Heartbeat Mechanism

The heartbeat mechanism is the basis for service registration in service governance. Below is the class diagram of the heartbeat mechanism:

As shown above, there are both client heartbeat mechanism and server heartbeat mechnism.

• The client heartbeat mechanism generates the contents of heartbeat messages and send the messages to the server every 15 minutes by default via Http.

  Message contents:

  1. Modules and Http servers started by the MSCP node;
  2. Context data: OS information, JDK information and disk use;
  3. Context performance data: CPU, memory, conncetion count, port traffic and disk IO. Client life cycle: Alive (1*TTL, green) —> Dying (2*TTL, red) —> Dead (5*TTL, grey)—> Disappear (10*TTL)

• The server heartbeat mechanism stores the contents of the heartbeat messages and handles the cascading with the multi-level service registration center. Storage: CacheManager hash structure:

  node.info:
  key: NodeInfo.id,
  value: NodeInfo JSON
  

  Cascading: multi-level service registration center. Some business scenarios have low tolerance with the update latency of the service registration information, which requires the computational node of the heartbeat cascading to be a service registration center.