Knative Serving release v0.13.2

Meta

Minimum Kubernetes version remains 1.15

This is NOT a change from 0.12, however, with the adoption of Conversion webhooks this is no longer something that may be overridden without consequence.
The target minimum version for our next (0.14) release will be Kubernetes 1.16.

Deprecation of the Alpha and Beta Serving APIs

The v1 APIs are now available in every supported version of Knative, and our controllers are now consuming v1 themselves.
We will continue to ship the deprecated APIs for 9 months (6 releases), so these will be removed in the 0.19 release.

We now rely on CRD Conversion webhooks

We take advantage of this long-awaited Beta+ feature in 1.15+ to manage converting between v1alpha1, v1beta1, and v1 types.

Autoscaling

• Probe and forward traffic to non-ready pods (#6695 thanks @markusthoemmes)
• gRPC e2e autoscaling test (#6778, thanks @tanzeeb, @shashwathi)
• We no longer restrict min target at 1, permitting correct target utilization with CC=1 (#6951 thanks @vagababov)
• Ignore young pods from metric computation (#6649, #6626, thanks @vagababov)
• Metric Reporting Refactoring
  • Activator #6804, #6843 (thanks @markusthoemmes)
  • Autoscaler (#6774,#6707, #6712), QP #6852 (thanks @vagababov)
• Cleanups and improvements (logging, metrics, unit and e2e tests, etcs); many PRs (thanks @jpeach, @MIBc, @taragu, @markusthoemmes, @vagababov)

Core API

• We’ve adopted generated reconcilers to help minimize the boilerplate in our controllers (thanks @n3wscott, @mattmoor, @shashwathi #6993 #6973 #6969 #6952)
• We’re removed the serving stats reporter that was reporting some nonsensical metrics (thanks @mattmoor #6939)
• Webhook certificates now rotate (thanks @mpetason knative/pkg#1101)
• The validating admission webhook will now apply the correct defaults (thanks @itsmurugappan #6938)
• We’ve started our journey of actually deprecating the v1alpha1 APIs for the resources Service, Configuration, Revision and Route.
  • The controllers for these resources use the v1 APIs (thanks @dprotaso, @mattmoor #6933 #6949 #6950 #6957 #6958 #6959 #6960)
  • Thanks for the conversion webhook framework @dprotaso (knative/pkg#993)
  • Note: v1alpha1 will remain the storage version until we provide guidance on how to migrate the storage version to v1 - see #6726
  • Our current plan is remove v1alpha1 and v1beta1 APIs in 0.19
  • HPA auto scaling using Revision metrics (concurrency & requests per second) now use v1 APIs (thanks @dprotaso #6957).
    • Consuming revision metrics for the resource version v1alpha1 is deprecated and will be removed in the next release (0.14)

Networking

• Deprecate the istio.sidecar.includeOutboundIPRanges in config-network #6597 (thanks @nak3)
• Avoid unconditionally reconciling the Gateways on deletion #6934 (thanks @ZhiminXiang)
• Remove "internal" in class name of Certificates #6887 (thanks @ZhiminXiang)
• Wrong revision is picked up for traffic target marked as "latest" #6876 (thanks @taragu)
• Fix Ready -> NotReady- > Ready flip flops in Ingress Prober #6648 (thanks @JRBANCEL)
• Clean up orphaned VirtualService when migrating from Istio KIngress to other KIngress #6570 (thanks @nak3)
• Avoid specifying IngressTLS before Certificate reports Ready. #6870 (thanks @mattmoor)
• queue-proxy to returns 504 on connect timeouts #6859 (thanks @vagababov)
• KIngress to disallow ServiceNamespace that differs from its own #6868 (thanks @MIBc)
• Fix name collision when having two Route with name ${route} and ${route}-mesh #6362 (thanks @sreddy)
• Route reconciler to separate cluster local Ingress rules and external domain rules to avoid ClusterLocal special-casing in KIngress implementation #6727 (thanks @tcnghia, @andrew-su)
• Correctly set the network prober User-Agent #6644 (thanks @jpeach)
• gRPC, AutoTLS, and KIngress testing (thanks @ZhiminXiang, @tanzeeb, @sreddy, @rmoe, andrew-su@)