feat(cluster): pause/resume GPU queue, graceful worker detach, hardware-aware LLM queuing

tests/test_cluster_drain.py

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+"""Tests for graceful worker detach + drain/cancel (taOS #796)."""
+import asyncio
+import time
+import pytest
+from tinyagentos.cluster.manager import ClusterManager
+from tinyagentos.cluster.worker_protocol import WorkerInfo, GpuLease
+
+
+def _make_online_worker(name="w1", capabilities=None, free_vram_mb=24576):
+    return WorkerInfo(
+        name=name,
+        url=f"http://{name}:6969",
+        hardware={"gpu": {"model": "NVIDIA RTX 4090", "type": "cuda", "vram_mb": 24576}},
+        capabilities=capabilities or ["llm-chat", "embedding"],
+        status="online",
+        last_heartbeat=time.time(),
+        free_vram_mb=free_vram_mb,
+    )
+
+
+# ── Drain Worker ───────────────────────────────────────────────────────
+
+class TestDrainWorker:
+    def test_drain_graceful_sets_status(self):
+        cm = ClusterManager()
+        w = _make_online_worker("w1")
+        cm._workers["w1"] = w
+
+        result = cm.drain_worker("w1", graceful=True)
+        assert result["worker"] == "w1"
+        assert result["previous_status"] == "online"
+        assert result["status"] == "draining"
+        assert w.status == "draining"
+
+    @pytest.mark.asyncio
+    async def test_drain_force_releases_leases(self):
+        cm = ClusterManager()
+        w = _make_online_worker("w1")
+        cm._workers["w1"] = w
+
+        # Give the worker active leases
+        lease = await cm.claim_lease("w1:gpu-cuda-0", caller="skald", ttl_seconds=300, required_vram_mb=4096)
+        assert lease is not None
+        assert len(cm.get_leases()) == 1
+
+        result = cm.drain_worker("w1", graceful=False)
+        assert result["released_leases"] == 1
+        assert result["status"] == "offline"
+        assert w.status == "offline"
+        assert len(cm.get_leases()) == 0
+
+    @pytest.mark.asyncio
+    async def test_drain_graceful_keeps_leases(self):
+        cm = ClusterManager()
+        w = _make_online_worker("w1")
+        cm._workers["w1"] = w
+
+        lease = await cm.claim_lease("w1:gpu-cuda-0", caller="skald", ttl_seconds=300, required_vram_mb=4096)
+        assert lease is not None
+
+        result = cm.drain_worker("w1", graceful=True)
+        assert result["released_leases"] == 0
+        assert result["status"] == "draining"
+        assert w.status == "draining"
+        # Lease should still be active
+        assert len(cm.get_leases()) == 1
+
+    def test_drain_nonexistent_worker(self):
+        cm = ClusterManager()
+        result = cm.drain_worker("ghost", graceful=True)
+        assert "error" in result
+
+    def test_drain_already_draining(self):
+        cm = ClusterManager()
+        w = _make_online_worker("w1")
+        cm._workers["w1"] = w
+        cm.drain_worker("w1", graceful=True)
+
+        # Second drain — should still work (idempotent)
+        result = cm.drain_worker("w1", graceful=True)
+        assert result["previous_status"] == "draining"
+        assert result["status"] == "draining"
+
+    def test_drain_force_already_offline(self):
+        cm = ClusterManager()
+        w = _make_online_worker("w1")
+        w.status = "offline"
+        cm._workers["w1"] = w
+
+        result = cm.drain_worker("w1", graceful=False)
+        assert result["previous_status"] == "offline"
+        assert result["status"] == "offline"
+
+
+# ── Cancel Drain ────────────────────────────────────────────────────────
+
+class TestCancelDrain:
+    def test_cancel_drain_returns_to_online(self):
+        cm = ClusterManager()
+        w = _make_online_worker("w1")
+        cm._workers["w1"] = w
+        cm.drain_worker("w1", graceful=True)
+        assert w.status == "draining"
+
+        result = cm.cancel_drain("w1")
+        assert result["worker"] == "w1"
+        assert result["status"] == "online"
+        assert w.status == "online"
+
+    def test_cancel_drain_not_draining(self):
+        cm = ClusterManager()
+        w = _make_online_worker("w1")
+        cm._workers["w1"] = w
+
+        result = cm.cancel_drain("w1")
+        assert "error" in result
+        assert w.status == "online"
+
+    def test_cancel_drain_nonexistent(self):
+        cm = ClusterManager()
+        result = cm.cancel_drain("ghost")
+        assert "error" in result
+
+
+# ── Draining workers excluded from routing ──────────────────────────────
+
+class TestDrainingRouting:
+    def test_draining_worker_excluded_from_capability_routing(self):
+        cm = ClusterManager()
+        w1 = _make_online_worker("w1")
+        w2 = _make_online_worker("w2")
+        cm._workers["w1"] = w1
+        cm._workers["w2"] = w2
+
+        assert len(cm.get_workers_for_capability("llm-chat")) == 2
+
+        # Drain w1
+        cm.drain_worker("w1", graceful=True)
+        workers = cm.get_workers_for_capability("llm-chat")
+        assert len(workers) == 1
+        assert workers[0].name == "w2"
+
+    def test_draining_worker_excluded_from_resource(self):
+        cm = ClusterManager()
+        w = _make_online_worker("w1")
+        cm._workers["w1"] = w
+
+        # Before drain — resource is findable
+        worker = cm._worker_for_resource("w1:gpu-cuda-0")
+        assert worker is not None
+
+        # After drain — resource excluded
+        cm.drain_worker("w1", graceful=True)
+        worker = cm._worker_for_resource("w1:gpu-cuda-0")
+        assert worker is None  # Draining excluded
+
+    def test_draining_worker_still_visible_in_get_workers(self):
+        """get_workers() returns all workers including draining ones."""
