Long-term SLOs for reclaimed cloud computing resources
Venue
ACM Symposium on Cloud Computing (SoCC), ACM, Seattle, WA, USA (2014), 20:1-20:13
Publication Year
2014
Authors
Marcus Carvalho, Walfredo Cirne, Franciso Brasileiro, John Wilkes
BibTeX
Abstract
The elasticity promised by cloud computing does not come for free. Providers need
to reserve resources to allow users to scale on demand, and cope with workload
variations, which results in low utilization. The current response to this low
utilization is to re-sell unused resources with no Service Level Objectives (SLOs)
for availability. In this paper, we show how to make some of these reclaimable
resources more valuable by providing strong, long-term availability SLOs for them.
These SLOs are based on forecasts of how many resources will remain unused during
multi-month periods, so users can do capacity planning for their long-running
services. By using confidence levels for the predictions, we give service providers
control over the risk of violating the availability SLOs, and allow them trade
increased risk for more resources to make available. We evaluated our approach
using 45 months of workload data from 6 production clusters at Google, and show
that 6--17% of the resources can be re-offered with a long-term availability of
98.9% or better. A conservative analysis shows that doing so may increase the
profitability of selling reclaimed resources by 22--60%.
