What is a self-adaptive system?

A self-adaptive system is a system that adapts to changing conditions. That was evident, wasn't it? In practical terms, when operating a cluster and deploying services, that means that a system should adapt when a new service is deployed, or an existing one is updated. When conditions in a cluster change, the whole system should change by adapting to those conditions. If a new service is deployed, the monitoring solution should get the information about that service and change its configuration. A logging system should start processing the logs of that service and parse it correctly. The number of nodes in the cluster should adjust. And so on and so forth. The most important requirement for a system to self-adapt is to create it in such a way that human intervention is not needed. Otherwise, we can just as well change the name from self-adaptive to John-adapts-it system.