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Add a builtin gateway

To get traffic from outside your mesh inside it (North/South) with Kuma you can use a builtin gateway.

In the quickstart, traffic was only able to get in the mesh by port-forwarding to an instance of an app inside the mesh. In production, you typically set up a gateway to receive traffic external to the mesh. In this guide you will add a built-in gateway in front of the demo-app service and expose it publicly.

Prerequisites

  • Completed quickstart to set up a zone control plane with demo application

Start a gateway

Create a MeshGatewayInstance

A MeshGatewayInstance configures the pods that will run the gateway.

Create it by running:

echo "
apiVersion: kuma.io/v1alpha1
kind: MeshGatewayInstance
metadata:
  name: edge-gateway
  namespace: kuma-demo
spec:
  replicas: 1
  serviceType: LoadBalancer
" | kubectl apply -f -

The Kubernetes cluster needs to support LoadBalancer for this to work.

If you are running minikube you will want to open a tunnel with minikube tunnel -p mesh-zone.

You may not have support for LoadBalancer if you are running locally with kind or k3d. One option for kind is kubernetes-sigs/cloud-provider-kind may be helpful.

Define a listener using MeshGateway

MeshGateway defines listeners for the gateway.

Define a single HTTP listener on port 8080:

echo "
apiVersion: kuma.io/v1alpha1
kind: MeshGateway
mesh: default
metadata:
  name: my-gateway
spec:
  selectors:
    - match:
        kuma.io/service: edge-gateway_kuma-demo_svc
  conf:
    listeners:
      - port: 8080
        protocol: HTTP
        tags:
          port: http-8080
" | kubectl apply -f -

Notice how the selector selects the kuma.io/service tag of the previously defined MeshGatewayInstance.

Now look at the pods running in the namespace by running:

kubectl get pods -n kuma-demo

Observe the gateway pod:

NAME                            READY   STATUS    RESTARTS   AGE
redis-5fdb98848c-5tw62          2/2     Running   0          5m5s
demo-app-c7cd6588b-rtwlj        2/2     Running   0          5m5s
edge-gateway-66c76fd477-ncsp5   1/1     Running   0          18s

Retrieve the public URL for the gateway with:

export PROXY_IP=$(kubectl get svc --namespace kuma-demo edge-gateway -o jsonpath='{.status.loadBalancer.ingress[0].ip}')
echo $PROXY_IP

Check the gateway is running:

curl -v ${PROXY_IP}:8080

Which outputs:

*   Trying 127.0.0.1:8080...
* Connected to 127.0.0.1 (127.0.0.1) port 8080
> GET / HTTP/1.1
> Host: 127.0.0.1:8080
> User-Agent: curl/8.4.0
> Accept: */*
>
< HTTP/1.1 404 Not Found
< content-length: 62
< content-type: text/plain
< vary: Accept-Encoding
< date: Fri, 09 Feb 2024 10:07:26 GMT
< server: Kuma Gateway
<
This is a Kuma MeshGateway. No routes match this MeshGateway!

Notice the gateway says that there are no routes configured.

Define a route using MeshHTTPRoute

MeshHTTPRoute defines HTTP routes inside your service mesh. Attach a route to an entire gateway or to a single listener by using targetRef.kind: MeshGateway

echo "
apiVersion: kuma.io/v1alpha1
kind: MeshHTTPRoute
metadata:
 name: edge-gateway-route
 namespace: kuma-system 
 labels:
   kuma.io/mesh: default
spec:
 targetRef:
   kind: MeshGateway
   name: my-gateway
 to:
 - targetRef:
     kind: Mesh
   rules:
   - matches:
     - path:
         type: PathPrefix
         value: "/"
     default:
       backendRefs:
       - kind: MeshService
         name: demo-app_kuma-demo_svc_5000
" | kubectl apply -f -

Now try to reach our gateway again:

curl -v ${PROXY_IP}:8080

which outputs:

*   Trying 127.0.0.1:8080...
* Connected to 127.0.0.1 (127.0.0.1) port 8080
> GET / HTTP/1.1
> Host: 127.0.0.1:8080
> User-Agent: curl/8.4.0
> Accept: */*
>
< HTTP/1.1 403 Forbidden
< content-length: 19
< content-type: text/plain
< date: Fri, 09 Feb 2024 10:10:16 GMT
< server: Kuma Gateway
< x-envoy-upstream-service-time: 24
<
* Connection #0 to host 127.0.0.1 left intact
RBAC: access denied%

Notice the forbidden error. This is because the quickstart has very restrictive permissions as defaults. Therefore, the gateway doesn’t have permissions to talk to the demo-app service.

