Definition
A Pilot Light is a cloud disaster recovery strategy where a minimal version of a critical system is always running in the cloud. This core infrastructure is kept warm and ready to scale up rapidly in the event of a disaster. It allows for quick recovery by having essential components pre-provisioned and configured. For example, a Pilot Light setup might include a database server and a small web server instance, with the full application stack ready to be deployed on demand. This differs from a warm standby, which has more components running and ready, or a hot standby, which is fully replicated and active. This concept is frequently tested on cloud security certifications like CCSP and AWS exams.