Add to release notes

docs/releases/1.17-NOTES.md

@@ -71,6 +71,8 @@
 
 * Support for the "Legacy" etcd provider has been deprecated. It will not be supported for Kubernetes 1.18 or later. To migrate to the default "Manager" etcd provider see the [etcd migration documentation](../etcd3-migration.md).
 
+* The default StorageClass `gp2` is no longer the default, replaced by SotrageClass `kops-ssd-1-17`.
+
 # Known Issues
 
 * Kops 1.17.0-beta.1 included an update for AWS IAM Authenticator to 0.5.0.
@@ -79,6 +81,11 @@
   The workaround is to specify the old 0.4.0 image with `spec.authentication.aws.image=602401143452.dkr.ecr.us-west-2.amazonaws.com/amazon/aws-iam-authenticator:v0.4.0`.
   For the 1.17.0 release, this change was rolled back, and the AWS IAM authenticator defaults to version 0.4.0
 
+* Kops 1.17.0 includes a new StorageClass `kops-ssd-1-17` which is set as the default via the annotation `"storageclass.beta.kubernetes.io/is-default-class":"true"`.
+  If you have modified the previous `gp2` StorageClass, it could conflict with the defaulting behavior.
+  To resolve, patch the `gp2` StorageClass to have the annotation `"storageclass.beta.kubernetes.io/is-default-class":"false"`, which aligns with a patch to Kops 1.17.1 as well.
+  `kubectl patch storageclass.storage.k8s.io/gp2 --patch '{"metadata": {"annotations": {"storageclass.beta.kubernetes.io/is-default-class": "false"}}}'`
+
 # Full change list since 1.16.0 release
 
 ## 1.16.0-alpha.1 to 1.17.0-alpha.1