## Changes by Kind

### Bug or Regression

- Fix a bug when the hostname label of a node does not match the node name, pods bound to a PV with nodeAffinity using the hostname may be scheduled to the wrong node or experience scheduling failures. ([#127584](https://github.com/kubernetes/kubernetes/pull/127584), [@AxeZhan](https://github.com/AxeZhan)) [SIG Scheduling and Storage]

    *   SignatureRunner is now supported for models with no signatures.

[kubernetes.tar.gz](https://storage.googleapis.com/kubernetes-release/release/v1.4.0/kubernetes.tar.gz) | `6cf3d78230f7659b87fa399a56a7aaed1fde6a73be9d05e25feedacfbd8d5a16`

## Major Themes

- **Simplified User Experience**
  - Easier to get a cluster up and running (eg: `kubeadm`, intra-cluster bootstrapping)
  - Easier to understand a cluster (eg: API audit logs, server-based API defaults)
- **Stateful Application Support**

* `federation/deploy/deploy.sh` was an interim solution introduced in Kubernetes v1.4 to simplify the federation control plane deployment experience. Now that we have `kubefed`, we are deprecating `deploy.sh` scripts. ([#38902](https://github.com/kubernetes/kubernetes/pull/38902), [@madhusudancs](https://github.com/madhusudancs))


### Cluster Provisioning Scripts

- Added the `DetectCacheInconsistency` feature gate, allowing the API server to periodically verify consistency between its `cache` and `etcd`. Detected inconsistencies reported...

				if took > maxRefreshDurationSecondsForLog {
					// Log if we took a lot of time.
					logger.Info("Site replication healing refresh took %.2fs", took)
				}

				// wait for 200 millisecond, if we are experience lot of I/O
				waitForLowIO(runtime.GOMAXPROCS(0), 200*time.Millisecond, currentHTTPIO)
			}
			healTimer.Reset(siteHealTimeInterval)

		case <-ctx.Done():
			return
		}
	}
}

### Deprecation

- Aborting the drain command in a list of nodes will be deprecated. The new behavior will make the drain command go through all nodes even if one or more nodes failed during the drain. For now, users can try such experience by enabling --ignore-errors flag. ([#98203](https://github.com/kubernetes/kubernetes/pull/98203), [@yuzhiquan](https://github.com/yuzhiquan))

- If a conflict occurs when creating an object with `generateName`, the server now returns an "AlreadyExists" error with a retry option. ([#1...

For 1.13 SIG Cluster Lifecycle is pleased to announce the long awaited promotion of kubeadm to stable GA, and the promotion of kubeadm’s configuration API to `v1beta1`.
In this release the SIG again focused on further improving the user experience on cluster creation and also fixing a number of bugs and other assorted improvements.

Some notable changes in kubeadm since Kubernetes 1.12:

- 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: