Knative

Kubernetes doesn't have built-in support for FaaS. As a result, many solutions were developed by the community for the ecosystem. The goal of Knative is to provide building blocks that multiple FaaS solutions can utilize without reinventing the wheel.

But that's not all! Knative also offers the unique capability of scaling long-running services all the way down to zero. This is a big deal. There are many use cases where you may prefer to have a long-running service that can handle a lot of requests coming its way in rapid succession. In those situations, it is not the best approach to fire a new function instance per request. But, when there is no traffic coming in, it's great to scale the service to zero instances, pay nothing, and leave more capacity for other services that may need more resources at that time. Knative supports other important use cases including load balancing based on percentages, load balancing based on metrics, blue-green deployments...