_download_cloud_image() cached downloaded images under just the URL's
basename (e.g. ubuntu-26.04-server-cloudimg-amd64.img). Ubuntu's per-build
download URLs change daily under that same stable basename
(.../release-20260713/... vs .../release-20260714/...), so a previous
day's cached file satisfied the "already cached" check and got checksum-
verified against the *new* day's expected hash from NetOrk's daily catalog
sync — failing outright and aborting the whole provisioning job, even
though a plain retry would have re-downloaded and succeeded (the bad file
was already being deleted on mismatch, just never re-fetched).
Found live during a NetOrk deploy: "Checksum mismatch for
https://cloud-images.ubuntu.com/.../release-20260713/
ubuntu-26.04-server-cloudimg-amd64.img: expected 0826c500..., got
3ee4f67f...".
Fix: key the cache path on a hash of the full URL (not just the
basename), and retry the download once after a checksum-mismatch cleanup
before raising.
Christian Manivong
38f0c0a656