1 Release 15 Tags

RSS Feed

• v0.5.3 17af91a99b

  Compare

  v0.5.3: hub hardening — hard ssh timeout, parallel probes, sticky DOWN cache

  marfrit released this 2026-04-21 11:58:44 +00:00 | 9 commits to master since this release

  Three fixes addressing the recurring "hub wedges on offline backends" class
  of failures (2 incidents in 24h, root-caused to single-threaded Lua + an
  uninterruptible os.execute ssh call):

  1. Hard wall-clock cap on ssh fallback via GNU timeout --kill-after=2 30.
     ConnectTimeout alone only bounds TCP connect; a half-dead sshd (auth
     stall, remote bash-s hang) used to freeze the whole event loop
     indefinitely. Configurable via LMCP_HUB_SSH_HARD_TIMEOUT. Also adds
     ServerAliveInterval=5/Count=2 so an established-but-dead tunnel dies.

  2. Parallel lmcp probes for remote_list_hosts. Shells out a single bash
     fan-out of curl -m 3 calls, bounded by PROBE_BUDGET. Wall clock for a
     full 12-backend probe went from ~28 s (sum of per-host ssh connect
     timeouts) to ~3 s.

  3. Probe is lmcp-only — ssh is no longer used as health check. The hub
     exists to absorb lots of offline hosts, so an expensive ssh per probe
     was the exact wrong tradeoff. Actual remote_* tool calls still fall
     through to ssh fallback when lmcp is down.

  4. Sticky DOWN cache with exponential backoff: 60 → 120 → 240 → 480 →
     900 s. Prevents a sleeping fleet from burning probe budget on every
     health check. UP hosts still use 30 s TTL. Tunable via
     LMCP_HUB_PROBE_TTL_{UP,DOWN_MIN,DOWN_MAX}.

  5. Per-request logging to stderr (tool, host, via, elapsed) — invisible
     before, now captured in journal for the next hang's RCA.

  Co-Authored-By: Claude Opus 4.7 (1M context) noreply@anthropic.com

  Downloads

  • Source Code (ZIP)
  • Source Code (TAR.GZ)