The article is the final part in a series about deploying the ELK stack on Kubernetes using the ECK operator, focusing on managing Elasticsearch's persistent data storage through Persistent Volumes (PVs). It highlights the necessity of PVs for stateful applications like Elasticsearch, explaining how to create, allocate, and manage these volumes within a Kubernetes environment. The text details the process of setting up a multi-node Elasticsearch cluster, utilizing PVs to enhance performance and resiliency through a hot-warm architecture, which allocates frequently accessed data to faster servers, thereby optimizing costs. Additionally, it covers managing cluster scaling and upgrading Elasticsearch versions via Kubernetes YAML configurations, emphasizing the importance of cautious upgrade procedures in live production environments to maintain data integrity and service continuity. The article concludes by encouraging readers to explore further resources on running ELK on Kubernetes and related topics.