Determines how long slaves can remain idle before being stopped or terminated (see the Stop/Disconnect on Idle Timeout setting). Also determines how frequently nodes are checked for stopping/terminating.

Times are expressed in minutes, and a value of 0 (or an empty string) indicates that idle slaves should never be stopped/terminated. Positive values are simple time-outs after that many idle minutes. Negative values cause the node to time out when found idle within the specified number of minutes from the end of an hourly EC2 billing period.

As an example, let's say a node was started at 11:00.

If it has an idle timeout of 5 it will be checked every 5 minutes starting at 11:05. If it's checked at 11:30 and has been idle since 11:26 (for 4 minutes), it will be stopped or terminated.

If it has an idle timeout of -5 it will first be checked at 11:55, and then continuously until 12:00. If it becomes idle during that time it will be stopped or terminated.