Knative Serving provides components that enable:
Rapid deployment of serverless containers.
Autoscaling, including scaling pods down to zero.
Support for multiple networking layers, such as Ambassador, Contour, Kourier, Gloo, and Istio, for integration into existing environments.
Point-in-time snapshots of deployed code and configurations.
Knative Serving supports both HTTP and HTTPS - https://knative.dev/docs/serving/using-a-tls-cert/ networking protocols.
Knative Serving defines a set of objects as Kubernetes Custom Resource Definitions (CRDs). These objects are used to define and control how your serverless workload behaves on the cluster:
Service- https://github.com/knative/specs/blob/main/specs/serving/knative-api-specification-1.0.md#service: The
service.serving.knative.devresource automatically manages the whole lifecycle of your workload. It controls the creation of other objects to ensure that your app has a route, a configuration, and a new revision for each update of the service. Service can be defined to always route traffic to the latest revision or to a pinned revision.
Route- https://github.com/knative/specs/blob/main/specs/serving/knative-api-specification-1.0.md#route: The
route.serving.knative.devresource maps a network endpoint to one or more revisions. You can manage the traffic in several ways, including fractional traffic and named routes.
Configuration- https://github.com/knative/specs/blob/main/specs/serving/knative-api-specification-1.0.md#configuration: The
configuration.serving.knative.devresource maintains the desired state for your deployment. It provides a clean separation between code and configuration and follows the Twelve-Factor App methodology. Modifying a configuration creates a new revision.
Revision- https://github.com/knative/specs/blob/main/specs/serving/knative-api-specification-1.0.md#revision: The
revision.serving.knative.devresource is a point-in-time snapshot of the code and configuration for each modification made to the workload(Service).
Revisionsare immutable objects and can be retained for as long as useful. Knative Serving Revisions can be automatically scaled up and down according to incoming traffic. See Configuring the Autoscaler - https://knative.dev/docs/serving/autoscaling/ for more information.
To get started with Serving, check out one of the hello world - https://knative.dev/docs/samples/serving/ sample projects. These projects use the
Service resource, which manages all of the details for you.
Service resource, a deployed service will automatically have a matching route and configuration created. Each time the Service is updated, a new revision is created.
For more information on the resources and their interactions, see the Resource Types Overview - https://github.com/knative/specs/blob/main/specs/serving/overview.md in the Knative Serving repository.
More samples and demos
Debugging Knative Serving issues
- Debugging application issues - https://knative.dev/docs/serving/troubleshooting/debugging-application-issues/
Configuration and Networking
See the Knative Serving Issues - https://github.com/knative/serving/issues page for a full list of known issues.