To fix this, add a MeshTrafficPermission:

echo "
apiVersion: kuma.io/v1alpha1
kind: MeshTrafficPermission
metadata:
  namespace: kuma-system 
  name: demo-app
spec:
  targetRef:
    kind: MeshService
    name: demo-app_kuma-demo_svc_5000
  from:
    - targetRef:
        kind: MeshSubset
        tags: 
          kuma.io/service: edge-gateway_kuma-demo_svc 
      default:
        action: Allow
" | kubectl apply -f -

Check it works with:

curl -XPOST -v ${PROXY_IP}:8080/increment

Now returns a 200 OK response:

*   Trying 127.0.0.1:8080...
* Connected to 127.0.0.1 (127.0.0.1) port 8080
> POST /increment HTTP/1.1
> Host: 127.0.0.1:8080
> User-Agent: curl/8.4.0
> Accept: */*
>
< HTTP/1.1 200 OK
< x-powered-by: Express
< content-type: application/json; charset=utf-8
< content-length: 42
< etag: W/"2a-gDIArbqhTz783Hls/ysnTwRRsmQ"
< date: Fri, 09 Feb 2024 10:24:33 GMT
< x-envoy-upstream-service-time: 6
< server: Kuma Gateway
<
* Connection #0 to host 127.0.0.1 left intact
{"counter":3265,"zone":"local","err":null}

Securing your public endpoint with a certificate

The application is now exposed to a public endpoint thanks to the gateway. We will now add TLS to our endpoint.

Create a certificate

Create a self-signed certificate:

openssl req -x509 -nodes -days 365 -newkey rsa:2048 -keyout tls.key -out tls.crt -subj "/CN=${PROXY_IP}"

echo "
apiVersion: v1
kind: Secret
metadata:
  name: my-gateway-certificate
  namespace: kuma-system 
  labels:
    kuma.io/mesh: default
data:
  value: "$(cat tls.key tls.crt | base64)"
type: system.kuma.io/secret
" | kubectl apply -f -

Now update the gateway to use this certificate:

echo "
apiVersion: kuma.io/v1alpha1
kind: MeshGateway
mesh: default
metadata:
  name: my-gateway
spec:
  selectors:
    - match:
        kuma.io/service: edge-gateway_kuma-demo_svc
  conf:
    listeners:
      - port: 8080
        protocol: HTTPS
        tls:
          mode: TERMINATE
          certificates:
            - secret: my-gateway-certificate
        tags:
          port: http-8080
" | kubectl apply -f -

Check the call to the gateway:

curl -X POST -v --insecure https://${PROXY_IP}:8080/increment

Which should output a successful call and indicate TLS is being used:

*   Trying 127.0.0.1:8080...
* Connected to 127.0.0.1 (127.0.0.1) port 8080
* ALPN: curl offers h2,http/1.1
* (304) (OUT), TLS handshake, Client hello (1):
* (304) (IN), TLS handshake, Server hello (2):
* (304) (IN), TLS handshake, Unknown (8):
* (304) (IN), TLS handshake, Certificate (11):
* (304) (IN), TLS handshake, CERT verify (15):
* (304) (IN), TLS handshake, Finished (20):
* (304) (OUT), TLS handshake, Finished (20):
* SSL connection using TLSv1.3 / AEAD-CHACHA20-POLY1305-SHA256
* ALPN: server accepted h2
* Server certificate:
*  subject: CN=127.0.0.1
*  start date: Feb  9 10:49:13 2024 GMT
*  expire date: Feb  8 10:49:13 2025 GMT
*  issuer: CN=127.0.0.1
*  SSL certificate verify result: self signed certificate (18), continuing anyway.
* using HTTP/2
* [HTTP/2] [1] OPENED stream for https://127.0.0.1:8080/increment
* [HTTP/2] [1] [:method: POST]
* [HTTP/2] [1] [:scheme: https]
* [HTTP/2] [1] [:authority: 127.0.0.1:8080]
* [HTTP/2] [1] [:path: /increment]
* [HTTP/2] [1] [user-agent: curl/8.4.0]
* [HTTP/2] [1] [accept: */*]
> POST /increment HTTP/2
> Host: 127.0.0.1:8080
> User-Agent: curl/8.4.0
> Accept: */*
>
< HTTP/2 200
< x-powered-by: Express
< content-type: application/json; charset=utf-8
< content-length: 42
< etag: W/"2a-BZZq4nXMINsG8HLM31MxUPDwPXk"
< date: Fri, 09 Feb 2024 13:41:11 GMT
< x-envoy-upstream-service-time: 19
< server: Kuma Gateway
< strict-transport-security: max-age=31536000; includeSubDomains
<
* Connection #0 to host 127.0.0.1 left intact
{"counter":3271,"zone":"local","err":null}%

Note that we’re using --insecure as we have used a self-signed certificate.

Next steps