Thanks Martin. That is what I assumed was the case, but got worried when the host could not communicate with the idrac via the 'Test' option in the GUI. I planned to test it when I get a chance by migrating all VMs bar one to the other host, setting the remaining one as HA, and then bringing that host down to see if it gets migrated successfully. I do plan to add a 3rd host.
I was looking at adding an APC agent as well. Can you tell me whether 4.x supports 2 PDUs per host? We have diverse power on each server. I saw a post in 2012 that only one was supported and didn't see an option for adding two slots in the GUI. Thanks, Cam On Sat, Jan 14, 2017 at 12:07 PM, Martin Perina <[email protected]> wrote: > Hi, > > engine executes power management (fencing) operation using different host in > the same cluster/DC as target host reside. It's an oVirt requirement that > each host in the same cluster and data center is able to connect to power > management deviced of all other hosts in the same cluster/DC. > > > Here's simplified flow for defaults (fence proxy may be selected in the same > cluster or DC) > > 1. Find all existing hosts in the same cluster which don't have connection > issues (status Up, Maintenance, NonOperational for a reason different than > network issues) > 2. Select first host in Up (if no host is Up, then pick any other host, if > no host found continue with DC in step 5) and try to execute fence operation > 3. If fence operation is successful, exit > 4. If not, retry 2 times and if still not successful go back to step 2 but > exclude already problematic fence proxy > 5. Find all existing hosts in the same data center which don't have > connection issues (status Up, Maintenance, NonOperational for a reason > different than network issues) > 6. Select first host in Up (if no host is Up, then pick any other host, if > no host found then fail and exit) and try to execute fence operation > 7. If fence operation is successful, exit > 8. If not, retry 2 times and if still not successful go back to step 6 but > exclude already problematic fence proxy > 9. If still no success, fail > > As you see your setup with only 2 hosts is kinda fragile (and not only for > fencing operations), you need to assure that 1 hosts is always in perfect > condition. If possible I'd recommend you to add at least one other host if > possible to make your setup more resistant to failures. > > Martin Perina > > > On Fri, Jan 13, 2017 at 6:10 PM, cmc <[email protected]> wrote: >> >> Hi, >> >> Can someone tell me how the engine decides which power management >> proxy/proxies to use (using default cluster/dc config)? I am using >> drac 7 for a fence agent in my two host cluster, and have noticed that >> one of the hosts cannot contact the drac. My guess is that the engine >> is using one host to as a power management proxy and hosts cannot >> reach their own drac as they are on the same interface + vlan. >> >> Example scenario: >> >> Engine uses host 2 as power management proxy. It can contact host 1’s >> drac, but cannot contact its own drac. In the case of host 2 being >> unreachable/kdumping etc, would the engine switch to use host 1 as the >> proxy to contact host 2’s drac? >> >> Thanks, >> >> Cam >> >> PS: I'd like to use the APC as an additional fencing agent, each host >> has two PSUs connected to two different APCs. Is there a guide on how >> to specify two ports on two different PDUs to control power on a host? >> _______________________________________________ >> Users mailing list >> [email protected] >> http://lists.ovirt.org/mailman/listinfo/users > > _______________________________________________ Users mailing list [email protected] http://lists.ovirt.org/mailman/listinfo/users
