service interruption in order to handle the workload variation” COUTINHO et al. Elasticity in cloud computing: a survey. In: Ann. Telecommun. 2014. Demand Capacity Time Resources
to adapt to workload changes by provisioning and de-provisioning resources in an autonomic manner, such that at each point in time the available resources match the current demand as closely as possible. 4 Herbst et al. Elasticity in Cloud Computing: What It Is, and What It Is Not. In: ICAC. 2013.
to unpredicted demand. • Ability to free resources when they are not needed allowing to reduce costs. Provider • Allows VM consolidation and reduced server usage. • Keep SLAs/cluster occupancy ratio with the minimum resources possible. • Increase profit. 6 Beernaert et al. Automatic Elasticity in OpenStack. In: SDMCMM. 2013.
Allocation Capacity Available Supply, Capacity, System Capacity Meter (SCM), System Effective Capacity Meter (SEC) Cost Cost/ Performance rate, Cost Bandwidth, Migration Cost, Total Cost of Deployment QoS % Violations, SLA, System Performance Meter (SPM) Resource Utilization % Utilization, Cloud Stress, Computing Resource Utilization Meter (CRUM) Scalability Effective Scalable Range (ESR), Effective System Scalability (ESS), Scale-up Time Boot, Creation, Deletion, Resource Deallocation, Startup COUTINHO et al. Elasticity in cloud computing: a survey. In: Ann. Telecommun. 2014.
Not strictly at VM-level Real-time • Adaptive to changes in load, infrastructure and objective function • Prediction Elasticity to guarantee QoS • SLA to cloud storage 28