On-Demand Resource Provisioning for Online Games

Online entertainment including gaming is a strongly growing sector worldwide. Massively Multiplayer Online Games (MMOG) grew from 10 thousand subscribers in 1997 to 6.7 million in 2003 and the rate is accelerating estimated to 60 million people by 2011. Today`s MMOGs operate as client-server architectures, with server Hosters providing a large static infrastructure with hundreds to thousands of computers for each game in order to deliver the required Quality of Service (QoS) to all the players. Since the demand of a MMOG is highly dynamic, a large portion of the resources is unused most of the time, even for large providers that operate several game titles in parallel. This inefficient resource utilisation has negative economic impacts by preventing any but the largest hosting centres from joining the market and dramatically increases prices. Today, a new research direction coined by the term Cloud computing proposes a cheaper hosting alternative by leasing virtualised resources large specialised data centres only when and for how long they are needed, instead of buying expensive own hardware with costly maintenance and fast deprecation. Despite the existence of many vendors that aggregate a potentially unbounded number of resources, Cloud computing remains a domain dominated by Web hosting or data-intensive applications, and whose suitability for computationally-intensive applications remains largely unexplored. In this project we propose to conduct basic research that investigates new generic Cloud computing techniques to support QoS-enabled resource provisioning for computationally-intensive real-time applications by investigating: Performance models for virtualised Cloud resources, including characterisation of the Cloud virtualisation and software deployment overheads; Proactive dynamic scheduling strategies based on QoS negotiation, monitoring, and enforcement techniques; SLA provisioning models based on an optimised the balance between risks, rewards, and penalties; Resource provisioning methods based on time/space/cost renting policies, including a comparative analysis between Cloud resource renting and conventional parallel/Grid resource operation. Our ultimate goal is to apply and validate our generic methods to MMOGs, as a novel class of socially important applications with severe real-time computational requirements to achieve three innovative objectives: Improved scalability of a game session hosted on a distributed Cloud infrastructure to a larger number of online users than the current state-of-the-art (i.e. 64 - 128 for FPS action games); Cheaper on-demand provisioning of Cloud resources to game sessions based on exhibited load; QoS enforcement with seamless load balancing and transparent migration of players from overloaded servers to underutilised ones within and across different Cloud provider resources.

Successful Massively Multiplayer Online Games (MMOGs) have today millions of registered users and hundreds of thousands of active concurrent players. To be able to guarantee a good quality of service (QoS) to a highly variable number of concurrent users, game operators statically overprovision a large infrastructure capable of sustaining the game peak load, even though a large portion of the resources is unused most of the time. This inefficient utilisation of own resources makes the market accessible only to large companies which generates monopolies and increases prices.To address this problem, we proposed in this project a new ecosystem for hosting and provisioning of MMOGs which effectively splits the traditional monolithic MMOG companies into three lightweight and focused service providers: game providers, game operators, and resource providers. Their interaction is regulated through comprehensive Service Level Agreements (SLA) that establish the price, terms of operation, and compensation for QoS violations. In our model, resource providers are represented by Infrastructure-as-a-Service Cloud data centres that lease computing resources to their customers (represented by game operators) based on hourly prices. Game operators, on the other hand, efficiently provision resources for MMOGs from multiple Cloud providers based on dynamic MMOG load forecasts, and ensure proper game operation that maintains the required QoS to all clients under varying resource availability. Game providers manage multiple distributed MMOGs for which they lease services under strict operational SLAs from game operators to satisfy all client requests. These three self-standing, smaller, more agile service providers enable access to the MMOG market for the small and medium enterprises, and to the current commercial Cloud providers with nearly zero initial investment.We demonstrated through simulations using trace data collected from RuneScape, one of the largest MMOGs on the market, that our new Cloud-based hosting model achieves a reduction in resource waste from 250% in case of own resource provisioning to around 25% in case of on-demand resource leasing. Our new ecosystem can operate state-of-the-art MMOGs with an average monthly gross profit of nearly $6 million excluding game purchase prices, overheads and taxation, while providing high QoS to all clients. Furthermore, our approach is capable of operating next generation very highly interactive MMOGs with a small increase of only 5.8% in the subscription price. We also showed that considering compensations for QoS faults in the offer selection process can lead up to 1116% gain in the game providers' income.