In this post, we take a look at how to enable Wake On Lan function on a server running XCP-ng.
Following implementation as detailed below, we note that this doesn’t seem to be powering up the server itself and wonder if it is more of a Wake On LAN to start and stop Virtual Machines withing XCP-ng ?? For this reason, it is suggested that you read this article instead… Though, the following is also useful for power cycling individual VMs.
With a server running 24/7 consuming substantial volume of electricity, solely to support my personal needs to store and access data, it has become too expensive and somewhat jeopardised my desire to run my own Cloud services and DIY DataCenter for my needs, despite having overcome all the technical challenges including setting up the hardware and software as well as acquiring Static IP addresses and implementing SSL certificates over the web services on top of numerous Open Source web seervices.. Now that it is ll working like clockwork, I have realized that it’s costing too much to keep my two servers powered up; These are a HP Z800 Workstation and a more modern version of this highly competent machine, the HP Z8 G4…
I wondered if it might be an idea to power down the servers, at least when I am going to bed and on days when I am not likely to need use of the Datacenter for any particular reason. To this end I have been aware of DRAC, iLO and WOL (Wake On LAN) technologies but, I had never looked into how to implement or even consider how useful it woulf be to turn on a server remotely…
Clearly, we can simply press the power button on the physical server and away we go but, my problem is that my servers are not ‘at home’. They’re running in a remote location and so, it is difficuly to power cycle these in person. It must be said that both physical servers can be shut down remotely using CLI. For example, we have a shutdown server button within XCP-ng Manager environment. On my HP Z800 Workstation, this does powe the system down since there is an ATX Power Supply in the box.
I have checked and despite not much detail, there is a Wake On LAN switch in the BIOS.. I hope I am not mistaken but this is the option in the BIOS-Security menu, listed as Network Service Boot. I have also dug up original HP Datasheets and identiified WOL in those, so I am sure it is possible. Of course, rnabling this in the BIOS is only one of several steps needed, we also need to configure the NIC (Network Interface Card) as well as setting up a Magic Packet and identify the servers IP address. We will look into each of these below…
IMPORTANT: This article was based on an article listed at the xen-rochestra-blog site and is intended for the XEN products, although xen is fundamentally based on the same origin as XCP-ng and so the same commands should be applicable. Just bear this in mind.
Also, note that in the original article, it states that once the steps have been implemented, with Xen Orchestra version 3.5.2 release onwards, we would see a START button in the HOST MENU if the host is HALTED. We simply click START to boot up…
Objective
To be able to power up our server remotely, simply by sending a Magic Packet to the NIC, when the system is in ‘standby mode’ or powered down.
Note taht what we mean by Standby or Powered down is simply this; The Server is powered down but its’ power cord is plugged into the power outlet in the wall.
ATX PSU. Our internal Power supply is equipped with a hard switch at the rear as part of the PSU, which disconnects mains power gettting into our PSU. Obviously, if this power switch is in the off position, then we have no power and no matter whether we press the on/off switch on the front of our machine, it would now start up.
This is one of the feartures of the ATX standard is that as long as the main power switch is on, then we can use a low power or logic-switch on the front of our machine to power up our system. In the same way as sending a logic-pulse using our logic-switch, the ATX motherboard can also accept a magic-packet arriving at the NIC and send a pulse to boot the system up. In essence this is the essence of Wake On LAN opertion…
0verview
We need to take several steps to achieve this.
step 1 – Hardware Configuration
In the absence of iLO(HP) or iDRAC(Dell), we can count on the WOL feature of our NIC – network card…
Step 2 – Configure the Operating System
XenServer (6) is based on CentOS. By default, when you shut down the host, it doesn’t activate the network card. In such a case, you can’t wake the server because the NIC is completely off. To remediate this we simply do…
Connect in to the host using favourite SSH tool (Putty)
ethtool -s eth0 wol gThis assumes that we’re a) running CentOS and b) our network is named eth0, so we ought to use this command as reference and make appropriate adjustments depending on our setup..
Othwerwise, that is all that is needed as far as setting up the OS, except…. If you want this to be permanently registered so that your system remembers it after a power cycle, then use the following command instead;
echo '/usr/sbin/ethtool -s eth0 wol g' >> /etc/rc.d/rc.localThis appends the command to your startup file so that it is non-volatile…
Step 3 – Configure XenServer
If using Xen Orchestra or XenCenter, we need to tell the XAPI how to wake the server, in the absence of WOL,iDRAC and iLO – or with a custom script…
Assuing we’re still SSH connected (else start up Putty again)..
xe host-set-power-on-mode uuid=<MyHost_UUID> power-on-mode=wake-on-lanIf we were using iDRAC or iLO, instead we’d simply replace wake-on-lan with DRAC or iLO respectively. . We’re ntot done yet!! We now need to give the XAPI the server’s IP and credentials of the Server Manager Tool, as follows;
# we can identify MyHost_UUID with this command
# xe host-list
#
# xe host-set-power-on-mode uuid=<MyHost_UUID> power-on-mode=DRAC power-on-config=xx.xx.xx.xx, user, password with xx.xx.xx.xx
#
# Example:
# First let's take alook at what's already inside our start-up script
[01:51 xcpng1 ~]# cat /etc/rc.d/rc.local
#!/bin/bash
# THIS FILE IS ADDED FOR COMPATIBILITY PURPOSES
#
# It is highly advisable to create own systemd services or udev rules
# to run scripts during boot instead of using this file.
#
# In contrast to previous versions due to parallel execution during boot
# this script will NOT be run after all other services.
#
# Please note that you must run 'chmod +x /etc/rc.d/rc.local' to ensure
# that this script will be executed during boot.
touch /var/lock/subsys/local
# NOT A LOT....
# Let's add a note to our file before the actual command....
[01:52 xcpng1 ~]# echo '# adding WOL command(ethtool -s eth0 wol g) to boot file 2024/11/10TT' >> /etc/rc.d/rc.local
#
## Great... Now add the command...
#
[01:52 xcpng1 ~]# echo '/usr/sbin/ethtool -s eth0 wol g' >> /etc/rc.d/rc.local
[01:52 xcpng1 ~]#
# done....
# now let's find out what our Host_UUID is...
[01:51 xcpng1 ~]#
[01:55 xcpng1 ~]# xe host-list
uuid ( RO) : 42b152a0-e538-4aa3-bb67-18a5f35bc3cb
name-label ( RW): xcpng1
name-description ( RW): Default install
# and finally, let's execute the command for WOL.
[02:05 xcpng1 ~]# xe host-set-power-on-mode uuid=42b152a0-e538-4aa3-bb67-18a5f35bc3cb power-on-mode=WOL power-on-config=62.31.247.106
[02:06 xcpng1 ~]#
# we'll need to experiment with powering down the system and seeing if we can wake it up again - to verify all is in order...We should be good to go!
step 4 – Triggering WOL
We have identified what seems like the ideal Windows application to initiate WOL. It is ideal because it has all the functions needed to assert WOL commands and is also an Open Source, free to use with option to donate and support the developers.
“WakeOnLAN is WOL / Shutdown software for Windows. A powerful WOL, ping, shutdown, GUI application. Do you need a robust, reliable solution for remote computer control and access? WakeOnLAN might be the program you want to use if you’re looking for something that is both powerful functionally and easy to use.”
https://wol.aquilatech.com/
Please check reference article if any form of validation is needed.