Ingress is a shared abstraction that can be implemented by many providers (Nginx, ALBs, Traefik, HAProxy, etc). It is specifically an abstraction over a fairly simple HTTP reverse proxy that can do routing based on hostnames and path prefixes. Because it has to be a shared thing, that means it’s been awkward to handle configuration of provider-specific settings. Some teams on the provider side have decided the benefits of a shared abstraction are not worth the complexities of implementation and have made their own things, so far Contour and Traefik have both named them IngressRoute but there is no connection other than similar naming.

If you want to keep using Traefik Proxy, high availability for Let’s Encrypt can be achieved by using a Certificate Controller such as Cert-Manager. When using Cert-Manager to manage certificates, it creates secrets in your namespaces that can be referenced as TLS secrets in your ingress objects. When using the Traefik Kubernetes CRD Provider, unfortunately Cert-Manager cannot yet interface directly with the CRDs. A workaround is to enable the Kubernetes Ingress provider to allow Cert-Manager to create ingress objects to complete the challenges. Please note that this still requires manual intervention to create the certificates through Cert-Manager, but once the certificates are created, Cert-Manager keeps them renewed.