Agent workloads execute model-generated code, so they need a kernel
boundary on top of the app's own sandboxing: Kata plus Firecracker where
hardware virtualisation is available, the gVisor userspace kernel
otherwise, never plain runc.
runsc is fetched as the upstream static release binary with its published
sha512 and the host architecture in the URL, because Debian ships only a
2024 build and Arch and Fedora ship none at all; the same path serves the
arm64 Raspberry Pi target.
select_runtime.yml is a reusable task file: it picks kata only when
/dev/kvm, the kata shim and a bare host all hold. /dev/kvm is visible
inside a Docker-in-Docker daemon through host passthrough, but the microVM
still cannot start there (fuse-overlayfs, no containerd block devices), so
DinD is excluded explicitly and degrades to runsc.
daemon.json gains a runtimes block gated on group membership. Under DinD
runsc additionally needs --network=host: its netstack cannot pluck
interfaces inside a nested netns and aborts with 'cannot run with network
enabled in root network namespace'. The flag keeps the syscall sandbox and
reaches the container netns through real sockets.
The role bootstraps before the service-loader preload, alongside
svc-storage and svc-registry, so the runtime is registered and the daemon
restarted before the first workload compose file renders.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
kevinveenbirkenbachandClaude Opus 4.8