swarmctl CLI gains --tls/--cert/--key/--client-ca flags. With --tls the
controller runs uvicorn under HTTPS + mTLS (CERT_REQUIRED) so worker
heartbeats can reach it cross-host. Default is still 127.0.0.1 plaintext
for backwards compat with the master-CLI enrollment flow.
Auto-issue path (no --cert/--key given): a server cert signed by the
existing DECNET CA is issued once and parked under ~/.decnet/swarmctl/.
Workers already ship that CA's ca.crt from the enroll bundle, so they
verify the endpoint with no extra trust config. BYOC via --cert/--key
when the operator wants a publicly-trusted or externally-managed cert.
The auto-cert path is idempotent across restarts to keep a stable
fingerprint for any long-lived mTLS sessions.
decnet.swarm.pki provides:
- generate_ca() / ensure_ca() — self-signed root, PKCS8 PEM, 4096-bit.
- issue_worker_cert() — per-worker keypair + cert signed by the CA with
serverAuth + clientAuth EKU so the same identity backs the agent's
HTTPS endpoint AND the syslog-over-TLS upstream.
- write_worker_bundle() / load_worker_bundle() — persist with 0600 on
private keys.
- fingerprint() — SHA-256 DER hex for master-side pinning.
tests/swarm/test_pki.py covers:
- CA idempotency on disk.
- Signed chain validates against CA subject.
- SAN population (DNS + IP).
- Bundle roundtrip with 0600 key perms.
- End-to-end mTLS handshake between two CA-issued peers.
- Cross-CA client rejection (handshake fails).
