[https://nvbugs/5649010][fix] use 0 port as arbitrary port when disagg service discovery is enabled

tensorrt_llm/commands/serve.py

@@ -18,7 +18,7 @@
 from tensorrt_llm import LLM as PyTorchLLM
 from tensorrt_llm import MultimodalEncoder
 from tensorrt_llm._tensorrt_engine import LLM
-from tensorrt_llm._utils import mpi_rank
+from tensorrt_llm._utils import get_free_port, mpi_rank
 from tensorrt_llm.executor.utils import LlmLauncherEnvs
 from tensorrt_llm.inputs.multimodal import MultimodalServerConfig
 from tensorrt_llm.llmapi import (BuildConfig, CapacitySchedulerPolicy,
@@ -180,10 +180,27 @@ def launch_server(
     backend = llm_args["backend"]
     model = llm_args["model"]
     with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as s:
-        try:
-            s.bind((host, port))
-        except OSError as e:
-            raise RuntimeError(f"Failed to bind socket to {host}:{port}: {e}")
+        # If disagg cluster config is provided and port is not specified, try to find a free port, otherwise try to bind to the specified port
+        assert port > 0 or disagg_cluster_config is not None, "Port must be specified if disagg cluster config is not provided"
+        if port > 0:
+            port_retries = 1
+        else:
+            port_retries = 100
+            port = get_free_port()
+        while port_retries > 0:
+            try:
+                s.bind((host, port))
+                break
+            except OSError as e:
+                port_retries -= 1
+                if port_retries == 0:
+                    raise RuntimeError(
+                        f"Failed to bind socket to {host}:{port}: {e}")
+                else:
+                    logger.warning(
+                        f"Failed to bind socket to {host}:{port}: {e}, retrying {port_retries}..."
+                    )
+                port = get_free_port()
 
         if backend == 'pytorch':
             llm_args.pop("build_config", None)

tests/integration/defs/disaggregated/test_auto_scaling.py

@@ -23,24 +23,6 @@
 CHECK_STATUS_INTERVAL = 3
 
 ROUTER_TYPES = ["round_robin", "load_balancing", "kv_cache_aware"]
-USED_PORTS = set()
-
-
-# get_free_port doesn't guarantee that consecutive calls will return different ports
-# if no server is bound to the port immediately after the call
-def get_free_unused_port():
-    global USED_PORTS
-    max_attempts = 100
-    for _ in range(max_attempts):
-        port = get_free_port()
-        assert port > 0, f"get_free_port returned {port}"
-        if port not in USED_PORTS:
-            USED_PORTS.add(port)
-            return port
-        else:
-            logger.info(f"Port {port} is already used, trying another one")
-    raise Exception(
-        f"Failed to find a free unused port after {max_attempts} attempts")
 
 
 @pytest.fixture
@@ -53,7 +35,7 @@ def model_name():
 
 @pytest.fixture
 def disagg_port():
-    return get_free_unused_port()
+    return get_free_port()
 
 
 @pytest.fixture
@@ -145,8 +127,6 @@ def _run_worker(model_name,
                 work_dir,
                 device=-1,
                 save_log=False):
-    if port == 0:
-        port = get_free_unused_port()
     worker_config_path = os.path.join(work_dir, f"{role}_{port}_config.yaml")
     with open(worker_config_path, "w+") as f:
         yaml.dump(worker_config, f)
@@ -187,6 +167,7 @@ def _run_worker(model_name,
                               port=port)
 
 
+# Use 0 as the port and provide disagg_cluster_config to let the worker choose a free port
 def run_ctx_worker(model_name, ctx_worker_config, work_dir, port=0, device=0):
     return _run_worker(model_name, ctx_worker_config, "ctx", port, work_dir,
                        device)
@@ -246,19 +227,38 @@ async def wrapper(*args, **kwargs):
     return decorator
 
