It’s hard to find root cause and fix something in libvirt, even we found the root cause, it's hard to push the fix into libvirt upstream, and not to say push into downstream, like RHEL 6 etc. For example, we already have a fix for the bug https://bugzilla.redhat.com/show_bug.cgi?id=977706 for a few month now, there is no resolution to resolve the issue. Without the fix, we just simply are blocked to support newer version of KVM.
So if community doesn't like what I proposed, then how about another way: I will write a new implementation of KVMStoragePool interface, which will be backed by java/python/shell script, it won't be enabled by default. It's a simple thing, don't understand why libvirt gets it done so complicated, and introduce a lot of pain. > -----Original Message----- > From: Nux! [mailto:n...@li.nux.ro] > Sent: Wednesday, March 19, 2014 12:35 PM > To: dev@cloudstack.apache.org > Subject: Re: [RFC]Bypass Libvirt storage pool for NFS > > On 19.03.2014 19:01, Wido den Hollander wrote: > > On 03/19/2014 07:54 PM, Edison Su wrote: > >> I found many times in QA's testing environment, the libvirt storage > >> pool(created on NFS) is missing on the kvm host frequently, for no > >> reason. It may relate to bug > >> https://bugzilla.redhat.com/show_bug.cgi?id=977706. > >> In order to fix this issue, and bug CLOUDSTACK-2729, we added a lot > >> of workaround to fight with libvirt, such as, if can't find the > >> storage pool, then create the same pool again etc. As the storage > >> pool can be lost on kvm host at any time, it will cause a lot of > >> operation errors, such as can't start vm, can't delete volume etc, etc. > >> I want to bypass libvirt storage pool for NFS, as java itself, > >> already have all the capabilities that libvirt can provide, such as > >> create a file, delete a file, list a directory etc, there is no need > >> to add another layer of crap here. In doing so, we won't be blocked > >> by libvirt bug(https://bugzilla.redhat.com/show_bug.cgi?id=977706) to > >> support newer version of KVM. > >> > > > > -1 > > > > I understand the issues which we see here, but imho the way forward is > > to fix this in libvirt instead of simply go around it. > > > > We should not try to re-invent the wheel here, but fix the root-cause. > > > > Yes, Java can do a lot, but I think libvirt can do this better. > > > > For the RBD code I also had a couple of changes go into libvirt > > recently and this NFS issue can also be fixed. > > > > Loosing NFS pools in libvirt is most of the times due to a restart of > > libvirt, they don't magically disappear from libvirt. > > > > I agree that we should be able to start the pool again even while it's > > mounted, but that's something we should fix in libvirt. > > > > Wido > > -1 and 100% with Wido. If libvirt gets fixed then it would save loads of code > in > the future and bring other benefits (think support for Xen Project via libvirt > etc). > Let's push for libvirt fix instead. > > My 2 cents, > Lucian > > > -- > Sent from the Delta quadrant using Borg technology! > > Nux! > www.nux.ro
