Secure Gateways
4 minute read
This guide will help you get started using secure Gateways. The guide uses a self-signed CA, so it should be used for testing and demonstration purposes only.
Prerequisites
- OpenSSL to generate TLS assets.
Installation
Follow the steps from the Quickstart Guide to install Envoy Gateway and the example manifest. Before proceeding, you should be able to query the example backend using HTTP.
TLS Certificates
Generate the certificates and keys used by the Gateway to terminate client TLS connections.
Create a root certificate and private key to sign certificates:
openssl req -x509 -sha256 -nodes -days 365 -newkey rsa:2048 -subj '/O=example Inc./CN=example.com' -keyout example.com.key -out example.com.crt
Create a certificate and a private key for www.example.com:
openssl req -out www.example.com.csr -newkey rsa:2048 -nodes -keyout www.example.com.key -subj "/CN=www.example.com/O=example organization"
openssl x509 -req -days 365 -CA example.com.crt -CAkey example.com.key -set_serial 0 -in www.example.com.csr -out www.example.com.crt
Store the cert/key in a Secret:
kubectl create secret tls example-cert --key=www.example.com.key --cert=www.example.com.crt
Update the Gateway from the Quickstart guide to include an HTTPS listener that listens on port 443 and references the
example-cert Secret:
kubectl patch gateway eg --type=json --patch '[{
"op": "add",
"path": "/spec/listeners/-",
"value": {
"name": "https",
"protocol": "HTTPS",
"port": 443,
"tls": {
"mode": "Terminate",
"certificateRefs": [{
"kind": "Secret",
"group": "",
"name": "example-cert",
}],
},
},
}]'
Verify the Gateway status:
kubectl get gateway/eg -o yaml
Testing
Clusters without External LoadBalancer Support
Get the name of the Envoy service created the by the example Gateway:
export ENVOY_SERVICE=$(kubectl get svc -n envoy-gateway-system --selector=gateway.envoyproxy.io/owning-gateway-namespace=default,gateway.envoyproxy.io/owning-gateway-name=eg -o jsonpath='{.items[0].metadata.name}')
Port forward to the Envoy service:
kubectl -n envoy-gateway-system port-forward service/${ENVOY_SERVICE} 8443:443 &
Query the example app through Envoy proxy:
curl -v -HHost:www.example.com --resolve "www.example.com:8443:127.0.0.1" \
--cacert example.com.crt https://www.example.com:8443/get
Clusters with External LoadBalancer Support
Get the External IP of the Gateway:
export GATEWAY_HOST=$(kubectl get gateway/eg -o jsonpath='{.status.addresses[0].value}')
Query the example app through the Gateway:
curl -v -HHost:www.example.com --resolve "www.example.com:443:${GATEWAY_HOST}" \
--cacert example.com.crt https://www.example.com/get
Multiple HTTPS Listeners
Create a TLS cert/key for the additional HTTPS listener:
openssl req -out foo.example.com.csr -newkey rsa:2048 -nodes -keyout foo.example.com.key -subj "/CN=foo.example.com/O=example organization"
openssl x509 -req -days 365 -CA example.com.crt -CAkey example.com.key -set_serial 0 -in foo.example.com.csr -out foo.example.com.crt
Store the cert/key in a Secret:
kubectl create secret tls foo-cert --key=foo.example.com.key --cert=foo.example.com.crt
Create another HTTPS listener on the example Gateway:
kubectl patch gateway eg --type=json --patch '[{
"op": "add",
"path": "/spec/listeners/-",
"value": {
"name": "https-foo",
"protocol": "HTTPS",
"port": 443,
"hostname": "foo.example.com",
"tls": {
"mode": "Terminate",
"certificateRefs": [{
"kind": "Secret",
"group": "",
"name": "foo-cert",
}],
},
},
}]'
Update the HTTPRoute to route traffic for hostname foo.example.com to the example backend service:
kubectl patch httproute backend --type=json --patch '[{
"op": "add",
"path": "/spec/hostnames/-",
"value": "foo.example.com",
}]'
Verify the Gateway status:
kubectl get gateway/eg -o yaml
Follow the steps in the Testing section to test connectivity to the backend app through both Gateway
listeners. Replace www.example.com with foo.example.com to test the new HTTPS listener.
Cross Namespace Certificate References
A Gateway can be configured to reference a certificate in a different namespace. This is allowed by a ReferenceGrant created in the target namespace. Without the ReferenceGrant, a cross-namespace reference is invalid.
Before proceeding, ensure you can query the HTTPS backend service from the Testing section.
To demonstrate cross namespace certificate references, create a ReferenceGrant that allows Gateways from the “default” namespace to reference Secrets in the “envoy-gateway-system” namespace:
$ cat <<EOF | kubectl apply -f -
apiVersion: gateway.networking.k8s.io/v1alpha2
kind: ReferenceGrant
metadata:
name: example
namespace: envoy-gateway-system
spec:
from:
- group: gateway.networking.k8s.io
kind: Gateway
namespace: default
to:
- group: ""
kind: Secret
EOF
Delete the previously created Secret:
kubectl delete secret/example-cert
The Gateway HTTPS listener should now surface the Ready: False status condition and the example HTTPS backend should
no longer be reachable through the Gateway.
kubectl get gateway/eg -o yaml
Recreate the example Secret in the envoy-gateway-system namespace:
kubectl create secret tls example-cert -n envoy-gateway-system --key=www.example.com.key --cert=www.example.com.crt
Update the Gateway HTTPS listener with namespace: envoy-gateway-system, for example:
$ cat <<EOF | kubectl apply -f -
apiVersion: gateway.networking.k8s.io/v1beta1
kind: Gateway
metadata:
name: eg
spec:
gatewayClassName: eg
listeners:
- name: http
protocol: HTTP
port: 80
- name: https
protocol: HTTPS
port: 443
tls:
mode: Terminate
certificateRefs:
- kind: Secret
group: ""
name: example-cert
namespace: envoy-gateway-system
EOF
The Gateway HTTPS listener status should now surface the Ready: True condition and you should once again be able to
query the HTTPS backend through the Gateway.
Lastly, test connectivity using the above Testing section.
Clean-Up
Follow the steps from the Quickstart Guide to uninstall Envoy Gateway and the example manifest.
Delete the Secrets:
kubectl delete secret/example-cert
kubectl delete secret/foo-cert
Next Steps
Checkout the Developer Guide to get involved in the project.
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