Wake-On-Lan is a standard that allows a computer to be powered on by a network message. This is widely available and doesn’t require any fancy hardware to work with [1].
The Wake-On-Lan driver is a testing driver not meant for production. And useful for users that wants to try Ironic with real bare metal instead of virtual machines.
It’s important to note that Wake-On-Lan is only capable of powering on the machine. When power off is called the driver won’t take any action and will just log a message, the power off require manual intervention to be performed.
Also, since Wake-On-Lan does not offer any means to determine the current power state of the machine, the driver relies on the power state set in the Ironic database. Any calls to the API to get the power state of the node will return the value from the Ironic’s database.
The pxe_wol driver uses the Wake-On-Lan technology to control the power state, PXE/iPXE technology for booting and the iSCSI methodology for deploying the node.
Add pxe_wol to the list of enabled_drivers in /etc/ironic/ironic.conf. For example:
[DEFAULT]
...
enabled_drivers = pxe_ipmitool,pxe_wol
Restart the Ironic conductor service:
service ironic-conductor restart
Nodes configured for Wake-On-Lan driver should have the driver property set to pxe_wol.
The node should have at least one port registered with it because the Wake-On-Lan driver will use the MAC address of the ports to create the magic packet [2].
The following configuration values are optional and can be added to the node’s driver_info as needed to match the network configuration:
Note
Say the ironic-conductor is connected to more than one network and the node you are trying to wake up is in the 192.0.2.0/24 range. The wol_host configuration should be set to 192.0.2.255 (the broadcast IP) so the packets will get routed correctly.
The following sequence of commands can be used to enroll a node with the Wake-On-Lan driver.
Create node:
ironic node-create -d pxe_wol [-i wol_host=<broadcast ip> [ -i
wol_port=<destination port>]]
The above command ironic node-create will return UUID of the node, which is the value of $NODE in the following command.
Associate port with the node created:
ironic port-create -n $NODE -a <MAC address>
The agent_wol driver uses the Wake-On-Lan technology to control the power state, PXE/iPXE technology for booting and the Ironic Python Agent for deploying the node.
Configuration steps are the same as for pxe_wol driver, replace “pxe_wol” with “agent_wol”.
| [1] | Wake-On-Lan - https://en.wikipedia.org/wiki/Wake-on-LAN |
| [2] | Magic packet - https://en.wikipedia.org/wiki/Wake-on-LAN#Sending_the_magic_packet |