The elasticity of reactive systems

Elasticity is about the capability of responsiveness under a load. Systems can be used by many users suddenly, or a lot of data can be pumped by hundreds of thousands of sensors and devices into the system. To tackle this unplanned rush of users and data, systems have to automatically scale up or out by adding additional resources (bare metal servers, virtual machines, and containers). The cloud environments are innately enabled to be auto-scaling based on varying resource needs. This capability makes systems to use their expensive resources in an optimized manner. When resource utilization goes up, the capital and operational costs of systems comes down sharply.

Systems need to be adaptive enough to perform auto-scaling, replication of state, and behavior, load-balancing, fail-over, and upgrades without any manual intervention, instruction, and interpretation. In short, designing, developing, and deploying reactive systems through messaging is the need of the hour.