openstack-image-manager

Easily manage and keep up to date a large number of images on an OpenStack environment

Upstream checksum fields

Image versions using the latest pointer must specify where to find the upstream checksum, using exactly one of these two fields:

• checksums_url — URL of a checksums file that contains the image filename, e.g. the SHA256SUMS manifest published by Ubuntu. Lines have the form <digest> <filename>; the line matching the image filename is used.
• checksum_url — URL of a checksum file that contains a single bare digest and nothing else, e.g. the .sha512 sidecar files published by Alpine. Use this when the checksum file does not contain the image filename.

Supported digests are MD5, SHA-1, SHA-256 and SHA-512 (hex-encoded). The checksum URLs must be HTTP(S).

Import path (--prefetch)

By default images are imported with Glance's web-download method, where glance-api fetches the image from its URL itself. When that fetch is slow or flaky, the import can stall and revert to queued. As an alternative the image can be downloaded locally with aria2c (robust multi-connection download with retry and resume) and uploaded via the glance-direct import method, which runs the same decompress/convert/store taskflow as web-download.

--prefetch selects the behaviour:

• never — always use web-download (previous default behaviour).
• on-stuck — default; use web-download first, and fall back to aria2c + glance-direct once if the web-download attempts fail.
• always — skip web-download and use aria2c + glance-direct directly.

--import-timeout (default 1800) bounds the overall per-image wait, shared across all attempts. When a definition carries a checksum, it is passed to aria2c for verification.

The aria2c binary must be installed for the prefetch path, and the target cloud must have the glance-direct import method enabled.

Unlike web-download (where glance-api fetches the image directly), the prefetch path downloads the image to a temporary directory on the host running openstack-image-manager, so that filesystem needs room for the full image (e.g. ~345 MB for the octavia amphora image). A free-space preflight aborts before downloading if the temporary filesystem is too small.