Note: "permalinks" may not be as permanent as we would like,
direct links of old sources may well be a few messages off.
On 05/07/13 06:14, Jarno Elonen wrote: > Hi, > > I've got a very nicely running DRBD setup with Pacemaker and XEN, and > would next like to add some live migration to the soup. > > 1) Is there a Pacemaker script (ocf?) that could do Xen live migration > through *temporary* dual primary mode? > > 2) Is there a way to check if a resource currently allows two > primaries? (Thinking about shell scripting here.) > > The current DRBD 8.4 documentation suggest configuring the resources > permanently as "allow-two-primaries=yes" for live migration, but I'd > rather avoid that (to prevent accidents like multiple xen startup). > > -Jarno So far as I know, no. It's a planned feature for DRBD 9, but as I understand it, the only way to make DRBD 8 dual-primary is to enable to enable dual-primary in the configuration. Personally, I use dual-primary and clustered LVM with each LV being dedicated to a VM. I copy the VM's XML to a shared directory (on gfs2 in my case), then I undefine the VM (I use KVM, not sure if this maps to Xen). This means that the nodes can't see that the VMs exist, preventing accidental out-of-cluster booting of the VMs. I point the resource manager (I use rgmanager, but I expect it's the same in pacemaker) to the XML definition on the shared directory so the cluster knows how to boot the VM. Lastly, I use robust fencing. So if the nodes lose touch with one another, one of them will be powered off. This prevents split-brains and makes it nearly impossible for a VM to be started on both nodes at once. So dual-primary is safe in this setup. hope this helps... not sure how clear this is... still need my first coffee. :) -- Digimer Papers and Projects: https://alteeve.ca/w/ What if the cure for cancer is trapped in the mind of a person without access to education?