  Transient computing has become popular in public cloud environments for
running delay-insensitive batch and data processing applications at low cost.
Since transient cloud servers can be revoked at any time by the cloud provider,
they are considered unsuitable for running interactive application such as web
services. In this paper, we present VM deflation as an alternative mechanism to
server preemption for reclaiming resources from transient cloud servers under
resource pressure. Using real traces from top-tier cloud providers, we show the
feasibility of using VM deflation as a resource reclamation mechanism for
interactive applications in public clouds. We show how current hypervisor
mechanisms can be used to implement VM deflation and present cluster deflation
policies for resource management of transient and on-demand cloud VMs.
Experimental evaluation of our deflation system on a Linux cluster shows that
microservice-based applications can be deflated by up to 50\% with negligible
performance overhead. Our cluster-level deflation policies allow overcommitment
levels as high as 50\%, with less than a 1\% decrease in application
throughput, and can enable cloud platforms to increase revenue by 30\%.
