Mailing List Archive

[PackStack][Cinder] On which node OpenStack store data of each instance
Hi,

My question is does OpenStack store volumes somewhere other than
the compute node?
For example in PackStack on two nodes, one for controller and network and
the other for compute node, the instance's volumes will be stored on the
controller or on compute?
Re: [PackStack][Cinder] On which node OpenStack store data of each instance [ In reply to ]
OpenStack stores volumes wherever you configure it to store them. On a
disk array, an NFS server, a Ceph cluster, a dedicated storage node, a
controller or even a compute node. And more.

My guess: Volumes on controllers or compute nodes are not a good
solution for production systems.

By default, Packstack implements Cinder volumes as LVM volumes on the
controller. It's probably possible to put the LVM volumes on other
nodes, and it is definitely possible to configure a different backend
than LVM, for example Netapp, in which case the volumes would be on a
Netapp appliance.

On 11/12/2018 9:34 PM, Soheil Pourbafrani wrote:
> My question is does OpenStack store volumes somewhere other than
> the compute node?
> For example in PackStack on two nodes, one for controller and network
> and the other for compute node, the instance's volumes will be stored
> on the controller or on compute?
Re: [PackStack][Cinder] On which node OpenStack store data of each instance [ In reply to ]
Soheil,

I took the liberty to add the openstack distribution list back in.

Your description is a bit vague. Do you have dedicated nodes for
storage, or do you run instances on the same nodes where storage is
configured? Do you want run use volumes for instance storage, or
ephemeral disks?

Volumes are normally located on remote servers or disk arrays, so that
the answer is yes in this case. You can even pool storage of several
nodes together using DRBD or (up to Newton) GlusterFS, but I have no
experience in this area and can't tell you what would work and what
would not.

To configure volume backends, see
https://docs.openstack.org/cinder/rocky/configuration/block-storage/volume-drivers.html.

Ephemeral storage is normally local storage on the compute node where
the instance runs. You can also use NFS-mounted remote filesystem for
ephemeral storage.

Bernd.

On 11/13/2018 5:37 PM, Soheil Pourbafrani wrote:
> Thanks all,
>
> Suppose we use HDD disks of local machines and there are no shared
> storages like SAN storage. So in such an environment is it possible to
> use remote disks on other machines for compute nodes? (I think it's
> impossible with HDD local disks and for such a scenario we should have
> SAN storage).
>
> So the question is is it possible to have volumes in local disk of
> compute nodes? or we should let OpenStack go!
>
> On Mon, Nov 12, 2018 at 6:31 PM Bernd Bausch <berndbausch@gmail.com
> <mailto:berndbausch@gmail.com>> wrote:
>
> OpenStack stores volumes wherever you configure it to store them.
> On a
> disk array, an NFS server, a Ceph cluster, a dedicated storage
> node, a
> controller or even a compute node. And more.
>
> My guess: Volumes on controllers or compute nodes are not a good
> solution for production systems.
>
> By default, Packstack implements Cinder volumes as LVM volumes on the
> controller. It's probably possible to put the LVM volumes on other
> nodes, and it is definitely possible to configure a different backend
> than LVM, for example Netapp, in which case the volumes would be on a
> Netapp appliance.
>
> On 11/12/2018 9:34 PM, Soheil Pourbafrani wrote:
> > My question is does OpenStack store volumes somewhere other than
> > the compute node?
> > For example in PackStack on two nodes, one for controller and
> network
> > and the other for compute node, the instance's volumes will be
> stored
> > on the controller or on compute?
>