Unable to Migrate Instance as Image Used to Create Instance is Deleted

Problem

Unable to migrate the instance as the original image used to create the instance is deleted.

Environment

• Platform9 Managed OpenStack - All Versions
• Nova
• Glance
• QEMU

Cause

The instance cannot be resized or migrated as the image is deleted from the Glance node.

Note: If the backing file is not present on the hypervisor running the instance, the image cannot be recreated.

Resolution

1. Execute the following command on the hypervisor running the instance to check if the backing file is present or not.

$ sudo qemu-img info [INSTANCE_STORAGE_PATH]/[INSTANCE_UUID]/disk

2. Copy the backing file to the /tmp directory of the Glance node in your environment.
3. Check the file format of the backing file.

$ qemu-img info /tmp/backing_file

4. If the backing file is in raw format, convert it into qcow2 format.

$ qemu-img convert -f raw -O qcow2 [backing_file_name] [original_image_name]

5. Change ownership of the file 'original_image_name'.

$ chown pf9:pf9group filename

6. Check the integrity of the image rebuilt by creating a test instance.