* Implement CanMount() for gfsMounter for linux ([#36686](https://github.com/kubernetes/kubernetes/pull/36686), [@rkouj](https://github.com/rkouj))
* Better messaging for missing volume binaries on host ([#36280](https://github.com/kubernetes/kubernetes/pull/36280), [@rkouj](https://github.com/rkouj))

* Clean up the kube-proxy container image by removing unnecessary packages and files. ([#42090](https://github.com/kubernetes/kubernetes/pull/42090), [@timstclair](https://github.com/timstclair))
* Better compat with very old iptables (e.g. CentOS 6) ([#37594](https://github.com/kubernetes/kubernetes/pull/37594), [@thockin](https://github.com/thockin))

### Scheduler

- We’re working to simplify the Windows node join experience with better scripts and kubeadm. Scripts and doc updates are still in the works, but some of the needed improvements are included in 1.15.  These include:

### Provider-specific Notes

#### Various

   Core changes:

  * Support for load balancers with source ranges

#### AWS

Core changes:

  * Support for ELBs with complex configurations: better subnet selection with
multiple subnets, and internal ELBs
  * Support for VPCs with private dns names
  * Multiple fixes to EBS volume mounting code for robustness, and to support

* Change docker metrics to conform metrics guidelines and using histogram for better aggregation. ([#72323](https://github.com/kubernetes/kubernetes/pull/72323), [@danielqsj](https://github.com/danielqsj))
    * The following metrics are deprecated, and will be removed in a future release:

  you want to set the equivalent of any of the `--iptables-xxx` options.)
  
  As this code is still very new, it has not been heavily optimized yet;
  while it is expected to _eventually_ have better performance than the
  iptables backend, very little performance testing has been done so far. ([#121046](https://github.com/kubernetes/kubernetes/pull/121046), [@danwinship](https://github.com/danwinship))

- Service session affinity timeout tests are no longer required for Kubernetes network plugin conformance due to variations in existing implementations. New conformance tests will be developed to better express conformance in future releases. ([#112806](https://github.com/kubernetes/kubernetes/pull/112806), [@dcbw](https://github.com/dcbw)) [SIG Architecture, Network and Testing]

  * Fix the Kubelet PLEG update timestamp to better reflect the health of the component when the container runtime request hangs. ([#45496](https://github.com/kubernetes/kubernetes/pull/45496), [@andyxning](https://github.com/andyxning))