Open Stack

mmm... not sure if the concept of oVirt multiple storage domains is
something that can be implemented in Nova as it is, but I would like to
share my thoughts because it's something that -from my point of view-
matters.

If you want to change the folder where the nova instances are stored you
have to modify the option in nova-compute.conf  'instances_path':

If you look at that folder (/var/lib/nova/instances/ by default) you will
see a structure like this:

drwxrwxr-x   2 nova nova   73 Dec  4 12:16 _base
drwxrwxr-x   2 nova nova    5 Oct 16 13:34 instance-00000002
...
drwxrwxr-x   2 nova nova    5 Nov 26 17:38 instance-0000005c
drwxrwxr-x   2 nova nova    6 Dec 11 15:38 instance-00000065

If you have a shared storage for that folder, then your fstab entry looks
like this one:
10.15.100.3:/volumes/vol1/zone1/instances /var/lib/nova/instances nfs
defaults 0 0

So, I think that it could be possible to implement something like 'storage
domains', but tenant/project oriented. Instead of having multiple generic
mountpoints, each tenant would have a private mountpoint for his/her
instances. So the /var/lib/nova/instances could look like this sample:

/instances
+/tenantID1
++/instance-0000X
++/instance-0000Y
++/instance-0000Z
+/tenantID2
++/instance-0000A
++/instance-0000B
++/instance-0000C
...
+/tenantIDN
++/instance-0000A
++/instance-0000B
++/instance-0000C

And in the /etc/fstab something like this sample too:
10.15.100.3:/volumes/vol1/zone1/instances/tenantID1
/var/lib/nova/instances/tenantID1 nfs defaults 0 0
10.15.100.3:/volumes/vol1/zone1/instances/tenantID2
/var/lib/nova/instances/tenantID2 nfs
defaults 0 0
...
10.15.100.3:/volumes/vol1/zone1/instances/tenantIDN
/var/lib/nova/instances/tenantIDN nfs defaults 0 0

With this approach, we could have something like per tenant QoS on shared
storage to resell differente storage capabilities on a tenant basis.

I would love to hear feedback, drawback, improvements...

Cheers
Diego

 --
Diego Parrilla
<http://www.stackops.com/>*CEO*
*www.stackops.com | * diego.parrilla at stackops.com** | +34 649 94 43 29 |
skype:diegoparrilla*
* <http://www.stackops.com/>
*

*




On Thu, Dec 20, 2012 at 4:32 PM, Andrew Holway <a.holway at syseleven.de>wrote:

> Good plan.
>
>
> https://blueprints.launchpad.net/openstack-ci/+spec/multiple-storage-domains
>
>
> On Dec 20, 2012, at 4:25 PM, David Busby wrote:
>
> > I may of course be entirely wrong :) which would be cool if this is
> achievable / on the roadmap.
> >
> > At the very least if this is not already in discussion I'd raise it on
> launchpad as a potential feature.
> >
> >
> >
> >
> > On Thu, Dec 20, 2012 at 3:19 PM, Andrew Holway <a.holway at syseleven.de>
> wrote:
> > Ah shame. You can specify different storage domains in oVirt.
> >
> > On Dec 20, 2012, at 4:16 PM, David Busby wrote:
> >
> > > Hi Andrew,
> > >
> > > An interesting idea, but I am unaware if nova supports storage
> affinity in any way, it does support host affinity iirc, as a kludge you
> could have say some nova compute nodes using your "slow mount" and reserve
> the "fast mount" nodes as required, perhaps even defining separate zones
> for deployment?
> > >
> > > Cheers
> > >
> > > David
> > >
> > >
> > >
> > >
> > >
> > > On Thu, Dec 20, 2012 at 2:53 PM, Andrew Holway <a.holway at syseleven.de>
> wrote:
> > > Hi David,
> > >
> > > It is for nova.
> > >
> > > Im not sure I understand. I want to be able to say to openstack;
> "openstack, please install this instance (A) on this mountpoint and please
> install this instance (B) on this other mountpoint." I am planning on
> having two NFS / Gluster based stores, a fast one and a slow one.
> > >
> > > I probably will not want to say please every time :)
> > >
> > > Thanks,
> > >
> > > Andrew
> > >
> > > On Dec 20, 2012, at 3:42 PM, David Busby wrote:
> > >
> > > > Hi Andrew,
> > > >
> > > > Is this for glance or nova ?
> > > >
> > > > For nova change:
> > > >
> > > > state_path = /var/lib/nova
> > > > lock_path = /var/lib/nova/tmp
> > > >
> > > > in your nova.conf
> > > >
> > > > For glance I'm unsure, may be easier to just mount gluster right
> onto /var/lib/glance (similarly could do the same for /var/lib/nova).
> > > >
> > > > And just my £0.02 I've had no end of problems getting gluster to
> "play nice" on small POC clusters (3 - 5 nodes, I've tried nfs tried
> glusterfs, tried 2 replica N distribute setups with many a random glusterfs
> death), as such I have opted for using ceph.
> > > >
> > > > ceph's rados can also be used with cinder from the brief reading
> I've been doing into it.
> > > >
> > > >
> > > > Cheers
> > > >
> > > > David
> > > >
> > > >
> > > >
> > > >
> > > >
> > > > On Thu, Dec 20, 2012 at 1:53 PM, Andrew Holway <
> a.holway at syseleven.de> wrote:
> > > > Hi,
> > > >
> > > > If I have /nfs1mount and /nfs2mount or /nfs1mount and /glustermount
> can I control where openstack puts the disk files?
> > > >
> > > > Thanks,
> > > >
> > > > Andrew
> > > >
> > > > _______________________________________________
> > > > Mailing list: https://launchpad.net/~openstack
> > > > Post to     : openstack at lists.launchpad.net
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> > > >
> > >
> > >
> > >
> >
> >
> >
>
>
>
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