[Users] Two fence devices per server.
Just installed the latest oVirt, must admit you guys have done a great job. One issue I am having tho is that with my setup each server has 2 power supplies and the two supplies are one two different APC power strips. Is there any way to configure fencing to work with two devices per server?
<> Nathan Stratton CTO, BlinkMind, Inc. nathan at robotics.net nathan at blinkmind.com http://www.robotics.net http://www.blinkmind.com
On 11/02/12 01:07, Nathan Stratton wrote:
Just installed the latest oVirt, must admit you guys have done a great job. One issue I am having tho is that with my setup each server has 2 power supplies and the two supplies are one two different APC power strips. Is there any way to configure fencing to work with two devices per server?
Hi Nathan, Currently OE (oVirt engine) supports only one power management device per server. Livnat
<> Nathan Stratton CTO, BlinkMind, Inc. nathan at robotics.net nathan at blinkmind.com http://www.robotics.net http://www.blinkmind.com
Users mailing list Users@ovirt.org http://lists.ovirt.org/mailman/listinfo/users
On Sun, 12 Feb 2012, Livnat Peer wrote:
Hi Nathan,
Currently OE (oVirt engine) supports only one power management device per server.
Most servers today take more then one power supply, in fact none of ours even come with 1 supply options. How are people dealing with this problem today? Is it possible to put both supplies on one strip and use oVirt to fence both outlets? If not, are people using some other device to feed multiple supplies from one outlet? We have looked at IPMI fence, but we have found it not to be very reliable.
Livnat
<> Nathan Stratton CTO, BlinkMind, Inc. nathan at robotics.net nathan at blinkmind.com http://www.robotics.net http://www.blinkmind.com
On 02/12/2012 11:18 AM, Nathan Stratton wrote:
On Sun, 12 Feb 2012, Livnat Peer wrote:
Hi Nathan,
Currently OE (oVirt engine) supports only one power management device per server.
Most servers today take more then one power supply, in fact none of ours even come with 1 supply options. How are people dealing with this problem today? Is it possible to put both supplies on one strip and use oVirt to fence both outlets? If not, are people using some other device to feed multiple supplies from one outlet?
It is possible to put both power supplies on a single external APC device, however that sort of negates the redundancy of having dual power supplies (to some degree). Ideally you'd want each power supply on a separate circuit and putting them on the same circuit means that both power supplies will fail if the circuit fails. I think that oVirt Engine needs the ability to configure more than one fencing device per server, with logic to determine if either fence device is sufficient to power off the machine, or if both are required. The cluster stack (rgmanager or pacemaker based) in Fedora and other distributions contains this sort of logic. So in those software systems you could create two (or more) fence devices per host with boolean logic like: fence_apc APC1 && fence_apc APC2 This means that in order for fencing to be successful, both devices must be successfully powered off. This would handle a dual power supply situation (dual primary) vs. fence_ipmi || fence_apc This would be used in a situation where the ipmi device is the primary fencing device and if that succeeds, there is no need to issue the fence_apc command. (single primary with backup) So similar logic is probably needed in oVirt. Probably would be appropriate to file an RFE here.
We have looked at IPMI fence, but we have found it not to be very reliable.
IPMI is a protocol/standard that is implemented by many different hardware devices. Which specific hardware device were you using? What made you think it was unreliable? Also note that there are many BMC style fencing devices out there so you're not necessarily restricted to just using the IPMI protocol. Many people use IPMI based fence devices in production HA clusters, and by and large I haven't heard a lot of complaints about them. Perry
participants (3)
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Livnat Peer -
Nathan Stratton -
Perry Myers