The Securing Gateways with HTTPS task describes how to configure HTTPS ingress access to an HTTP service. This example describes how to configure HTTPS ingress access to an HTTPS service, i.e., configure an ingress gateway to perform SNI passthrough, instead of TLS termination on incoming requests.
The example HTTPS service used for this task is a simple NGINX server. In the following steps you first deploy the NGINX service in your Kubernetes cluster. Then you configure a gateway to provide ingress access to the service via host nginx.example.com.
Create a root certificate and private key to sign the certificate for your services:
mkdir example_certs
openssl req -x509 -sha256 -nodes -days 365 -newkey rsa:2048 -subj '/O=example Inc./CN=example.com' -keyout example_certs/example.com.key -out example_certs/example.com.crtCreate a certificate and a private key for nginx.example.com:
openssl req -out example_certs/nginx.example.com.csr -newkey rsa:2048 -nodes -keyout example_certs/nginx.example.com.key -subj "/CN=nginx.example.com/O=some organization"
openssl x509 -req -sha256 -days 365 -CA example_certs/example.com.crt -CAkey example_certs/example.com.key -set_serial 0 -in example_certs/nginx.example.com.csr -out example_certs/nginx.example.com.crtCreate a Kubernetes Secret to hold the server’s certificate.
kubectl create secret tls nginx-server-certs \
--key example_certs/nginx.example.com.key \
--cert example_certs/nginx.example.com.crt
Create a configuration file for the NGINX server:
cat <<\EOF > ./nginx.conf
events {
}
http {
log_format main '$remote_addr - $remote_user [$time_local] $status '
'"$request" $body_bytes_sent "$http_referer" '
'"$http_user_agent" "$http_x_forwarded_for"';
access_log /var/log/nginx/access.log main;
error_log /var/log/nginx/error.log;
server {
listen 443 ssl;
root /usr/share/nginx/html;
index index.html;
server_name nginx.example.com;
ssl_certificate /etc/nginx-server-certs/tls.crt;
ssl_certificate_key /etc/nginx-server-certs/tls.key;
}
}
EOF
Create a Kubernetes ConfigMap to hold the configuration of the NGINX server:
kubectl create configmap nginx-configmap --from-file=nginx.conf=./nginx.conf
Deploy the NGINX server:
cat <<EOF | kubectl apply -f -
apiVersion: v1
kind: Service
metadata:
name: my-nginx
labels:
run: my-nginx
spec:
ports:
- port: 443
protocol: TCP
selector:
run: my-nginx
---
apiVersion: apps/v1
kind: Deployment
metadata:
name: my-nginx
spec:
selector:
matchLabels:
run: my-nginx
replicas: 1
template:
metadata:
labels:
run: my-nginx
sidecar.istio.io/inject: "true"
spec:
containers:
- name: my-nginx
image: nginx
ports:
- containerPort: 443
volumeMounts:
- name: nginx-config
mountPath: /etc/nginx
readOnly: true
- name: nginx-server-certs
mountPath: /etc/nginx-server-certs
readOnly: true
volumes:
- name: nginx-config
configMap:
name: nginx-configmap
- name: nginx-server-certs
secret:
secretName: nginx-server-certs
EOF
To test that the NGINX server was deployed successfully, send a request to the server from its sidecar proxy without checking the server’s certificate (use the -k option of curl). Ensure that the server’s certificate is printed correctly, i.e., common name (CN) is equal to nginx.example.com.
kubectl exec "$(kubectl get pod -l run=my-nginx -o jsonpath={.items..metadata.name})" -c istio-proxy -- curl -sS -v -k --resolve nginx.example.com:443:127.0.0.1 https://nginx.example.com
Define a Gateway exposing port 443 with passthrough TLS mode. This instructs the gateway to pass the ingress traffic “as is”, without terminating TLS:
kubectl apply -f - <<EOF
apiVersion: networking.istio.io/v1alpha3
kind: Gateway
metadata:
name: mygateway
spec:
selector:
istio: ingressgateway # use istio default ingress gateway
servers:
- port:
number: 443
name: https
protocol: HTTPS
tls:
mode: PASSTHROUGH
hosts:
- nginx.example.com
EOFConfigure routes for traffic entering via the Gateway:
kubectl apply -f - <<EOF
apiVersion: networking.istio.io/v1alpha3
kind: VirtualService
metadata:
name: nginx
spec:
hosts:
- nginx.example.com
gateways:
- mygateway
tls:
- match:
- port: 443
sniHosts:
- nginx.example.com
route:
- destination:
host: my-nginx
port:
number: 443
EOF
export INGRESS_HOST=$(kubectl -n "$INGRESS_NS" get service "$INGRESS_NAME" -o jsonpath='{.status.loadBalancer.ingress[0].ip}')
export INGRESS_PORT=$(kubectl -n "$INGRESS_NS" get service "$INGRESS_NAME" -o jsonpath='{.spec.ports[?(@.name=="http2")].port}')
export SECURE_INGRESS_PORT=$(kubectl -n "$INGRESS_NS" get service "$INGRESS_NAME" -o jsonpath='{.spec.ports[?(@.name=="https")].port}')
export TCP_INGRESS_PORT=$(kubectl -n "$INGRESS_NS" get service "$INGRESS_NAME" -o jsonpath='{.spec.ports[?(@.name=="tcp")].port}')
Access the NGINX service from outside the cluster. Note that the correct certificate is returned by the server and it is successfully verified (SSL certificate verify ok is printed).
curl -v --resolve "nginx.example.com:$SECURE_INGRESS_PORT:$INGRESS_HOST" --cacert example_certs/example.com.crt "https://nginx.example.com:$SECURE_INGRESS_PORT"
Output
* Server certificate:
* subject: CN=nginx.example.com; O=some organization
* start date: Feb 11 10:59:38 2024 GMT
* expire date: Feb 10 10:59:38 2025 GMT
* common name: nginx.example.com (matched)
* issuer: O=example Inc.; CN=example.com
* SSL certificate verify ok.
...
< HTTP/1.1 200 OK
< Server: nginx/1.25.3
...
<html>
<head>
<title>Welcome to nginx!</title># Delete the gateway configuration and route:
kubectl delete gateway mygateway
kubectl delete virtualservice nginx
# Remove the NGINX resources and configuration file:
kubectl delete secret nginx-server-certs
kubectl delete configmap nginx-configmap
kubectl delete service my-nginx
kubectl delete deployment my-nginx
# rm ./nginx.conf
# Delete the certificates and keys:
rm -rf ./example_certs