Three load-bearing fixes that together let `banger update` (and its
auto-rollback path) restart the helper + daemon without killing
every running VM. New smoke scenarios prove the property end-to-end.
Bug fixes:
1. Disable the firecracker SDK's signal-forwarding goroutine. The
default ForwardSignals = [SIGINT, SIGQUIT, SIGTERM, SIGHUP,
SIGABRT] installs a handler in the helper that propagates the
helper's SIGTERM (sent by systemd on `systemctl stop bangerd-
root.service`) to every running firecracker child. Set
ForwardSignals to an empty (non-nil) slice so setupSignals
short-circuits at len()==0.
2. Add SendSIGKILL=no to bangerd-root.service. KillMode=process
limits the initial SIGTERM to the helper main, but systemd
still SIGKILLs leftover cgroup processes during the
FinalKillSignal stage unless SendSIGKILL=no.
3. Route restart-helper / restart-daemon / wait-daemon-ready
failures through rollbackAndRestart instead of rollbackAndWrap.
rollbackAndWrap restored .previous binaries but didn't re-
restart the failed unit, leaving the helper dead with the
rolled-back binary on disk after a failed update.
Testing infrastructure (production binaries unaffected):
- Hidden --manifest-url and --pubkey-file flags on `banger update`
let the smoke harness redirect the updater at locally-built
release artefacts. Marked Hidden in cobra; not advertised in
--help.
- FetchManifestFrom / VerifyBlobSignatureWithKey /
FetchAndVerifySignatureWithKey export the existing logic against
caller-supplied URL / pubkey. The default entry points still
call them with the embedded canonical values.
Smoke scenarios:
- update_check: --check against fake manifest reports update
available
- update_to_unknown: --to v9.9.9 fails before any host mutation
- update_no_root: refuses without sudo, install untouched
- update_dry_run: stages + verifies, no swap, version unchanged
- update_keeps_vm_alive: real swap to v0.smoke.0; same VM (same
boot_id) answers SSH after the daemon restart
- update_rollback_keeps_vm_alive: v0.smoke.broken-bangerd ships a
bangerd that passes --check-migrations but exits 1 as the
daemon. The post-swap `systemctl restart bangerd` fails,
rollbackAndRestart fires, the .previous binaries are restored
and re-restarted; the same VM still answers SSH afterwards
- daemon_admin (separate prep): covers `banger daemon socket`,
`bangerd --check-migrations --system`, `sudo banger daemon
stop`
The smoke release builder generates a fresh ECDSA P-256 keypair
with openssl, signs SHA256SUMS cosign-compatibly, and serves
artefacts from a backgrounded python http.server.
verify_smoke_check_test.go pins the openssl/cosign signature
equivalence so the smoke release builder can't silently drift.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Thales Maciel
2606bfbabb