Heartbeat messages are periodic signals sent between components of a distributed system to indicate that they are still alive and functioning properly. These messages serve as a form of health check, allowing each component to monitor the status of its peers and detect failures or network issues. The term “heartbeat” comes from the analogy of the periodic pulsing of a heart, indicating that it is still beating and functioning. Similarly, in a distributed system, heartbeat messages are regularly sent between components to ensure that they are operational.