Images

An image is a bootable disk that instances launch from. Every image has an owner project and a visibility: private to its project, shared with named projects, or public. Operator images (global scope) are visible to every project.

Base images

The install registers no images. The catalog of base images is there to add from. Each entry is pinned to one dated upstream build by URL, size and SHA-256:

Name	Image
almalinux-10-genericcloud	AlmaLinux 10 GenericCloud
ubuntu-26-04-cloud	Ubuntu 26.04 LTS
debian-13-genericcloud	Debian 13 GenericCloud
centos-stream-10-genericcloud	CentOS Stream 10 GenericCloud

stratumctl admin images catalog                                      # each entry and its state
stratumctl admin images catalog add ubuntu-26-04-cloud debian-13-genericcloud

Console: Admin › Platform › Catalog › Global Images › Add base images. Adding an entry downloads it, checks its size and SHA-256 before anything is written, and imports it. Without internet access the download fails within seconds with a short reason; add it again once the node can reach the internet, or upload the file. New pins arrive with upgrades.

Upload a file

Your own qcow2 or raw image, from your machine. This is the way on a site without internet access:

stratumctl images upload --file ./debian-13-genericcloud-amd64.qcow2 --name debian-13 \
  --os-family linux --os-distro debian --os-version 13 --sha256 <sha256 of the file>

The control plane checks the file (the SHA-256 when given, and that it is qcow2 or raw with no backing file) and imports it into the default storage class, or the one named with --storage-class. Console: Admin › Platform › Catalog › Global Images › Upload image.

Import from a URL

Any qcow2 or raw image the node can download:

stratumctl images import --name debian-13 --display-name "Debian 13" \
  --url https://cloud.debian.org/images/cloud/trixie/latest/debian-13-genericcloud-amd64.qcow2 \
  --format qcow2 --os-family linux --os-distro debian --os-version 13 \
  --sha256 <sha256 of the file>

The image is converted to raw on the storage pool and becomes active when the import finishes. On a site without internet access, put the file on a local web server and import it from there, with its SHA-256.

Tenant images

Tenants make their own images and decide who sees them:

stratumctl images create-from-instance --instance i-abc123 --name web-golden --project p-web
stratumctl images share img-abc123 --with p-other --project p-web
stratumctl images deprecate img-abc123 --at 2027-01-01T00:00:00Z --project p-web

By default the capture stops the instance, snapshots its disks and starts it again. --no-reboot keeps it running and asks the guest agent to freeze the filesystems for the snapshot; without the agent the image is crash-consistent.

An image can be deprecated on a date, disabled, and deleted with or without its snapshots.