acrnctl and acrnd


The acrnctl tool helps users create, delete, launch, and stop a User OS (UOS). The tool runs under the Service OS, and UOSs should be based on acrn-dm. The daemon for acrn-manager is acrnd.


You can see the available acrnctl commands by running:

# acrnctl help
  stop [--force/-f]
Use acrnctl [cmd] help for details


You must run acrnctl with root privileges.

Here are some usage examples:

Add a VM

The add command lets you add a VM by specifying a script that will launch a UOS, for example

# acrnctl add -U 1
vm1-14:59:30 added

If a -C option is also specified, the VM is launched in a runC container:

# acrnctl add -C


You can download an example script that supports the -C (run_container function) option. You may refer to Enable QoS based on runC container for more details about this option.

Note that the launch script must only launch one UOS instance. The VM name is important. acrnctl searches VMs by their names so duplicate VM names are not allowed. If the launch script changes the VM name at launch time, acrnctl will not recognize it.

Delete VMs

Use the delete command with a VM name to delete that VM:

# acrnctl del vm1-14:59:30

List VMs

Use the list command to display VMs and their state:

# acrnctl list
vm1-14:59:30            untracked
vm-yocto                stopped
vm-android              stopped

Start VM

If a VM is in a stopped state, you can start it with the start command:

# acrnctl start vm-yocto

Stop VM

Use the stop command to stop one or more running VM:

# acrnctl stop vm-yocto vm1-14:59:30 vm-android

Use the optional -f or --force argument to force the stop operation. This will trigger an immediate shutdown of the User VM by the ACRN Device Model and can be useful when the User VM is in a bad state and not shutting down gracefully by itself.

# acrnctl stop -f vm-yocto


Use the blkrescan command to trigger a rescan of virtio-blk device by guest VM, in order to revalidate and update the backend file.

# acrnctl blkrescan vmname slot,newfilepath
vmname:     Name of VM with dummy backend file attached to virtio-blk device.
slot:       Slot number of the virtio-blk device.
newfilepath: File path for the backend of virtio-blk device.

acrnctl blkrescan vm1 6,actual_file.img


blkrescan is only supported when VM is launched with empty backend file (using nodisk) for virtio-blk device. Replacing a valid backend file is not supported and will result in error.


The acrnd daemon process provides a way for launching or resuming a UOS should the UOS shut down, either planned or unexpected. A UOS can ask acrnd to set up a timer to make sure the UOS is running, even if the SOS is suspended or stopped.


You can see the available acrnd commands by running:

$ acrnd -h
acrnd - Daemon for ACRN VM Management
[Usage] acrnd [-t] [-d delay] [-h]
-t: print messages to stdout
-d: delay the autostarting of VMs, <0-60> in second (not available in the
    ``RELEASE=1`` build)
-h: print this message

Normally, acrnd runs silently (messages are directed to /dev/null). Use the -t option to direct messages to stdout, useful for debugging.

The acrnd daemon stores pending UOS work to /usr/share/acrn/conf/timer_list and sets an RTC timer to wake up the SOS or bring the SOS back up again. When acrnd daemon is restarted, it restores the previously saved timer list and launches the UOSs at the right time.

A systemd service file (acrnd.service) is installed by default that will start the acrnd daemon when the Service OS comes up. You can restart/stop acrnd service using systemctl


You must run acrnd with root privileges.

Build and Install

Source code for both acrnctl and acrnd is in the tools/acrn-manager folder. Change to that folder and run:

# make
# make install