---
plan: 02-01
phase: 02-core-vm-lifecycle
status: complete
started: 2026-03-22T21:10:06Z
completed: 2026-03-22T21:15:00Z
commits:
  - 65aa81f
  - ba5fb7c
requirements-completed: []
---

# Plan 02-01: Thread-safe libvirt client abstraction layer

## What Was Built

`vmcluster_mcp/cluster/libvirt_client.py` — the complete libvirt abstraction layer that all Phase 2 cluster operations depend on. A single `ThreadPoolExecutor(max_workers=1)` serialises every libvirt C library call, satisfying D-08.

## Key Files

### Created
- `vmcluster_mcp/cluster/libvirt_client.py` — 145 lines, `LibvirtClient` class + 3 utility functions
- `tests/test_libvirt_client.py` — 31 unit tests, all passing with mocked libvirt

## Task Results

| Task | Status | Commit |
|------|--------|--------|
| Task 1: Create libvirt_client.py (TDD) | ✓ Complete | ba5fb7c |

### Commits
- `65aa81f` — test(02-01): add failing tests for LibvirtClient thread-safe wrapper (RED)
- `ba5fb7c` — feat(02-01): implement LibvirtClient thread-safe async libvirt wrapper (GREEN)

## Deviations from Plan

None — plan executed exactly as written.

## Self-Check
- [x] `vmcluster_mcp/cluster/libvirt_client.py` exists with `class LibvirtClient`
- [x] `ThreadPoolExecutor(max_workers=1)` present (exactly 1 worker, D-08)
- [x] `domain_name()`, `generate_mac()`, `map_domain_state()` utility functions present
- [x] `from __future__ import annotations` as first import
- [x] `logging.getLogger("vmcluster_mcp.cluster.libvirt_client")` present
- [x] `generate_mac()` returns `52:54:00:xx:xx:xx` deterministically
- [x] `map_domain_state(1) == "running"`, `map_domain_state(5) == "shut off"`
- [x] `LibvirtClient.__init__` does NOT call `libvirt.open` (lazy connection)
- [x] All async methods use `run_in_executor` (dispatched through `_run`)
- [x] `lookup_domain` and `lookup_network` return `None` on `libvirt.libvirtError`
- [x] `pytest tests/test_libvirt_client.py` → 31 passed
- [x] `ruff check vmcluster_mcp/cluster/libvirt_client.py` → All checks passed

## Self-Check: PASSED
