SpotCheck

Abstract

Infrastructure-as-a-Service (IaaS) cloud platforms rent resources, in the form of virtual machines (VMs), under a variety of contract terms that offer different levels of risk and cost. For example, users may acquire VMs in the spot market that are often cheap but entail significant risk, since their price varies over time based on market supply and demand and they may terminate at any time if the price rises too high. Currently, users must manage all the risks associated with using spot servers. As a result, conventional wisdom holds that spot servers are only appropriate for delay-tolerant batch applications. In this paper, we propose a derivative cloud platform, called SpotCheck, that transparently manages the risks associated with using spot servers for users.SpotCheck provides the illusion of an IaaS platform that offers always-available VMs on demand for a cost near that of spot servers, and supports all types of applications, including interactive ones. SpotCheck's design combines the use of nested VMs with live bounded-time migration and novel server pool management policies to maximize availability, while balancing risk and cost. We implement SpotCheck on Amazon's EC2 and show that it i) provides nested VMs to users that are 99.9989% available, ii) achieves nearly 5× cost savings compared to using equivalent types of ondemand VMs, and iii) eliminates any risk of losing VM state.

A pilot trial of mobile, patient-performed teledermoscopy

“…The segmental analysis becomes relevant as some patients may request that only a specific lesion be checked, potentially overlooking a melanoma on another site. Indeed, a pharmacy group in Australia has announced a new health programme called 'spot check', 29 wherein family doctors provide a teledermoscopy diagnosis for one to three concerning lesions photographed at pharmacies. Patients who receive reassurance about submitted lesions may then not attend a doctor for a CSE.…”

Parasite cloud service providers: on-demand prices on top of spot prices

“…For example, suppose that we can keep the probability of unavailability in a minute to be at most 0.0011% (as in [7]). So εugoodbreakafter=0.000011.…”

“…Table 1 shows optimistic as well as pessimistic upper bounds for the SLA violation penalty with respect to the availability commitment stated in the SLA. It is assumed that the expected availability is 99.9989%, from the results of [7].…”

“…[7] develops a cloud platform named SpotCheck which provides IaaS on top of the spot instances of a native IaaS provider. The price of the provided service is near the spot price of the underlying CSP but its availability is about 99.9989%.…”

Bulk-bin-packing based migration management of reserved virtual machine requests for green cloud computing

“…Customers can book reserved VMs in advance if resource quantities are wellknown, otherwise on-demand instances at a premium cost. To improve profits, the CSP offers the unutilized resources in the running PMs as spot instances [22] and can be taken back at short notice if required. This paper proposes a split in the management of reserved and on-demand VM requests with different placement and migration controllers since their incoming and outgoing behaviour is different.…”