The SSP disk driver cleverly avoids uploading a particular glance image
to the SSP more than once by naming it such that it can be recognized
subsequently. If the image LU thus named already exists in the SSP, we
reuse it (creating a linked clone for use by the instance being
deployed).
Previously, the naming convention for an image LU was
'image_%(sanitized_image_name)s', where the sanitized_image_name was
generated from the first 73 characters of the glance image name (79,
which is the default max filename size, minus the length of 'image_'),
scrubbed to replace any non-alphanumeric/period/underscore characters
with underscores.
This will cause problems whenever an image name is reused while the SSP
still contains the original image LU: the SSP disk driver will generate
the same name, find an image LU of that name in the SSP, and blithely
attach the deploying instance to a linked clone of that image, even
though it's not the same as the new one in glance.
To remedy this problem, with this change set we are now generating the
image LU name as 'image_%(sanitized_image_name)_%(image_checksum)s'.
The image_checksum is a 32-character hash that comes from ImageMeta.
The total length is still 79; so the 'sanitized_image_name' is now
limited to 40 characters.
Now, even when an image name is reused, the LU name will (with extremely
high probability, like reaching into your average star twice and getting
two different milligrams of matter) be different because the image's
checksum will be different; so we'll upload and use the new image
instead of the old one.
Change-Id: I465a90e7105d7d8a7ed1e0b30e96ee98a1d7dfdb
edf7367ed5