I would like to know whether we need kubernetes cluster as required by cloud2edge package as mentioned in the link (https://www.eclipse.org/ditto/2018-05-02-connecting-ditto-hono.html) even if both hono and ditto are running in the sandbox environment provided for evaluation purpose ?
When you use the sandboxes, you don't have the need for you own Kubernetes cluster, no.
However, using the sandboxes, you have some restrictions as you are not the "admin" of the 2 installations and therefore you e.g. can't create new tenants in Hono or create new connections in Ditto.