Severity: a QoS-aware approach to cloud application elasticity

Abstract

While a multitude of cloud vendors exist today offering flexible application hosting services, the application adaptation capabilities provided in terms of autoscaling are rather limited. In most cases, a static adaptation action is used having a fixed scaling response. In the cases that a dynamic adaptation action is provided, this is based on a single scaling variable. We propose Severity, a novel algorithmic approach aiding the adaptation of cloud applications. Based on the input of the DevOps, our approach detects situations, calculates their Severity and proposes adaptations which can lead to better application performance. Severity can be calculated for any number of application QoS attributes and any type of such attributes, whether bounded or unbounded. Evaluation with four distinct workload types and a variety of monitoring attributes shows that QoS for particular application categories is improved. The feasibility of our approach is demonstrated with a prototype implementation of an application adaptation manager, for which the source code is provided.

Deployment Archetypes for Cloud Applications

“…Defining QoS or SLA for application stack would translate to the need of load balancing to support QoS and SLA targeted load balancing [88,121,135] as intent-based constraints that internally would need to be translated into signals such as target utilization, number of errors per type, adjustment to changing health of servers. Load balancing for long (streaming) and short (request/response) flows discussed in Reference [138] further influence the choice of deployment archetype for a specific type of traffic an application receives.…”

Correction to: Severity: a QoS-aware approach to cloud application elasticity

“…Following publication of the original article [1], the authors identified an error. This error has been corrected to express more accurately the work of Arkian et al [2].…”

“…This change should also make the last lines of the fourth paragraph of the Section on Rule-based and controltheoretic adaptation approaches more understandable. 1 The erroneous and corrected text are published in this correction article. The original article has been updated.…”