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Why Swift is required in Openstack?

asked 2014-11-27 23:44:00 -0500

Hi I could successfully configure Openstack with Glance and Cinder. Images are getting stored in Glance and Volumes are getting stored in Cinder. Now I can provide Instances and manage them successfully. Now I am still unclear about Necessary of Swift storage in this setup. What is the purpose of Swift Storage ?

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answered 2014-11-28 00:28:33 -0500

updated 2015-07-23 00:30:29 -0500

Swift is an object-storage system to store files and large objects on the cloud using simple APIs. Swift converts every files and objects stored on the cloud to the specifil URL(like:, that your application can retrive files using simple http requests. But in order to use swift in your deployment, your running applications must be cloud-ready application(Cloud-ready means the app is written in a way to use cloud APIs specially swift APIs in this case, or atleast use swift file URLs to retrieve files from cloud instead of local storage). Traditional apps, can not leverage facilities provided by swift, becasue they store/retrive files using operating system APIs.

You didn't need swift becasue your applications are legacy apps that store their files and objects on the local attached virtual disk(provided by cinder), using OS file system APIs instead of cloud storage system(Swift). So, you didn't feel the need of swift.

In summery swift can be used in the following ways:

  • Use as Glance backend to store Images(image is considred as object)
  • Store/Retreive files and objects by cloud-ready applications using swift APIs
  • Store/Retrive cloud backup archives

Hope to be useful.

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Thanks Very much. Yes it is more clear. Can I use Swift for replicating Cinder and Glance across different regions then?

NeeleshG gravatar imageNeeleshG ( 2014-11-28 00:49:05 -0500 )edit

What was the mean of different regions in your comment? Geographically difference(multi-site) or different zone in same location(datacenter)?

Mzoorikh gravatar imageMzoorikh ( 2014-11-28 01:00:24 -0500 )edit

Geographically defferent Regions (Multi-Site).

NeeleshG gravatar imageNeeleshG ( 2014-11-28 01:18:05 -0500 )edit

As I said, swift can be backend for Glance but not for cinder. Cinder use other storage backends such as LVM, GlusterFS, ZFS, Ceph, etc. Yes it is possible to use Swift to replicate Glance image storage backend, into multipe sites in geographically difference. See here.

Mzoorikh gravatar imageMzoorikh ( 2014-11-28 01:50:12 -0500 )edit

Thanks very much for your help.

NeeleshG gravatar imageNeeleshG ( 2014-11-28 02:06:50 -0500 )edit

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Asked: 2014-11-27 23:44:00 -0500

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Last updated: Jul 23 '15