Controlling multiple kubernetes nodes from a single UPS server on a Synology NAS

Most UPS systems only have one USB port to control a single device in the event power outage and the battery running low. I have a couple of Synology NAS boxes with UPS and these can be used to shut down other devices safely.

Synology Setup

• Connect NAS to UPS via USB cable.
• Open up DSM and go to Control Panel > Hardware & Power > UPS (tab)
• Enable UPS Support and check “Enable network UPS server”
• Add the kubernete node IPs (works for other devices too) to “Permitted DiskStation Devices”
• Apply settings

Ubuntu

Synology is running a NUT Server (http://networkupstools.org) and in this part we have to install the Nut-client to monitor the NAS. The Linux set up is below, but the same basic steps apply for Mac/Windows. The NUT website has download/install instructions specific to Windows/Mac.

1. Install NUT

sudo apt-get install nut

2. Modify /etc/nut/nut.conf file to specify your computer/server as a client instead of server. Edit this specific line:

MODE=netclient

3. Add Synology address and credentials to /etc/nut/upsmon.conf

MONITOR ups@192.168.0.102 1 monuser secret slave

*Note: these credentials can be changed or you can add a user by SSHing into the NAS and modifying /etc/ups/upsd.users.

4. Lastly, start the nut-client service.

service nut-client restart