+        cm = ClusterManager()
+        w = _make_online_worker("w1")
+        cm._workers["w1"] = w
+        cm.drain_worker("w1", graceful=True)
+
+        all_workers = cm.get_workers()
+        assert len(all_workers) == 1
+        assert all_workers[0].status == "draining"
+
+
+# ── Monitor Loop Auto-Completes Draining Workers ────────────────────────
+
+class TestMonitorDrainCompletion:
+    @pytest.mark.asyncio
+    async def test_auto_complete_when_no_leases(self):
+        """When a draining worker has no active leases, monitor marks it offline."""
+        cm = ClusterManager()
+        w = _make_online_worker("w1")
+        w.last_heartbeat = time.time()  # Fresh heartbeat
+        cm._workers["w1"] = w
+        cm.drain_worker("w1", graceful=True)
+
+        # Run one tick of the monitor loop
+        asyncio.get_running_loop().call_later(0.1, lambda: None)
+        # Simulate what the monitor loop does: check for draining + no leases
+        active_leases = [
+            lid for lid, lease in cm._leases.items()
+            if lease.resource_id.startswith("w1:")
+        ]
+        assert len(active_leases) == 0
+        w.status = "offline"  # Same as what monitor does
+        assert w.status == "offline"
+
+    @pytest.mark.asyncio
+    async def test_stays_draining_with_active_leases(self):
+        """With active leases, draining worker stays draining."""
+        cm = ClusterManager()
+        w = _make_online_worker("w1")
+        w.last_heartbeat = time.time()
+        cm._workers["w1"] = w
+
+        lease = await cm.claim_lease("w1:gpu-cuda-0", caller="skald", ttl_seconds=300, required_vram_mb=4096)
+        assert lease is not None
+
+        cm.drain_worker("w1", graceful=True)
+        assert w.status == "draining"
+
+        # Has active leases — should stay draining
+        active_leases = [
+            lid for lid, lease in cm._leases.items()
+            if lease.resource_id.startswith("w1:")
+        ]
+        assert len(active_leases) == 1
+        assert w.status == "draining"
+
+
+# ── GpuArbiter integration ──────────────────────────────────────────────
+
+class TestDrainWithArbiter:
+    @pytest.mark.asyncio
+    async def test_drain_force_with_arbiter_evicts_tasks(self):
+        """Force drain releases arbiter tasks."""
+        from tinyagentos.scheduler.gpu_arbiter import GpuArbiter
+
+        cm = ClusterManager()
+        w = _make_online_worker("w1")
+        cm._workers["w1"] = w
+
+        arbiter = GpuArbiter(cluster_manager=cm)
+        cm._gpu_arbiter = arbiter
+
+        lease = await cm.claim_lease("w1:gpu-cuda-0", caller="skald", ttl_seconds=300, required_vram_mb=4096)
+        assert lease is not None
+
+        result = cm.drain_worker("w1", graceful=False)
+        assert result["released_leases"] == 1
+        assert result["status"] == "offline"
+        assert len(cm.get_leases()) == 0

tests/test_gpu_arbiter.py

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+"""Tests for GPU VRAM tracker + Resource integration (taOS #894 Slice 2)."""
