[Kolla][nova] /var/lib/nova/instances on nfs

Sean Mooney smooney at redhat.com
Tue Jun 22 12:32:13 UTC 2021


On Tue, 2021-06-22 at 13:57 +0200, Ignazio Cassano wrote:
> Hello , I am using cinder with netapp driver but if I do not mount a
> share
> under /var/lib/docker/volumes/nova_compute/_data live migration does
> not
> work because an error is disblayed: shared storage in needes or
> something
> like that.
> I do not understand why is does not notice that volumes are shared

so these are cinder boot form volume guests?
if you are usign the correct microverion it should detect that its
shared storage automaticaly when you do a migration can you confirm the
command you are usign to do the migration and that its a boot form
volumen guest not an image backed guest with a data volumn.
> 
> Ignazio
> 
> Il giorno mar 22 giu 2021 alle ore 13:43 Sean Mooney <
> smooney at redhat.com>
> ha scritto:
> 
> > On Tue, 2021-06-22 at 13:02 +0200, Radosław Piliszek wrote:
> > > Hello Ignazio,
> > > 
> > > If you are not using Cinder NFS backend already, you need to set:
> > > 
> > >   enable_shared_var_lib_nova_mnt: yes
> > > 
> > > And yes, you need to manage fstab yourself, mounting the shared
> > > nfs
> > > at
> > > /var/lib/nova/mnt
> > > 
> > > It must happen before the containers are started (so before
> > > deploy or
> > > redeploy).
> > i dont think they were refering to cinder nfs.
> > we have support for deploying novas state directory and libvirts
> > stroage on nfs in nvoa when usign the raw/qcow image backend.
> > 
> > in general i advise against that but it is supported.
> > you should ensure that you use nfs v4 preferable nfs v4.2 or newer
> > 
> > with my downstream hat on we droped supprot for nfs v3 many years
> > ago
> > and the last lts release we hadd that supported it was based on
> > newton.
> > technially we dont have a min nfs version requirement ustream but
> > at
> > some point i think we shoudl enforce at least nfs v4 upstream too.
> > there are several known locking issues with nfs v3 that make it
> > generally problematic to use at scale with nova that manifest
> > intermietnly during move operations.
> > 
> > the same may or may not be true with nfs via cinder but that is one
> > of
> > the less well tested and hardened cinder backends to use with nova.
> > 
> > 
> > > 
> > > -yoctozepto
> > > 
> > > On Tue, Jun 22, 2021 at 12:11 PM Ignazio Cassano
> > > <ignaziocassano at gmail.com> wrote:
> > > > 
> > > > Hello Stackers, is there any configuration parameter in kolla
> > > > for
> > > > sharing nova on nfs between compute nodes ? Or I must insert an
> > > > entry in fstab ?
> > > > Thanks
> > > > Ignazio
> > > > 
> > > 
> > 
> > 
> > 





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