Cloud-Init - Volant

References: internal/server/orchestrator/cloudinit/builder.go and orchestrator.go (prepareCloudInitSeed, mergeCloudInit).

Volant supports NoCloud datasource via a seed image attached as a read‑only disk. You can provide cloud-init documents through the plugin manifest or per‑VM config. The orchestrator merges them and builds a CIDATA image.

Documents

UserData (YAML cloud-config)
MetaData (YAML with instance-id, local-hostname)
NetworkConfig (YAML)

Each document can be provided inline (content) or via a file path (path). When a path is given, the CLI resolves relative paths based on the manifest file location and inlines the content.

Merging rules

Effectively: override wins. The orchestrator uses mergeCloudInit(base, override):

If override content/path set or inline=true, override replaces base for that document.
Otherwise base is kept.

Base comes from the plugin manifest (if any). Override comes from per‑VM config.

Seed build

The orchestrator creates a seed image at ~/.volant/run/cloudinit/-seed.img:

If cloud-localds exists, it is used with the provided documents.
Otherwise, a VFAT image is created with go-diskfs and the files are written manually.
The volume label is CIDATA.

MetaData defaults are synthesized if not provided:

instance-id: volant-
local-hostname:

Cleanup and updates

On VM start or create, the seed is generated and attached as a read-only disk.
On config changes, seeds are rebuilt and old seeds removed.
On VM deletion, the seed image is removed.

Authoring tips

Keep cloud-config minimal for initramfs; the agent typically manages services and workload.
For oci_rootfs, use cloud-init to write config files or manage system users/services as needed.