System Definition .sdef

.sdef files can contain these sections:


An apps: section declares one or more apps to be deployed to the target system.


This looks for an app definition file called webserver.adef and includes it in the system.

The apps: section can override limits and other app settings.

Here's a code sample to deploy a web server limiting its share of the CPU under heavy load to 500 (see CPU Share):

cpuShare: 500

Any of the following subsections can be used in an .sdef apps: section, and will override the .adef setting for all processes in that app:

CPU Share
Fault Action
Max Core Dump File Bytes
Max File Bytes
Max File Descriptors
Max File System Bytes
Max Locked Memory Bytes
Max Memory Bytes
Max MQueue Bytes
Max Priority
Max Queued Signals
Max Threads
Max Secure Storage Bytes
Watchdog Action
Watchdog Timeout

Max Priority

Sets the maximum priority level for running the app.

Acts as a ceiling only. Lowers the priority level if an app would otherwise be allowed to use a higher priority. It won't raise the priority level for any processes in the app.

Here's a code sample where a process in the app's .adef is configured to start at high priority, and the .sdef section for that app has maxPriority set to medium so the process will start at medium priority.

maxPriority: high

Another process in the same .adef configured to start at low priority will still start at low priority.


Lists IPC bindings that connect apps’ external IPC interfaces. They're listed in the extern section of their .adef files. Each binding connects one client-side interface to one server-side interface.

Interfaces use the app name and the interface name, separated by a period (‘.’). The two bound-together interfaces are separated by an arrow ("->").

Here's a code sample:

// Connect the VAV controller to the thermostat
vavController.temp -> thermostat.temp
vavController.setpoint -> thermostat.setpoint
// Connect the VAV controller to the supply air duct temperature sensor
vavController.ductTemp -> ductTemperatureSensor.temp
// Hook up the VAV control outputs to the damper actuators.
vavController.supplyDamper -> supplyAirDamper.damper
vavController.returnDamper -> returnAirDamper.damper
// Use a network proxy to request duct temperature changes from the Air Handling Unit.
vavController.airHandler -> airHandlerProxy.airHandler

For security reasons, binding between apps is never performed unless explicitly specified in the .sdef or .adef files.

Beware that if an app's client-side extern interface instance is left unbound, the process or processes that require that interface may not be able to run.

Copyright (C) Sierra Wireless Inc. Use of this work is subject to license.