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Can the Volume created through cinder-block storage service be exported to a host which is outside the Openstack?

asked 2014-04-03 06:20:34 -0500

San thosh gravatar image


I see APIs in nova to attach a volume to the instance(VM) created within compute node and this API requires server_id (uuid generated by openstack). Can the volume created through cinder be exported(attached) to a Host which is outside the OpenStack.? Or is there a way to register outside host in OpenStack so that it will have server_id which we can use for volume attach operations.

Thanks, Santhosh

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answered 2014-04-03 07:39:10 -0500

larsks gravatar image

There is no facility for either (a) attaching a volume created in Cinder to a non-OpenStack managed host or (b) "registering" hosts with OpenStack.

You could manually (not through an API) expose a Cinder volume to arbitrary hosts, but this would lead only to confusion and sadness.

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thanks for the information.

San thosh gravatar imageSan thosh ( 2014-04-03 12:21:27 -0500 )edit

answered 2014-04-29 07:44:50 -0500

-Disclosure NetApp Employee, Opinions Are My Own -

I've been thinking about this possibility for a while after I started doing a TCO analysis of AWS to typical private cloud deployments. One of the interesting points came when comparing the relative simplicity of provisioning an EBS volume to an AWS instance vs provisioning an iSCSI LUN from a NetApp array hosted in the same equinix datacenter (NetApp Private Storage for AWS). In short getting the server admin to communicate things like iSCSI iqn's etc to the storage team (or even entering this information on a self service portal) requires a level of sophistication of the server admin that costs real time and money. In comparison, a fully automated solution hides this complexity, reduces training, setup and tear down times, and eliminates configuration errors by making the new disk device automagically appear.

Having said that, theres no good reason I can think of why you couldn't write a host resident utility that

  1. Calls Cinder via its API, passing connection information such as host name, iSCSI initiator name, FC WWPNs etc
  2. Allowed Cinder to do it's magic
  3. Accepted the connection information returned by Cinder
  4. Creates the connection to the storage using the returned information and return the new device name to the administrator or calling program
  5. Facilitates any further server-level storage admin tasks like adding the new device into a volume group, or laying on a filesystem

Conceptually this is similar to the work done by NetApp's SnapDrive products, especially in combination with the OnCommand. These inexpensive (mostly free) products take away the vast majority of the pain of storage administration from the server admins, but they are designed to work exclusively with ONTAP. Doing something similar that uses Cinder's APIs and drivers to provide similar functionality would be quite cool as it would allow for a nice software defined heterogeneous storage provisioning capability that would work for physical servers, or indeed almost any conceivable infrastructure architecture.

Creating these kinds of OutOfNova Cinder consumers would strengthen Cinder's place as the cornerstone of open source software defined storage, which IMHO would be a good thing.

Having said that, the amount of work that needs to be done would be considerable, and you'd need to sort out things like role based access control, quota management, SLO conformance, and odd client hardware dependencies which are many, varied, and surprisingly expensive to qualify and troubleshoot (e.g. this kind of HBA with this firmware driver on this version of the operating system and that kind of switch don't work unless you set one particular configuration variable).

Given that the rest of the OpenStack work already addresses many of these kinds of issues, you'd have to seriously consider if the result was worth the effort. Even so, the idea still intrigues me.

Regards John Martin

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Asked: 2014-04-03 06:20:34 -0500

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Last updated: Apr 29 '14