For multi tenancy support, I would like to create like a datastore concept limiting the storage per tenant across all namespaces in the tenant. Kubernetes website [1] says "given namespace", but I want to be able to set resource quota based on storage class but not limited to "per namespace". How can I do that ?
Not directly. The quota system is per namespace only. But of course you can make a validating webhook yourself which implements whatever logic you want.