how to connect a 3-node cluster to a single ups?

FSNaval

Member
Jan 13, 2024
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good day to proxmox team and forum members,

i will upgrade my current (underpowered) ups to a more beefy one (most probably from Eaton or APC) and i dont know how to best connect my 3-node cluster to it.

The ups wil most probably has only one USB connection and i was thinking of connecting each node to the ups through a usb hub, the hib then to be connected to the usb itself.
Then, install nut on each node finally spin up a peaNUT server to monitor each nut client. This way, once a power failure is long enough to drain ups batteries, all of the nodes will receive a command to gracefully shutdow,

Do you think the above is workable/ferasible?

Do you have any preference over Eaton or APC?
 
good day to proxmox team and forum members,

i will upgrade my current (underpowered) ups to a more beefy one (most probably from Eaton or APC) and i dont know how to best connect my 3-node cluster to it.

The ups wil most probably has only one USB connection and i was thinking of connecting each node to the ups through a usb hub, the hib then to be connected to the usb itself.
Then, install nut on each node finally spin up a peaNUT server to monitor each nut client. This way, once a power failure is long enough to drain ups batteries, all of the nodes will receive a command to gracefully shutdow,

Do you think the above is workable/ferasible?

Do you have any preference over Eaton or APC?

Your approach is mostly workable, but USB hubs generally do not work well with UPS monitoring due to connection instability. Instead, consider these better solutions:

1️ Recommended Approach: Network-based UPS (SNMP or Network Card)

  • If your UPS supports SNMP or has a network management card, connect it via Ethernet.
  • Install NUT (Network UPS Tools) on one node as the NUT Server and configure the other nodes as NUT Clients.
  • This avoids USB-related limitations and ensures reliable UPS monitoring across the cluster.

2️ If USB is the Only Option

  • Instead of a USB hub, connect the UPS to a single node via USB.
  • Configure this node as the NUT Master (server), and the other nodes as NUT Clients.
  • When the UPS battery drains, the NUT Master will send shutdown commands to all nodes.

3️ Eaton vs. APC?

  • Eaton: Generally better NUT compatibility, good Linux support, and excellent battery life.
  • APC: Well-known, but APC USB protocols can be less reliable with NUT.
  • Recommendation: If using NUT, Eaton is usually the better choice.

Final Suggestion:

✅ Best Option: Network-based UPS with NUT over SNMP.
✅ If USB-only: Direct USB to one node → NUT Master/Client setup.
✅ UPS Choice: Eaton is preferred for better NUT support.