Comment 7 for bug 1316475

The culprit here is that there is no timeout on the serial console read/write.

From cloudinit/cs_utils.py
 73 def __init__(self, request):
 74 self.request = request
 75 self.raw_result = self._execute()
 76 self.result = self._marshal(self.raw_result)
 77
 78 def _execute(self):
 79 connection = serial.Serial(SERIAL_PORT)
 80 connection.write(self.request)
 81 return connection.readline().strip('\x04\n')

Further, since we are blocking on the serial port, I have to question whether or not this should be a default enabled source. The other serial terminal DS is SmartOS, which is disabled by default. There are a lot of good reasons why people attach serial consoles, but assuming that it safe for cloud-init to read/write to a serial console seems like a great way to break infrastructure or control planes.

IMHO, I think that the fix should be twofold 1) disable this ds by default; 2) enforce a reasonable time out. I've attached a rough patch of what I am thinking here.

We should get CloudSigma to clarify what the timeout should be before we enforce the timeout.

That said, I think that an SRU that disables the DS is warranted.