Nodes in "Idle Host" mode

A node can be configured to run only when its host is considered idle, that is, when no keyboard or mouse activity has occurred for a specified time.

The idleness detection and behavior are specified with the following node configuration properties:

# enable/disable idle mode, defaults to false (disabled)
jppf.idle.mode.enabled = true

# Time of keyboard and mouse inactivity after which the system is considered
# idle, in milliseconds. Defaults to 300000 (5 minutes)
jppf.idle.timeout = 6000

# Interval between 2 successive calls to the native APIs to determine whether
# the system idle state has changed. Defaults to 1000 ms
jppf.idle.poll.interval = 1000

# Whether to shutdown the node immediately when a mouse/keyboard activity is detected,
# or wait until the node is no longer executing tasks. Default value is true (immediate
# shutdown)
jppf.idle.interruptIfRunning = true

With the above settings, the node will be started whenever there has been no user input for at least 6 seconds, the check for idleness will occur every second, and the node will stop immediately whenever the user resumes activity.

When the node is set to stop immediately upon user activity resumption, this will trigger the normal server behavior, which is to resubmit the tasks based on the resubmission settings at the job or task level.

Please note that the following node deployments are incompatible with the idle mode:

• local nodes, running in the same JVM as a driver
• slave nodes, when using node provisioning. However, the master node supports the idle mode

The idleness detection feature relies on a JNI bridge provided by the JNA libraries, provided in the node distribution. Consequently, it is not guaranteed to work with all platforms. It should work will all Windows versions from Windows Vista upwards, all Linux/BSD/Unix distributions which have the XScreenSaver library installed, and Mac OS/X. In particular, this feature may not be supported with some Unix-based OSes.