Configuration of an APC UPS under Proxmox

Veröffentlicht von brun am

German Version

This is how to configure an APC-UPS under Proxmox:

These instructions are based on (German Text):

0. Connect the UPS to the server and switch it on

  1. The UPS can be controlled with the software apcupsd. Installation of this program:
apt-get install apcupsd

2. Editing the configuration file:

nano /etc/apcupsd/apcupsd.conf

The following options have to be changed in this file:

UPSNAME *Enter any device name*
DEVICE *leave empty, the program will automatically detect the UPS*


Furthermore, in this file the following settings can be changed:

    • The time between power failure and triggering of the „ON BATTERY“ event in seconds. The standard is 6 seconds so that an action is not triggered directly in the event of a brief failure.
    • This is the limit in percent of remaining battery capacity from when the server will shut down.
    • If the remaining runtime (calculated by the UPS) is less than this value (in minutes), the server is shut down.
    • The path to the log file
    • Time in seconds how often the server queries the UPS for its status

3. „Tell“ the program that it is completely configured:

    put in the file:
nano /etc/default/apcupsd


4. Start the program and check function:

apcupsd start
apcaccess status

5. Optional: Install web interface:

apt-get install apcupsd-cgi apache2
a2enmod cgi
systemctl restart apache2

Call up the status page at:


Configuration of Slaves

If other servers are connected to the UPS, they can be configured in such a way that the MASTER server (which is connected to the UPS via USB) causes the SLAVES to shut down in the event of a power failure.

These steps can also be carried out in Proxmox VMs, which cannot be shut down via the Proxmox interface.

See also:

  1. Changes in the configuration of the master:
nano /etc/apcupsd/hosts.conf

Enter the IP addresses of the servers that should work as SLAVES (these should be static IPs!):

# MONITOR <address> "<host description>"
MONITOR "Backup server"
MONITOR "Server 2"
systemctl restart apcupsd.service

2. Configuration of the SLAVE computers:

apt-get install apcupsd
nano /etc/apcupsd/apcupsd.conf

Change in this file:

# IP of the MASTER COMPUTER (in my case, The standard port for   apcupsd is 3551

The rest of the configuration is as above.

Optional: Web interface for quick access to the UPS status pages

I have created a small web interface that enables quick access to the status page and the Proxmox web interface.

To use it, just execute the following commands:

  1. Create a file „index.html“ in the web server directory
nano /var/www/html/index.html

2. Paste the following content into this file. The IP address to the Proxmox web interface has to be replaced by the IP address of the respective Proxmox server:

<h3>USV Status</h3> <br>
<a href="/cgi-bin/apcupsd/multimon.cgi">
apcupsd MultiMon
<a href="/cgi-bin/apcupsd/upsstats.cgi">
apcupsd Stats
<a href="/cgi-bin/apcupsd/upsfstats.cgi">
apcupsd fStats
<h3>Proxmox Webinterface</h3><br>
<a href="">   <!-- enter IP here! -->
Proxmox Webinterface

After that save the file. Now the interface can simply be called up under the server IP (http://–SERVER-IP–).

Kategorien: IT

5 Kommentare

Robert · 9. April 2023 um 22:28

Just what I was looking for! Thanks. I use your simple web interface now. Very useful.

Taomyn · 13. Dezember 2023 um 16:12

Is there an updated version for this because Proxmox no longer uses apache2 and instead has pveproxy to publish the web interface. Not sure that installing apache2 would be a good idea.

    brun · 19. Dezember 2023 um 21:13

    I have not yet looked into that since I am not running the latest version of proxmox on this system.

loulou91 · 20. Dezember 2023 um 17:16

Thank you for the tip!
And now, how could I simply check ups status and battery level in order tu request a stopall (containers and VMs)?
Any idea?

    brun · 22. Dezember 2023 um 18:50

    All this is done by the software apcupsd. If the UPS signals a power outtage, the proxmox-host is automatically shut down (after the configured interval). Before the proxmox-host shuts itself down, all VMs and containers are automatically shut down to.

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