[SOLVED] High Availability - 4 nodes - only 2 active at the time

[Rogaty_Brodaty]

Hello there,

As a new user of Proxmox, I’d like to ask for guidance or a tutorial on how to configure High Availability (HA) so that only two nodes are active at any given time.

I have a 4-node cluster, but currently, only one node hosts VMs. To optimize power consumption, I want to shut down two of my nodes when they are not needed. My goal is to have the cluster automatically boot one of the standby nodes (e.g., Node 3) if one of the active nodes (e.g., Node 1) shuts down or fails.

Additionally, I expect that once the original nodes come back online, the system will automatically shut down the VMs running on the standby node and move them back to the original nodes.

Could someone explain how to set this up, or point me toward relevant documentation?

Thank you!

 

[Daniel_Dog]

I hate to be that guy but this is not NOT SUPPORTED.

for a HA cluster you need at least 3 active nodes at all times. (But it is recommended to have 4 or more.)
https://pve.proxmox.com/wiki/Cluster_Manager

And also there is no build-in way to turn on a node when an other node goes offline.
This may be possible with WoL (Wake-on-LAN) but you will need to make something yourself that works.

 

[Rogaty_Brodaty]

Got Ya, thank you

 

[Daniel_Dog]

Your welcome.

 

[UdoB]

Could someone explain how to set this up, or point me toward relevant documentation?

--> https://pve.proxmox.com/pve-docs/pve-admin-guide.html#_qdevice_technical_overview

With an additional Quorum Device (a VM on a NAS or a Raspberry Pi or ...) you can extend your 4 nodes to 5 votes. Then you can have two nodes failed (or intentionally shut down) and the Quorum condition "more than half of the votes are necessary" can still be fulfilled.

Of course with two nodes + QDev "up" you are at the lowest allowed limit, but hey... for a Homelab it may be okay.


Edit: with a third node going down the single remaining node will reboot if HA is enabled. As you will boot a spare node I would consider this a good thing...