[Nut-upsuser] NUT configuration complicated by Stonith/Fencing cabling

[Roger Price]

On Sun, 5 Feb 2017, Tim Richards wrote:

> Setup: Active/Passive Two Node Cluster. Two UPSes (APC Smart-UPS 1500 C) 
> with USB communication cables cross connected (ie UPS-webserver1 
> monitored by webserver2, and vice versa) to allow for stonith/fencing
> 
> OS OpenSuse Leap 42.2
> NUT version 2.7.1-2.41-x86_64
> Fencing agent: external/nut
> 
> Problem: When power fails to a single UPS, both nodes are shutdown. The 
> node with the still powered UPS comes back up, but requires manual 
> intervention to keep it providing services. I would like only the node 
> with the “On Battery” UPS to shutdown.

I think your title hints at the solution.  What is the advantage of the 
cross-connection of the UPS units?  Wouldn't it be simpler to have each 
node connected to the UPS which supplies the power?  This is easier to set 
up, extends easily to n servers, and is independent of the stonith/fencing 
which I assume you use for other purposes.

> The resupply of services problem seems to be that NUT on the node that 
> comes back up will not restart until the other node restarts.

With a simpler setup, this problem should go away.

Roger