TLS Termination and Enabling HTTPS

TLS encryption is one of the basic requirements of having a secure system. Ambassador Edge Stack automatically enables TLS termination/HTTPs , making TLS encryption easy and centralizing TLS termination for all of your services in Kubernetes.

While this automatic certificate management in the Ambassador Edge Stack helps simply TLS configuration in your cluster, the Open-Source Ambassador API Gateway still requires you provide your own certificate to enable TLS.

The following will walk you through the process of enabling TLS with a self-signed certificate created with the openssl utility.

Note these instructions also work if you would like to provide your own certificate to the Ambassador Edge Stack.

Prerequisites

This guide requires you have the following installed:

  • A Kubernetes cluster v1.11 or newer
  • The Kubernetes command-line tool, kubectl
  • openssl

Install Ambassador Edge Stack

Install Ambassador Edge Stack in Kubernetes.

Create a Self-Signed Certificate

OpenSSL is a tool that allows us to create self-signed certificates for opening a TLS encrypted connection. The openssl command below will create a create a certificate and private key pair that Ambassador can use for TLS termination.

  • Create a private key and certificate.

    openssl req -x509 -newkey rsa:4096 -keyout key.pem -out cert.pem -subj '/CN=ambassador-cert' -nodes

    The above command will create a certificate and private key with the common name ambassador. Since this certificate is self-signed and only used for testing, the other information requested can be left blank.

  • Verify the key.pem and cert.pem files were created

    ls *.pem
    cert.pem key.pem

Store the Certificate and Key in a Kubernetes Secret

Ambassador Edge Stack dynamically loads TLS certificates by reading them from Kubernetes secrets. Use kubectl to create a tls secret to hold the pem files we created above.

kubectl create secret tls tls-cert --cert=cert.pem --key=key.pem

Tell Ambassador Edge Stack to Use this Secret for TLS Termination

Now that we have stored our certificate and private key in a Kubernetes secret named tls-cert, we need to tell Ambassador Edge Stack to use this certificate for terminating TLS on a domain. A Host is used to tell Ambassador which certificate to use for TLS termination on a domain.

Create the following Host to have Ambassador use the Secret we created above for terminating TLS on all domains.

---
apiVersion: getambassador.io/v2
kind: Host
metadata:
name: wildcard-host
spec:
hostname: "*"
acmeProvider:
authority: none
tlsSecret:
name: tls-cert
selector:
matchLabels:
hostname: wildcard-host

Note: If running multiple instances of ambassador in one cluster remember to include ambassador_id property in the spec, must be an array of id(s).

Apply the Host configured above with kubectl:

kubectl apply -f wildcard-host.yaml

Ambassador is now configured to listen for TLS traffic on port 8443 and terminate TLS using the self-signed certificate we created.

Send a Request Over HTTPS

We can now send encrypted traffic over HTTPS.

First, make sure the Ambassador service is listening on 443 and forwarding to port 8443. Verify this with kubectl:

kubectl get service ambassador -o yaml
apiVersion: v1
kind: Service
...
spec:
ports:
- name: http
port: 80
protocol: TCP
targetPort: 8080
- name: https
port: 443
protocol: TCP
targetPort: 8443
...

If the output to the kubectl command is not similar to the example above, edit the Ambassador service to add the https port.

After verifying Ambassador Edge Stack is listening on port 443, send a request to your backend service with curl:

curl -Lk https://{{AMBASSADOR_IP}}/backend/
{
"server": "trim-kumquat-fccjxh8x",
"quote": "Abstraction is ever present.",
"time": "2019-07-24T16:36:56.7983516Z"
}

Note: Since we are using a self-signed certificate, you must set the -k flag in curl to disable hostname validation.

Next Steps

This guide walked you through how to enable basic TLS termination in Ambassador Edge Stack using a self-signed certificate for simplicity.

Get a Valid Certificate from a Certificate Authority

While a self-signed certificate is a simple and quick way to get Ambassador Edge Stack to terminate TLS, it should not be used by production systems. In order to serve HTTPS traffic without being returned a security warning, you will need to get a certificate from an official Certificate Authority like Let's Encrypt.

With the Ambassador Edge Stack, this can be simply done by requesting a certificate using the built in ACME support

For the Open-Source API Gateway, Jetstack's cert-manager provides a simple way to manage certificates from Let's Encrypt. See our documentation for more information on how to use cert-manager with Ambassador Edge Stack .

Enable Advanced TLS options

Ambassador Edge Stack exposes configuration for many more advanced options around TLS termination, origination, client certificate validation, and SNI support. See the full TLS reference for more information.

Questions?

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