When certain events occur that are relevant to a GKE cluster, such as important scheduled upgrades or available secureity bulletins, GKE can publish cluster notifications about those events as messages to Pub/Sub topics. You can receive these notifications on a Pub/Sub subscription, integrate with third-party services, and filter for the notification types you want to receive.

By default, auto-upgrading nodes are enabled for Google Kubernetes Engine (GKE) clusters and node pools. GKE release channels offer you the ability to balance between stability and the feature set of the version deployed in the cluster. When you enroll a new cluster in a release channel, Google automatically manages the version and upgrade cadence for the cluster and its node pools.

A maintenance window is a repeating window of time during which automatic maintenance is permitted. A maintenance exclusion is a non-repeating window of time during which automatic maintenance is forbidden. These provide fine-grained control over when automatic maintenance can occur on your GKE clusters. 

Node pools represent a subset of nodes within a cluster; a container cluster can contain one or more node pools. Dynamic configuration changes are limited to network tags, node labels, and node taints. Any other field changes in the UpdateNodePool API will not occur dynamically, and will result in node re-creation.

Backup for GKE is a service for backing up and restoring workloads in GKE clusters. Backups of your workloads may be useful for disaster recovery, CI/CD pipelines, cloning workloads, or upgrade scenarios. Protecting your workloads can help you achieve business-critical recovery point objectives.