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This document describes the steps required to secure communication between Envoy and Contour.
The outcome of this is that we will have two Secrets available in the
contourin order for this to work. This is currently hardcoded by Contour.
Note that both Secrets contain a copy of the CA certificate bundle under the
ca.crt data key.
contour certgen --kube --secrets-format=compactfor you.
contour certgen --kubelocally.
Be very careful with your production certificates!
This is intended as an example to help you get started. For any real deployment, you should carefully manage all the certificates and control who has access to them. Make sure you don’t commit them to any git repositories either.
First, we need to generate a keypair:
$ openssl req -x509 -new -nodes \ -keyout certs/cakey.pem -sha256 \ -days 1825 -out certs/cacert.pem \ -subj "/O=Project Contour/CN=Contour CA"
Then, the new CA key will be stored in
certs/cakey.pem and the cert in
Next, we need to generate a keypair for Contour. First, we make a new private key:
$ openssl genrsa -out certs/contourkey.pem 2048
Then, we create a CSR and have our CA sign the CSR and issue a certificate.
This uses the file _integration/cert-contour.ext, which ensures that at least one of the valid names of the certificate is the bareword
This is required for the handshake to succeed, as
contour bootstrap configures Envoy to pass this as the SNI server name for the connection.
$ openssl req -new -key certs/contourkey.pem \ -out certs/contour.csr \ -subj "/O=Project Contour/CN=contour" $ openssl x509 -req -in certs/contour.csr \ -CA certs/cacert.pem \ -CAkey certs/cakey.pem \ -CAcreateserial \ -out certs/contourcert.pem \ -days 1825 -sha256 \ -extfile _integration/cert-contour.ext
At this point, the contour certificate and key are in the files
Next, we generate a keypair for Envoy:
$ openssl genrsa -out certs/envoykey.pem 2048
Then, we generate a CSR and have the CA sign it:
$ openssl req -new -key certs/envoykey.pem \ -out certs/envoy.csr \ -subj "/O=Project Contour/CN=envoy" $ openssl x509 -req -in certs/envoy.csr \ -CA certs/cacert.pem \ -CAkey certs/cakey.pem \ -CAcreateserial \ -out certs/envoycert.pem \ -days 1825 -sha256 \ -extfile _integration/cert-envoy.ext
Like the Contour certificate, this CSR uses the file _integration/cert-envoy.ext. However, in this case, there are no special names required.
Next, we create the required Secrets in the target Kubernetes cluster:
$ kubectl create secret -n projectcontour generic contourcert \ --from-file=tls.key=./certs/contourkey.pem \ --from-file=tls.crt=./certs/contourcert.pem \ --from-file=ca.crt=./certs/cacert.pem \ --save-config $ kubectl create secret -n projectcontour generic envoycert \ --from-file=tls.key=./certs/envoykey.pem \ --from-file=tls.crt=./certs/envoycert.pem \ --from-file=ca.crt=./certs/cacert.pem \ --save-config
Note that we don’t put the CA key into the cluster, there’s no reason for that to be there, and that would create a security problem.
Eventually the certificates that Contour and Envoy use will need to be rotated. The following steps can be taken to replace the certificates that Contour and Envoy are using:
The secrets can be updated in-place by running:
$ kubectl create secret -n projectcontour generic contourcert \ --from-file=tls.key=./certs/contourkey.pem \ --from-file=tls.crt=./certs/contourcert.pem \ --from-file=ca.crt=./certs/cacert.pem \ --dry-run -o json \ | kubectl apply -f - $ kubectl create secret -n projectcontour generic envoycert \ --from-file=tls.key=./certs/envoykey.pem \ --from-file=tls.crt=./certs/envoycert.pem \ --from-file=ca.crt=./certs/cacert.pem \ --dry-run -o json \ | kubectl apply -f -
There are few preconditions that need to be met before Envoy can automatically reload certificate and key files:
contour bootstrapusing the
--resources-dirargument, see examples/contour/03-envoy.yaml
When using the built-in Contour certificate generation, the following steps can be used:
kubectl delete job contour-certgen -n projectcontour
Once this process is done, the certificates will be present as Secrets in the
projectcontour namespace, as required by