Agents

Agents are specialized Services that run a single Process on each Instance.

Defining an Agent

You can define any Service as an Agent by setting its agent attribute to true

services:
  telemetry:
    agent: true

Communicating with an Agent

Often it is useful for other Processes to communicate with an Agent running on its Instance.

You can declare ports that will be available to communicate with an Agent using the ports attribute:

services:
  telemetry:
    agent: true
    ports:
      - 8125/udp
      - 8126

Agents will listen on the IP address of the underlying Instance. This means that you cannot deploy two Agents on the same Rack that listen on the same port.

Each Process will have the IP address of its Instance available in the INSTANCE_IP environment variable.

In the example above, any Process on the same Rack can communicate with the telemetry Agent running on its Instance using the following endpoints:

• udp://$INSTANCE_IP:8125
• tcp://$INSTANCE_IP:8126

A process can only communicate with the agent running on the same node. Ensure the INSTANCE_IP corresponds to the node that the process is running on.