Updating from a Private CA Certificate to a Common Certificate
We can change from a private certificate to a common, or non-private, certificate. The steps involved are outlined below.
1. Create/update the certificate secret resource
We will use kubenetes-replicator to get replicas of the secret
cat <<EOF | kubectl apply -f -
apiVersion: v1
kind: Secret
metadata:
  name: tls-rancher-ingress
  namespace: cattle-system
  annotations:
    replicator.v1.mittwald.de/replicate-from: default/example-cert
data: {}
2. Delete the CA certificate secret resource
We will delete the tls-ca secret in the cattle-system namespace as it is no longer needed. We can also optionally save a copy of the tls-ca secret if desired.
To save the existing secret.
kubectl -n cattle-system get secret tls-ca -o yaml > tls-ca.yaml
To delete the existing tls-ca secret.
kubectl -n cattle-system delete secret tls-ca
3. Reconfigure the Rancher deployment
helm upgrade rancher rancher-stable/rancher -n cattle-system \
    --set hostname=rancher.example.com \
    --set ingress.tls.source=secret \
    --set privateCA=false