Use OpenStack Swift as a Backend Store for Glance

Sunday, August 3, 2014

By default, OpenStack Glance saves images and OpenStack Instance snapshots on the local filesystem in /var/lib/glance/images/.

However, if you have a Swift Cluster, you can just as easily use it to save images and snapshots instead of the local filesystem where Glance is running.

Begin by logging into the node running the Glance services (probably your controller node also running Keystone) as root and source your OpenStack credentials (this is typically a file named openrc).

source ~/openrc

Verify the user glance is part of tenant service with role admin.

keystone user-role-list --user glance --tenant service

One of the roles returned should be admin.

Open /etc/glance/glance-api.conf and comment out the following two lines:

##### DEFAULT OPTIONS #####
#default_store = file
#filesystem_store_datadir = /var/lib/glance/images/

With /etc/glance/glance-api.conf still open, append the following lines to the DEFAULT OPTIONS section (be sure to set the values inside < > to match your environment):

default_store = swift
swift_store_auth_address = http://<IP_OF_KEYSTONE>:35357/v2.0/
swift_store_user = service:glance
swift_store_key = <VALUE OF __admin_password__ ATTRIBUTE IN __/etc/glance/glance-api.conf__>
swift_store_create_container_on_put = True

With the configuration changes in place, restart the Glance services.

If you are running CentOS/RHEL:

service openstack-glance-api restart

service openstack-glance-registry restart

If you are running Ubuntu:

service glance-api restart

service glance-registry restart

Now you should be able to upload an image to Glance through the Horizon Dashboard or using the glance command and instead of it being saved to /var/lib/glance/images, it will be saved in a Swift Container called glance in the service account.

Verify nothing is saved in /var/lib/glance/images by simply running ls /var/lib/glance/images (if you did not delete any existing Glance Images, they will still be there).

Once the Horizon Dashboard or the glance image-list reports the image is active, you can verify the images are in Swift by running the following command (be sure to set the values inside < > to match your environment):

swift --os-auth-url http://<IP_OF_KEYSTONE>:5000/v2.0 --os-tenant-name service --os-username glance --os-password <PASSWORD USED IN swift_store_key ABOVE> list glance

References

OpenStack Glance - Use Swift as backend



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