Install and Start TeamCity Agents
A TeamCity build agent is a piece of software which listens for the commands from the TeamCity server and starts the actual build processes. A production TeamCity setup requires installing additional build agents on dedicated machines. Before that, make sure to read notes on agent-server communication, system requirements, conflicting software, and security.
If you install TeamCity bundled with a Tomcat servlet container, or use the TeamCity installer for Windows, both the server and one build agent are installed on the same machine. This is not a recommended setup for production purposes because of security concerns. Moreover, the build procedure can slow down the responsiveness of the web UI and overall TeamCity server functioning.
Agent-Server Data Transfer
A TeamCity agent connects to the TeamCity server via the URL configured as the
serverUrl agent property. This is called unidirectional agent-to-server connection.
Agents use unidirectional agent-to-server connection via the polling protocol: an agent establishes an HTTP(S) connection to the TeamCity Server, and polls the server periodically for server commands.