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.

 
---
title: service graph of the demo app with a builtin gateway on front
---
flowchart LR
  subgraph edge-gateway
    gw0(/ :8080)
  end
  demo-app(demo-app :5000)
  redis(redis :6379)
  gw0 --> demo-app 
  demo-app --> redis

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. This may not be the case if the Kubernetes cluster is running locally with kind or k3d.

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

Read more about the different types of gateways in the managing ingress traffic docs.
Learn about setting up observability to get full end to end visibility of your mesh.