What is Elasticity (in contrast to Scalability)?

Elasticity, in the context of cloud computing, refers to the ability of a system to automatically adjust its resource capacity up or down in response to changing demands, without manual intervention. This characteristic is crucial for handling unpredictable, dynamic workloads where the amount of resources needed can fluctuate significantly and suddenly[1][2][3][4][5].

In contrast, scalability is about the capacity of a system to handle increased workloads by adding resources, either vertically (scaling up) by enhancing the capabilities of existing resources, or horizontally (scaling out) by adding more instances of resources. Scalability is typically planned and involves manual configuration to accommodate expected increases in demand[1][2][3][4][5].

While both elasticity and scalability deal with changing demands, the key difference lies in how and when these adjustments are made. Elasticity is reactive and automat...