What it takes to run Stateful Workloads on Kubernetes: Thinking Beyond Just Storage

In the past few years, we have seen the emergence of close to 30 different CNCF certified vendors providing storage for stateful applications running on Kubernetes. With such broad vendor support, one would expect to see several organizations successfully running the most commonly used stateful workloads such as Splunk, ElasticSearch, Postgres, Cloudera, MongoDB, Oracle, etc on Kubernetes. But beyond some simple lab deployments, we rarely see production deployments of these workloads. Why?