Note: "permalinks" may not be as permanent as we would like,
direct links of old sources may well be a few messages off.
1.7.2011 16:43, Helmut Wollmersdorfer kirjoitti: > > Am 24.06.2011 um 16:58 schrieb Whit Blauvelt: > >> I truly appreciate that, Pete. What I've been hoping to find is >> distribution-neutral models for handling KVM failover, where each KVM >> VM is >> directly on top of a dedicated DRBD resource - which is a setup with an >> ideal granularity, as compared to having multiple VMs sharing a >> single DRBD >> resource. Because the granularity is right-sized, it greatly >> simplifies the >> possible failure modes, and what should be needed for reliable >> failover. For >> example, if it were one shared DRBD resource for many VMs running >> across two >> hosts, it would need to run primary-primary, with CLVM and a >> clustering file >> system and the full pacemaker-corosync/heartbeat treatment. I get >> that. But >> with dedicated, per-VM DRBD resources, each can be run >> primary-secondary (if >> you don't mind a few seconds down during migration - which will be >> there in >> failover in any case), so there's no need for CLVM or one of the (less >> mature than ext4 or xfs) clustering file systems in the arrangement. > > ACK. Such a configuration should be usual and wide-spread: > A two node cluster with some VMs running criss-cross, each on a > dedicated Primary/secondary DRBD resource. > > One can do it with KVM or Xen or something similar, Primary/Primary > with live-migration, or Primary/Secondary without. > > IMHO it is a very common configuration. > >> There also should be a whole lot less needed on the pacemaker- >> corosync/heartbeat side. What I've been hoping to find is >> documentation on >> just enough of pacemaker-corosync/heartbeat to handle this simplified >> architecture adequately. But most of the documentation isn't aimed >> towards >> an architecture like this at all, and just about nothing I've found >> addresses a KVM environment. > > I join in ranting: there is a lot docs and HOWTOs out there, but > nothing of sufficient quality. > > It still needs many hours (days) of trial and error. > > Here is my crm conf for a similar XEN on dedicated DRBD (shortened to > two VMs): > > node $id="..." xen11 > node $id="..." xen10 > > primitive xen_cmsdb ocf:heartbeat:Xen \ > params xmfile="/etc/xen/cmsdb.cfg" \ > op monitor interval="3s" timeout="30s" \ > op start interval="0" timeout="60s" \ > op stop interval="0" timeout="40s" \ > meta target-role="Started" allow-migrate="false" > primitive xen_www ocf:heartbeat:Xen \ > params xmfile="/etc/xen/www.cfg" \ > op monitor interval="3s" timeout="30s" \ > op start interval="0" timeout="60s" \ > op stop interval="0" timeout="40s" \ > meta target-role="started" allow-migrate="false" > > primitive xen_drbd1_1 ocf:linbit:drbd \ > params drbd_resource="drbd1_1" \ > op monitor interval="15s" \ > op start interval="0" timeout="240s" \ > op stop interval="0" timeout="100s" > primitive xen_drbd1_2 ocf:linbit:drbd \ > params drbd_resource="drbd1_2" \ > op monitor interval="15s" \ > op start interval="0" timeout="240s" \ > op stop interval="0" timeout="100s" > primitive xen_drbd5_1 ocf:linbit:drbd \ > params drbd_resource="drbd5_1" \ > op monitor interval="15s" \ > op start interval="0" timeout="240s" \ > op stop interval="0" timeout="100s" > primitive xen_drbd5_2 ocf:linbit:drbd \ > params drbd_resource="drbd5_2" \ > op monitor interval="15s" \ > op start interval="0" timeout="240s" \ > op stop interval="0" timeout="100s" > > group group_drbd1 xen_drbd1_1 xen_drbd1_2 > group group_drbd5 xen_drbd5_1 xen_drbd5_2 > > ms DrbdClone1 group_drbd1 \ > meta master_max="1" master-mode-max="1" clone-max="2" > clone-node-max="1" notify="true" > ms DrbdClone5 group_drbd5 \ > meta master_max="1" master-mode-max="1" clone-max="2" > clone-node-max="1" notify="true" > > location cli-prefer-xen_cmsdb xen_cmsdb \ > rule $id="cli-prefer-rule-xen_cmsdb" inf: #uname eq xen10 > location cli-prefer-xen_www xen_www \ > rule $id="cli-prefer-rule-xen_www" inf: #uname eq xen11 > > location prefer_xen10_cmsdb xen_cmsdb 50: xen10 > location prefer_xen10_www xen_www 40: xen10 > > location prefer_xen11_cmsdb xen_cmsdb 40: xen11 > location prefer_xen11_www xen_www 50: xen11 > > colocation xen_cmsdb_and_drbd inf: xen_cmsdb DrbdClone5:Master > colocation xen_www_and_drbd inf: xen_www DrbdClone1:Master > > order xen_cmsdb_after_drbd inf: DrbdClone5:promote xen_cmsdb:start > order xen_www_after_drbd inf: DrbdClone1:promote xen_www:start > > property $id="cib-bootstrap-options" \ > dc-version="1.0.9-74392a28b7f31d7ddc86689598bd23114f58978b" \ > cluster-infrastructure="Heartbeat" \ > stonith-enabled="false" \ > no-quorum-policy="ignore" \ > last-lrm-refresh="1309523267" > > rsc_defaults $id="rsc-options" \ > resource-stickiness="100" > > HTH > > Helmut Wollmersdorfer > > _______________________________________________ > drbd-user mailing list > drbd-user at lists.linbit.com > http://lists.linbit.com/mailman/listinfo/drbd-user I have similar setup, and have draft for howto + GUI script. https://github.com/joukoy/KVM-cluster-tool This is still far from perfect but it works for me. Any feedback about script or howto is welcome. If you think it's totally useless, please tell me. Maybe I destroy it from github then :-) (not) - Jouko -