The ifmgrd service provides a mechanism for applying interface configuration at plug time. It handles interface config events for registered interfaces. For this to work properly configd must be told not to run the commit actions by using the 'configd:defer-child-actions' YANG statement in the desired interface's data-model. These deferred actions will then be run asynchronously by ifmgrd either immediately if the interface exists or at plug time when the interface comes into existance. The ifmgrd service also emulates the configd commit time interface so the environment the deferred action scripts execute in look very similar to the environment configd would run them in.
Each managed interface is controlled by a state-machine that tracks the current state and transitions based on the received events. Events are generated with the ifmgrctl utility.
NOTE: ifmgrd is meant to be a temporary solution providing hotplug configuration services using legacy commit scripts. A more permanent solution would not rely on the commit library to apply the configuration but would have a more direct mechanism, and an intermediate configuration file format. This services state-machine, would however provide an appropriate basis for such a daemon.
| state | event | action | new state |
|---|---|---|---|
| unplugged | apply | stage new config | unplugged |
| unplugged | reset | delete staged config | unplugged |
| unplugged | plug | apply staged config | applying |
| unplugged | kill | shutdown state-machine | shutdown |
| applying | apply | stage new config | applying |
| applying | reset | stage empty config | applying |
| applying | unplug | remove running config | unplugged |
| applying | shutdown | shutdown state-machine | shutdown |
| applying | done | set running = applied config | if candidate != running applying else plugged |
| plugged | apply | stage new config; apply staged config | applying |
| plugged | reset | stage empty config; apply staged config | applying |
| plugged | unplug | remove running config | unplugged |
| plugged | kill | shutdown state-machine | shutdown |
Usage: ifmgrctl <action> <args>
Available actions:
apply apply latest config to managed interfaces
plug send plug event for device
register register a new device to be managed
unplug send unplug event for device
unregister stop managing a device
Apply downloads the latest configuration from configd and then sends it to ifmgrd.
Plug signals that an interface was added to the system, if the interface is not currently managed by ifmgrd the plug event is ignored. This will apply the cached candidate configuration to the interface.
Unplug signals that an interface was removed, this causes the running configuration to be reset to an empty state. The candidate configuration will remain and be applied on the next plug event.
Register signals to start listening for events on a given interface.
Unregister stops the state-machine for an interface and removes the state from the manager. All previously applied configuration remains active.