Here's the release [scalability validation report].

[SIG Scalability]: https://github.com/kubernetes/community/tree/master/sig-scalability
[scalability validation report]: https://github.com/kubernetes/sig-release/blob/master/releases/release-1.8/scalability_validation_report.md

### SIG Scheduling

- Added full cgroup v2 swap support for both `Limited` and `Unlimited` swap.
  
  When `LimitedSwap` is enabled the swap limit would be automatically calculated for
  Burstable QoS pods. For Best-Effort/Guaranteed QoS pods, swap would be disabled.
  

### Promoted endPort in Network Policy to Stable

Promoted `endPort` in [Network Policy](https://kubernetes.io/docs/concepts/services-networking/network-policies/#targeting-a-range-of-ports) to GA. Network Policy providers that support `endPort` field now can use it to specify a range of ports to apply a Network Policy. Previously, each Network Policy could only target a single port.

   ([#123341](https://github.com/kubernetes/kubernetes/pull/123341), [@neolit123](https://github.com/neolit123))
- kubectl `port-forward` over websockets (tunneling SPDY) can now be enabled using an `Alpha` feature flag environment variable: KUBECTL_PORT_FORWARD_WEBSOCKETS=true. The API Server being communicated to must *also* have an `Alpha` feature flag enabled: PortForwardWebsockets.

- github.com/hashicorp/serf: [v0.8.2](https://github.com/hashicorp/serf/tree/v0.8.2)
- github.com/jpillora/backoff: [v1.0.0](https://github.com/jpillora/backoff/tree/v1.0.0)
- github.com/jstemmer/go-junit-report: [v0.9.1](https://github.com/jstemmer/go-junit-report/tree/v0.9.1)
- github.com/kr/logfmt: [b84e30a](https://github.com/kr/logfmt/tree/b84e30a)
- github.com/kr/pty: [v1.1.1](https://github.com/kr/pty/tree/v1.1.1)