After uploading/adding a virtual machine image to Glance, it is not possible to modify the actual virtual machine image -- images are read-only after all --however, it is possible to update any metadata about the image after you add it to Glance.

The update command allows you to update the metadata fields of a stored image. You use this command like so:

glance update <ID> [field1=value1 field2=value2 ...]

Let's say we have an image with identifier 5 that we wish to change the is_public attribute of the image from False to True. The following would accomplish this:

$> glance update 5 is_public=true --host=65.114.169.29
Updated image 5

Using the --verbose flag will show you all the updated data about the image:

$> glance --verbose update 5 is_public=true --host=65.114.169.29
Updated image 5
Updated image metadata for image 5:
URI: http://example.com/images/5
Id: 5
Public? Yes
Name: My Image
Size: 58520278
Location: file:///tmp/images/5
Disk format: raw
Container format: ovf
Completed in 0.0596 sec.


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