I @Med_amine_Boujelbene!
Even though it’s possible, I’d not recommend using MySQL inside your K8s cluster (and actually, none of the workloads that use persistent volumes, namely MongoDB, Redis, OpenSearch). You can do for testing, but in production environments you will sooner or later have big problems. Instead, create your databases separately or -better- use a DB-as-a-service from your cloud provider and connect them to your cluster.
Hope it helps!
Andrés.