Goal:

Customers are in need to be able to change the current glance image storage backend to a different one, such as from CEPH to S3. This should be possible for existing installations where changing backends is currently not supported by Red Hat.

Acceptance Criteria:

• Customer can change the current CEPH backend to S3 for an existing installation.
• A clear way to migrate the images is present and documented.
• Impact on existing workload is minimal.

Additional Information:

From discussions about this issue, the following high-level steps where discussed:

• Enabling multistore to mirror images
• Enable copy_image import method
• Copy image from CEPH to S3 which will keep same image id and properties
• Delete image from CEPH
• Remove CEPH backend from configuration
• To actually copy image a command as follows could be possible:
  • glance image-import --import-method copy-image --stores store1,store2 image-id