The open, dynamic and ever-changing natures of Internet require the just-in-time scalability of middleware for Internetware. As the middleware for Internetware becomes much more powerful and complicated than ever, it is challenging to auto-scale middleware dynamically and efficiently under the Internetware environment. In this paper, a profile-based approach is proposed to automate the dynamic scaling of Internetware middleware. Profiles formalize (a) states that are keys to consistent middleware being scaled;(b) reflected information required to trigger and fulfill dynamic scaling; and (c) the best-practice of scaling domain-specific middleware. The auto-scaling tool based on this approach is capable of provisioning a scalable middleware and scale it dynamically according to the needs of Internetware. The provisioning and dynamic scaling of a scalable Mongrel cluster exemplifies the feasibility and efficiency of this approach.