- Using `--log-file` is known to be problematic in 1.15. This presents as things being logged multiple times to the same file. The behaviour and details of this issue, as well as some preliminary attempts at fixing it are documented [here](https://github.com/kubernetes/kubernetes/issues/78734#issuecomment-501372131)

## Urgent Upgrade Notes

### (No, really, you MUST read this before you upgrade)

#### API Machinery

## **Notable Features**

- A new `TaintNodesByCondition` admission plugin taints newly created Node objects as "not ready", to fix a race condition that could cause pods to be scheduled on new nodes before their taints were updated to accurately reflect their reported conditions. This admission plugin is enabled by default if the `TaintNodesByCondition` feature is enabled. ([#73097](https://github.com/kubernetes/kubernetes/pull/73097),...

  
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* Kubernetes v1.3 introduces a new Attach/Detach Controller. This controller manages attaching and detaching of volumes on-behalf of nodes.  ([#26351](https://github.com/kubernetes/kubernetes/pull/26351), [@saad-ali](https://github.com/saad-ali))

**Note**: This only impacts the cluster if the ServiceAccount admission plugin is used (most cluster should have this on by default as recommended in https://kubernetes.io/docs/reference/access-authn-authz/admission-controllers/#serviceaccount), the `kubernetes.io/enforce-mountable-secrets` annotation is used by a service account (this annotation is not added by default), and Pods are using ephemeral containers.