DBMS in a container/cluster vs data corruption

I am fairly new to db administrations as well as containerization/kubernetes concepts. I see every here and then containerized/clustering solutions for i.e. running PostgreSQL (i.e. [here](https://www.enterprisedb.com/docs/kubernetes/cloud_native_postgresql/interactive_demo) . This conflicts with info I get during my training where it is said that _"**databases can not run into ephemeral enironments like containers to avoid data corruption**"_ on container-failure. The same logic should generally apply to Kubernetes clusters alike. Can anybody clarify how these two points of views play together?