 
-@periodic_check(timeout=300, interval=3)
-async def wait_for_disagg_server_ready(port):
+async def _wait_for_disagg_server_status(port,
+                                         ready=True,
+                                         min_ctx_workers=-1,
+                                         min_gen_workers=-1):
     info_resp = requests.get(f"http://localhost:{port}/cluster_info")
     logger.info(
         f"Waiting for disagg server {port} to be ready: {info_resp.json()}")
     if info_resp.status_code == 200:
         info = info_resp.json()
-        return info["is_ready"]
-    else:
-        logger.info(f"Failed to get cluster info: {info_resp.status_code}")
+        if ready:
+            return info["is_ready"]
+        else:
+            return len(info["current_workers"]
+                       ["context_servers"]) >= min_ctx_workers and len(
+                           info["current_workers"]
+                           ["generation_servers"]) >= min_gen_workers
     return False
 
 
+@periodic_check(timeout=300, interval=3)
+async def wait_for_disagg_server_ready(port):
+    return await _wait_for_disagg_server_status(port, True)
+
+
+@periodic_check(timeout=300, interval=3)
+async def wait_for_disagg_server_status(port,
+                                        min_ctx_workers=-1,
+                                        min_gen_workers=-1):
+    return await _wait_for_disagg_server_status(port, False, min_ctx_workers,
+                                                min_gen_workers)
+
+
 @periodic_check(timeout=300, interval=3)
 async def wait_for_worker_ready(port):
     logger.info(f"Waiting for worker {port} to be ready")
@@ -314,9 +314,6 @@ def terminate(*args, show_log_lines=30, release_port=True):
                     if arg.log_file:
                         arg.log_file.close()
                         arg.log_file = None
-                    if release_port:
-                        global USED_PORTS
-                        USED_PORTS.discard(arg.port)
                 except Exception:
                     print(f"Failed to terminate process {arg.process.pid}")
             else:
@@ -399,8 +396,7 @@ async def test_minimal_instances(model_name, disagg_server_config,
         gen_worker1 = run_gen_worker(model_name, worker_config, work_dir)
         disagg_server = run_disagg_server(disagg_server_config, work_dir,
                                           disagg_port)
-        await wait_for_worker_ready(ctx_worker1.port)
-        await wait_for_worker_ready(gen_worker1.port)
+        await wait_for_disagg_server_status(disagg_port, 1, 1)
         verify_cluster_info(False, 1, 1, port=disagg_port)
         # with only 1 ctx and 1 gen worker, the request should fail
         with pytest.raises(Exception):
@@ -470,7 +466,7 @@ async def test_worker_restart(model_name, disagg_server_config, worker_config,
                                      work_dir,
                                      port=0,
                                      device=2)
-        await wait_for_worker_ready(gen_worker2.port)
+        await wait_for_disagg_server_status(disagg_port, 1, 1)
         await asyncio.sleep(CHECK_STATUS_INTERVAL)
         verify_cluster_info(True, 1, 1, port=disagg_port)
 
@@ -492,7 +488,8 @@ async def test_worker_restart(model_name, disagg_server_config, worker_config,
                                      work_dir,
                                      port=0,
                                      device=3)
-        await wait_for_worker_ready(ctx_worker2.port)
+        await wait_for_disagg_server_status(disagg_port, 1, 1)
+        await asyncio.sleep(CHECK_STATUS_INTERVAL)
         verify_cluster_info(True, 1, 1, port=disagg_port)
 
         response = request_completion(model_name, test_prompt, port=disagg_port)
@@ -510,8 +507,7 @@ async def test_worker_restart(model_name, disagg_server_config, worker_config,
                                      work_dir,
                                      port=0,
                                      device=1)
-        await wait_for_worker_ready(ctx_worker1.port)
-        await wait_for_worker_ready(gen_worker1.port)
+        await wait_for_disagg_server_status(disagg_port, 2, 2)
         await asyncio.sleep(CHECK_STATUS_INTERVAL)
         verify_cluster_info(True, 2, 2, port=disagg_port)