On Fri, 2021-04-30 at 07:26 -0700, Matthew Schumacher wrote: > I have an issue that I'm not sure how to resolve so feedback is > welcome. > > I need to mount a local NFS file system on my node before I start a > VirtualDomain resource which depends on it, however, the NFS server > is > itself a resource on the cluster. > > This causes the cart before the horse. If I insert a node into a > running cluster, this is pretty simple, mount nfs before starting > pacemaker, and if a VirtualDomain resource is immediately started, > we > already have what we need. But that doesn't work on a cold cluster > because if I try to mount NFS on the node before the cluster starts > the > NFS server, the mount fails. If I always mount NFS after I start > pacemaker, then pacemaker will usually try to start VirtualDomain > resources before I can get further in the boot and mount NFS which > causes the VirtualDomain resource to fail to start. > > I think I need one of the following fixes: > > 1. Delayed start on VirtualDomain resources so that we give time to > get > the file system mounted which feels hackish as it's the old sleep > fix > for race conditions. > > 2. Make the nfs mount itself a resource and make VirtualDomain > resources depend on it. In order for this to work each node would > need > it's own nfs mount resource, and VirtualDomain resources that can run > on > any node would need to depend on the nfs mount resource of whatever > node > they decide to run on but not the nfs mount resource of any other > node. > I'm not sure how to make this work because the dependency changes > with > what node the VirtualDomain resource is started on.
If each VM needs a particular mount, you can clone the NFS server, create separate groups where groupN = (mountN, vmN), and colocate/order the groups relative to the clone. > 3. Make the VirtualDomain resource call a script on start/migrate > that > simply looks for the nfs mount, and if missing, try to mount. This > seems > less hackish, but will ensure that we always try to get the nfs > mount > going the first time the resource is moved/started there. > > Any ideas or thoughts would be very helpful and appreciated. > > Matt > > > _______________________________________________ > Manage your subscription: > https://lists.clusterlabs.org/mailman/listinfo/users > > ClusterLabs home: https://www.clusterlabs.org/ -- Ken Gaillot <kgail...@redhat.com> _______________________________________________ Manage your subscription: https://lists.clusterlabs.org/mailman/listinfo/users ClusterLabs home: https://www.clusterlabs.org/