By default, the buildmaster sends a simple, non-blocking message to each slave every hour. These keepalives ensure that traffic is flowing over the underlying TCP connection, allowing the system's network stack to detect any problems before a build is started.
The interval can be modified by specifying the interval in seconds using the keepalive_interval parameter of BuildSlave:
c['slaves'] = [ BuildSlave('bot-linux', 'linuxpasswd',
keepalive_interval=3600),
]
The interval can be set to None to disable this functionality
altogether.