1 Reply Latest reply: Jul 5, 2017 2:41 AM by nuno.melo RSS

BE6K running stock CUCM 11.0 and auto-shutdown via UPS signalling?


Hi everyone,


This has been an on-going hassle with TAC around something so simple: BE6K running stock CUCM 11.0 stack (CNX and CUCM) and needing the standard protection of auto-shutdown via UPS signalling (via IP not a serial cable)?


For some reason there's drama around the issue; why? I'm not trying to somehow interface the UPS with the BE6K bare metal since that won't do any good anyway - I want the ESXi VMs shutdown gracefully and not the bare metal cutting power on its own via some imaginary integration with CMC. That's what TAC seems to misunderstand over and over and for once accurately communicate that such integration isn't possible.


I know that the unified OS is not to be touched and we don't have root access to it anyway (to install UPS agents) so then why is it so hard to simply run APC's PCNS VM appliance which monitors the UPS via IP and then shuts down ESXi when needed?


That piece is very hard to get across since the question is simply whether that's kosher with TAC in terms of strategy? In other words the above described setup works like a charm in context of engineering but I want to make sure that in the other context: support and SmartNet biz that solution is acceptable. I don't want to get a case going on something completely unrelated and if they figure out that there's another VM (the PCNS appliance) running on the ESXi box (which runs on the BE6K) and start grasping for straws and excuses that this isn't "supported"...

Anyone out here doing the most normal of things: interface a UPS with CUCM to trigger graceful shutdown in case of a power outage?




  • 1. Re: BE6K running stock CUCM 11.0 and auto-shutdown via UPS signalling?

    From my Experience, since UC moved to Virtualized environment the gracefull shutdown of the UC Vms is not very reliable, you can use APC PCNS VM solution to try to gracefully shutdown the Vms on a BE6k. I don't think you will run into "unsupported" issues. However if by any chance PCNS shuts down the machines un-cleanlly which may cause system issues then TAC man not support you.


    The issue with PCNS on a VM on BE6K is the following:


    1 - If you have hardware/Software failures on the UCS server the Esxi hypervisor sometimes may just freezes so it will not proceed with the  clean shutdown since the PCNS is also a VM which co-exists with within the Esxi Hypervisor

    2 -  Even if there are not issues with the Hardware , it may happen that the CUCM when commanded to gracefully shutdown it will not do to a hug process, when this happens it will request confirmation on the shutdown, if none is given the VM will not shutdown, if PCNS forces the shutdown in this situation , the VM will shutdown un-cleanly and therefore may corrupt the file system.


    Regarding the CIMC which resides on the UCS some versions have a power management option which allow a graceful shutdown of the server if you have a redundant PSU, and 1 of the PSUs is not provided power (so no need of very complex integrations here, pic bellow). however also in this case if the VM is not able to preform a graceful shutdown because of a hung process the shutdown will unclean and it may generate a corrupt filesystem.


    in CIMC you can use the Power Supply Redundancy Lost Filter


    However if the possibility of an un-clean shutdown of VMs is not a problem I have found that the UPS PCNS or CIMC option are valid.