Automated Scaling Listener
The automated scaling listener mechanism is a service agent that monitors and keeps track of communication between cloud service consumers and cloud services for load balancing purposes. This automated scaling listener resides within the cloud, typically near the firewall, from where it automatically tracks load status information.
Automated scaling listeners can provide different types of responses to load fluctuation conditions, for example:
- The automated scaling listener can automatically scale out or scale in IT resources based on parameters previously defined by the cloud consumer (commonly referred to as auto-scaling).
- The automated scaling listener can automatically notify the cloud consumer when loads exceed current thresholds or are falling below allocated resources (Figure 1). This way, the cloud consumer can choose to adjust its current IT resource allocation.
Note that different cloud provider vendors have different names for service agents acting as automated scaling listeners.
Figure 1 - Three cloud service consumers attempt to access one cloud service simultaneously (1). The automated scaling listener scales out and initiates the creation of three redundant instances of the service (2). A fourth cloud service consumer attempts to use the cloud service (3). Programmed to allow up to only three instances of the cloud service, the automated scaling listener rejects the fourth attempt and notifies the cloud service consumer that the requested load limit has been exceeded (4). The cloud consumer accesses the remote administration environment to adjust the provisioning setup and increase the redundant instance limit (5).