking profile.

When a Space is created from these Profiles, these Capabilities use an httproute resource to create a DNS based Global Service Load Balancer (GSLB) and route ingress traffic from the GLSB to a Kubernetes Gateway in the Space, then to the corresponding Kubernetes services that are created for the application.

This httproute resource is manually defined in your application before deployment. This how-to will walk you through how to create this resource to route traffic to a deployed application.

Before you begin

Before defining a httproute resource, you must have:

Created a Space using Profiles that require the k8sgateway.tanzu.vmware.com Capability (from spring-dev.tanzu.vmware.com and spring-prod.tanzu.vmware.com Tanzu provided Profiles) and multicloud-ingress.tanzu.vmware.com Trait (from custom networking profile).

An example Space is provided in the Getting Started guide.
An application that you want to deploy to the Space that is expecting HTTP traffic to be routed to it. As a guide, this topic provides example httproute resources for two sample applications for different scenarios.
Initialized the ContainerApp from the source code for the application.

Overview

This how-to will provide steps to create httproute resources for two sample applications:

Spring Music:

A simple sample application that routes traffic directly to the Kubernetes services.
Where for Dinner:

Used in the Getting Started Guide which includes the use of Spring Cloud Gateway. The httproute routes traffic to the Spring Cloud Gateway, which then routes traffic to the correct Kubernetes service based on the route.

Before exploring httproute for example apps, here is how to create a basic httproute resource and explore the values.

For the traffic to be routed to your application, you need to create the manifest after the ContainerApp has been initialized so that it can be deployed with tanzu deploy. To do this, do the following:

Navigate to the .tanzu/config directory within the your repository that was created when you initialized an app with the tanzu app init.
```
cd .tanzu/config
```

Create a file named k8sGatewayRoutes.yaml using the following template

apiVersion: gateway.networking.k8s.io/v1beta1
kind: HTTPRoute
metadata:
  name: <APP-NAME>-route
  annotations:
    healthcheck.gslb.tanzu.vmware.com/service: <APP-NAME>
    healthcheck.gslb.tanzu.vmware.com/path: <HEALTHCHECK-PATH>
    healthcheck.gslb.tanzu.vmware.com/port: <HEALTHCHECK-PORT>
spec:
  parentRefs:
  - group: gateway.networking.k8s.io
    kind: Gateway
    name: default-gateway
    sectionName: http-<APP-HOSTNAME> #use https for TLS
  rules:
  - backendRefs:
    - group: ""
      kind: Service
      name: <APP-NAME>
      port: <APP-PORT>
      weight: 1
    matches:
    - path:
        type: PathPrefix
        value: <APP-PATH>

Where:

Variable	Description	Example
`APP-NAME`	The name of the application specified by the `tanzu deploy` command	helloworld
`HEALTHCHECK-PATH`	The path that the application provides the health check service on	`/`
`HEALTHCHECK-PORT`	The port that the application provides the health check service on	8080
`APP-HOSTNAME`	The hostname that the GSLB uses in combination with the domain from the `multicloud-ingress.tanzu.vmware.com` Trait configuration to create the DNS record. Must be prefixed with `http` or `https`. For example, if this is `http-helloworld` and the `multicloud-ingress.tanzu.vmware.com` Trait is `tanzu.com`, the resulting DNS record is `helloworld.tanzu.com`.	http-helloworld
`APP-PORT`	The port that the Kubernetes services is listening on for HTTP requests	80
`APP-PATH`	The path for the application	`/`

Create an HTTP Route manifest

Spring Music: is a simple application that requires traffic to be routed in to the Space from the multicloud-ingress, directly to the Kubernetes service, and then to the pods hosting the service. The httproute resource for this sample app is as follows:

apiVersion: gateway.networking.k8s.io/v1beta1
kind: HTTPRoute
metadata:
  name: spring-music-route
  annotations:
    healthcheck.gslb.tanzu.vmware.com/service: spring-music
    healthcheck.gslb.tanzu.vmware.com/path: /
    healthcheck.gslb.tanzu.vmware.com/port: "8080"
spec:
  parentRefs:
  - group: gateway.networking.k8s.io
    kind: Gateway
    name: default-gateway
    sectionName: http-spring-music
  rules:
  - backendRefs:
    - group: ""
      kind: Service
      name: spring-music
      port: 8080
      weight: 1
    matches:
    - path:
        type: PathPrefix
        value: /

Where for Dinner sample

Where for Dinner: uses Spring Cloud Gateway. The httproute routes traffic to the Spring Cloud Gateway, which then routes traffic to the correct Kubernetes service based on the route. The httproute resource for this sample app is as follows:

apiVersion: gateway.networking.k8s.io/v1beta1
kind: HTTPRoute
metadata:
  name: where-for-dinner-scg-route
  annotations:
    healthcheck.gslb.tanzu.vmware.com/service: spring-cloud-gateway
    healthcheck.gslb.tanzu.vmware.com/path: /
    healthcheck.gslb.tanzu.vmware.com/port: "80"
spec:
  parentRefs:
  - group: gateway.networking.k8s.io
    kind: Gateway
    name: default-gateway
    sectionName: http-where-for-dinner
  rules:
  - backendRefs:
    - group: ""
      kind: Service
      name: spring-cloud-gateway
      port: 80
      weight: 1
    matches:
    - path:
        type: PathPrefix
        value: /