The open-source Ambassador 0.50 API gateway adds support for Server Name Indication (SNI), a much-requested feature from the community that allows the configuration of multiple TLS certificates to be served from a single ingress IP address. In this tutorial, we explore how multiple secure domains (e.g., https://www.datawire.io and https://www.getambassador.io.) can be provided by a single or load balanced Ambassador running within a Kubernetes cluster.
SNI Use Cases
In a nutshell (and with thanks to Wikipedia), SNI is an extension to the TLS protocol, which allows a client to indicate which hostname it is attempting to connect to at the start of the TCP handshaking process. This allows the server to present multiple certificates on the same IP address and TCP port number, which in turn enables the serving of multiple secure websites or API services without requiring all those sites to use the same certificate.