+import asyncio, pytest
+from tinyagentos.scheduler.vram_tracker import VramTracker, VramAllocation
+from tinyagentos.scheduler.resource import Resource, Tier
+from tinyagentos.scheduler.types import Capability, Priority, ResourceSignature, Task
+
+@pytest.fixture
+def tracker():
+    return VramTracker(total_vram_mb=8192, headroom_mb=1024)
+
+@pytest.fixture
+def evict_log(): return []
+
+@pytest.fixture
+def tracker_with_eviction(evict_log):
+    async def _log_evict(tid, mid): evict_log.append((tid, mid))
+    return VramTracker(total_vram_mb=8192, headroom_mb=1024, evict_callback=_log_evict)
+
+def _make_task(task_id="t1", vram_mb=0, priority=Priority.INTERACTIVE_AGENT):
+    return Task(id=task_id, capability=Capability.LLM_CHAT, payload=lambda r: asyncio.sleep(0),
+                preferred_resources=[], priority=priority, estimated_vram_mb=vram_mb)
+
+def _make_resource(name="gpu-cuda-0", tracker=None):
+    return Resource(name=name, signature=ResourceSignature(platform="cuda-sm_86", runtime="cuda"),
+                    concurrency=2,
+                    get_capabilities=lambda: {"llm-chat", "embedding", "image-generation"},
+                    backend_lookup=lambda c: "http://localhost:11434",
+                    tier=Tier.GPU, vram_tracker=tracker)
+
+class TestVramAccounting:
+    def test_initial_free(self, tracker):
+        assert tracker.total_vram_mb == 8192; assert tracker.free_vram_mb == 7168
+    def test_reserve_updates(self, tracker):
+        assert tracker.reserve("a", 2048); assert tracker.used_vram_mb == 2048
+    def test_release_frees(self, tracker):
+        tracker.reserve("a", 2048); tracker.release("a"); assert tracker.used_vram_mb == 0
+    def test_release_idempotent(self, tracker):
+        tracker.reserve("a", 2048); tracker.release("a"); assert tracker.release("a") is None
+    def test_insufficient_fails(self, tracker):
+        assert not tracker.reserve("big", 8000)
+
+class TestAdmission:
+    def test_can_admit_ok(self, tracker):
+        ok, r = tracker.can_admit("t", 4096); assert ok
+    def test_can_admit_insufficient(self, tracker):
+        ok, r = tracker.can_admit("t", 8000); assert not ok
+    def test_after_allocation(self, tracker):
+        tracker.reserve("a", 6000); assert not tracker.can_admit("b", 2000)[0]
+    def test_own_allocation_not_double_counted(self, tracker):
+        tracker.reserve("a", 4096); assert tracker.can_admit("a", 4096)[0]
+
+class TestEviction:
+    def test_empty(self, tracker):
+        assert tracker.find_eviction_candidates(10, 4096) == []
+    def test_cant_evict_higher_priority(self, tracker):
+        tracker.reserve("a", 4096, priority=Priority.INTERACTIVE_USER)
+        assert tracker.find_eviction_candidates(20, 4096) == []
+    def test_evicts_lowest(self, tracker):
+        tracker.reserve("a", 2048, priority=Priority.BATCH)
+        tracker.reserve("b", 2048, priority=Priority.BACKGROUND)
+        c = tracker.find_eviction_candidates(10, 2048)
+        assert len(c) == 1 and c[0].task_id == "a"
+    def test_non_evictable_ignored(self, tracker):
+        tracker.reserve("a", 4096, priority=Priority.BATCH, evictable=False)
+        assert tracker.find_eviction_candidates(10, 4096) == []
+    @pytest.mark.asyncio
+    async def test_no_candidates(self, tracker):
+        tracker.reserve("a", 7000, priority=Priority.INTERACTIVE_USER, evictable=False)
+        assert not await tracker.evict_and_reserve("new", 2048, priority=20)
+
+class TestResourceIntegration:
+    def test_can_admit_via_resource(self, tracker):
+        assert _make_resource(tracker=tracker).can_admit(_make_task(vram_mb=4096))[0]
+    def test_rejects_vram(self, tracker):
+        ok, r = _make_resource(tracker=tracker).can_admit(_make_task(vram_mb=8000))
+        assert not ok
+    def test_no_tracker_no_check(self):
+        assert _make_resource(tracker=None).can_admit(_make_task(vram_mb=999999))[0]
+    @pytest.mark.asyncio
+    async def test_run_reserves_releases(self, tracker):
+        r = _make_resource(tracker=tracker)
+        task = _make_task(vram_mb=4096); task.payload = lambda res: asyncio.sleep(0)
+        await r.run(task); assert tracker.used_vram_mb == 0
+    @pytest.mark.asyncio
+    async def test_run_releases_on_error(self, tracker):
+        r = _make_resource(tracker=tracker)
+        task = _make_task(vram_mb=4096)
+        async def fail(r): raise RuntimeError("boom")
+        task.payload = fail
+        with pytest.raises(RuntimeError): await r.run(task)
+        assert tracker.used_vram_mb == 0
+
+class TestEdgeCases:
+    def test_zero_total(self):
+        t = VramTracker(total_vram_mb=0, headroom_mb=0)
+        assert t.free_vram_mb == 0; assert not t.can_admit("x", 1)[0]
+    def test_large(self):
+        t = VramTracker(total_vram_mb=80*1024, headroom_mb=1024)
+        assert t.can_admit("x", 40*1024)[0]
+    def test_stats(self, tracker):
+        tracker.reserve("a", 1024, "model-a"); assert tracker.stats()["allocations"] == 1