Velero
Backs up a Kubernetes cluster: both the objects in the API server and the contents of the volumes. Used as often to move workloads between clusters as for disaster recovery.
The tool was called Ark when Heptio released it in 2017. A backup is a query against the API server — filtered by namespace, label or resource type — whose result is serialised into object storage, plus snapshots of persistent volumes via CSI or file-level copies with Kopia. A restore can remap namespaces, which is what makes cluster migration practical. Schedules are expressed as custom resources with a retention period. The important caveat: an etcd backup is not the same thing, and neither helps if nobody has ever tried a restore. Exercise it into an empty cluster periodically, or you don't know whether it works.