A cloudlet is a small-scale data centre located at the edge of the Internet to provide computing resources to mobile applications with lower latency. It is a newer architectural element of cloud computing infrastructure of a 3-tier hierarchy: mobile device or IoT hardware, cloudlet, cloud. The cloudlet concept is also known as mobile micro-cloud. The term was first suggested by Satyanarayanan as “a trusted, resource-rich computer or cluster of computers that is well-connected to the Internet and is available for use by nearby mobile devices.”
Many of the smartphone applications divide the application into a front-end client and a back-end server. The front-end mobile application depends on the back-end servers for reasons like speeding up processing. The back-end server of today typically hosted at the cloud datacenter offering benefits such as scalability and elasticity. End-to-end communication involves many network hops resulting in high latencies. Some of the emerging mobile applications require to offload infrastructure geographically close to the mobile device. This method achieves a low response time. The individual elements of this kind of infrastructure are known as cloudlets. A cloudlet has four key attributes:
- only soft state
- powerful, well-connected and safe
- close at hand
- builds on standard cloud technology
The cloudlets aim to support the mobile and IoT applications which are resource-intensive and interactive. Augmented reality applications with head-tracking systems require very low latency. Cloud gaming systems which need rendering on the remote server also require low latencies. Wearable cognitive assistance systems (like Google Glass) require low-latency cloud-based processing for complex tasks. Apple Siri with compute-intensive speech recognition in the cloud is a classic example of use-case.
Cloudlet requires the additional deployment of hardware/software. OpenStack++ extends OpenStack to leverage its open ecosystem with a set of cloudlet-specific API as OpenStack extensions. The biggest challenge is ensuring automated provisioning of the cloudlet applications.