I have problems in deploying a simple postgres container on minikube. It doesn't create "postgres" database when a persistent volume is mounted:

kubectl exec -it POSTGRES_POD -- sh

/ $ su postgres
/ $ psql
psql: FATAL:  database "postgres" does not exist

Here is my postgres deployment:

resource "kubernetes_deployment" "backend_postgres" {
  metadata {
    ...
  }

  spec {
    replicas = 1

    ...

    template {
      metadata {
        ...
      }

      spec {
        volume {
          name = "data"

          persistent_volume_claim {
            claim_name = kubernetes_persistent_volume_claim.data.metadata[0].name
          }
        }

        container {
          name  = "postgres"
          image = "postgres:10-alpine"

          port {
            container_port = 5432
          }

          env {
            name = "POSTGRES_PASSWORD"

            value_from {
              secret_key_ref {
                name = kubernetes_secret.postgres_password.metadata[0].name
                key  = "password"
              }
            }
          }
	
          volume_mount {
            name       = "data"
            mount_path = "/var/lib/postgresql/data"
            sub_path   = "postgres"
          }

        }
      }
    }
  }
}

The persistent volume successfully gets mounted and postgres successfully writes to /var/lib/postgresql/data but as I mentioned earlier, it doesn't create "postgres" database.

But when I don't mount a persistent volume, everything works fine.

Here is my deployment without mounting any persistent volume:

resource "kubernetes_deployment" "backend_postgres" {
  metadata {
    ...
  }

  spec {
    replicas = 1

    ...

    template {
      metadata {
        ...
      }

      spec {

        container {
          name  = "postgres"
          image = "postgres:10-alpine"

          port {
            container_port = 5432
          }

          env {
            name = "POSTGRES_PASSWORD"

            value_from {
              secret_key_ref {
                name = kubernetes_secret.postgres_password.metadata[0].name
                key  = "password"
              }
            }
          }
	
        }
      }
    }
  }
}

I'm working on this strange scenario for days.

I'm runing the kubernetes cluster on minikube. Any kind of help or suggestion would be really appreciated.