Boot and Runtime

Kernel Selection

Launcher preference:

If LaunchSpec.KernelOverride set → use that path

Else if Initramfs present → use vmlinux (uncompressed)

Else → use bzImage (compressed)

Code: internal/server/orchestrator/cloudhypervisor/launcher.go (kernelSrc selection)

Initramfs

Manifest.Initramfs.url → required

Optional checksum (sha256:...)

Fastest boot path; pairs well with kestrel agent

RootFS

Manifest.RootFS.url → required

Optional checksum (sha256:...)

Attached as writable disk; default device/fstype set when missing (vda/ext4)

When configured (manifest or overrides), cloud-init NoCloud is built and attached as read-only disk (CIDATA)

Code: internal/server/orchestrator/cloudinit/builder.go

Inputs: user-data, meta-data, optional network-config

Base args set by orchestrator (ip=... if managed, console, panic, etc.)

Additional runtime args from pluginspec constants (runtime, api_host, api_port, plugin, encoded manifest)

Code: orchestrator.go buildKernelCmdline/appendKernelArgs, launcher assembles --cmdline

Cloud Hypervisor process managed by runtime.Instance

Wait channel for exit, graceful termination (SIGTERM, then SIGKILL on timeout)

Serial console via UNIX socket per VM

Artifacts cleaned on stop (kernel/initramfs/rootfs/serial)