From 0b46d00bb2788e8222e249c48147d72ba94811a1 Mon Sep 17 00:00:00 2001
From: George Stykalin <gstykalin@mail.ru>
Date: Wed, 15 Apr 2026 12:04:00 +0300
Subject: [PATCH] update dags

---
 dags/test-train-pytorch.py | 85 ++++++++------------------------------
 dags/train.py              | 35 ++++++++++++++++
 2 files changed, 53 insertions(+), 67 deletions(-)
 create mode 100644 dags/train.py

diff --git a/dags/test-train-pytorch.py b/dags/test-train-pytorch.py
index 8f2e16f..607df4b 100644
--- a/dags/test-train-pytorch.py
+++ b/dags/test-train-pytorch.py
@@ -1,12 +1,26 @@
 from airflow import DAG
 from airflow.operators.python import PythonOperator
 import pendulum
+import subprocess
 from datetime import timedelta
 
 
 WORLD_SIZE = 2
-MASTER_ADDR = "127.0.0.1"
-MASTER_PORT = "29500"
+
+
+def run_ddp_job():
+    cmd = [
+        "torchrun",
+        "--nproc_per_node=2",
+        "--standalone",
+        "train.py"
+    ]
+
+    print("Running:", " ".join(cmd))
+
+    subprocess.run(cmd, check=True)
+
+    return {"status": "success"}
 
 
 default_args = {
@@ -16,77 +30,14 @@ default_args = {
 }
 
 
-# =========================
-# SINGLE SAFE DDP LAUNCHER
-# =========================
-def run_ddp_job():
-    import os
-    import torch
-    import torch.distributed as dist
-    import torch.multiprocessing as mp
-    import torch.nn as nn
-    import torch.optim as optim
-
-    def worker(rank, world_size):
-        os.environ["MASTER_ADDR"] = MASTER_ADDR
-        os.environ["MASTER_PORT"] = MASTER_PORT
-        os.environ["WORLD_SIZE"] = str(world_size)
-        os.environ["RANK"] = str(rank)
-
-        # optional debug
-        os.environ["NCCL_DEBUG"] = "INFO"
-        os.environ["NCCL_ASYNC_ERROR_HANDLING"] = "1"
-
-        torch.cuda.set_device(0)
-
-        dist.init_process_group(
-            backend="nccl",
-            init_method="env://",
-            rank=rank,
-            world_size=world_size,
-        )
-
-        model = nn.Linear(10, 10).cuda()
-
-        ddp_model = torch.nn.parallel.DistributedDataParallel(
-            model,
-            device_ids=[0]
-        )
-
-        loss_fn = nn.MSELoss()
-        opt = optim.SGD(ddp_model.parameters(), lr=0.01)
-
-        for epoch in range(5):
-            x = torch.randn(32, 10).cuda()
-            y = torch.randn(32, 10).cuda()
-
-            opt.zero_grad()
-            out = ddp_model(x)
-            loss = loss_fn(out, y)
-            loss.backward()
-            opt.step()
-
-            print(f"rank {rank} epoch {epoch} loss {loss.item()}")
-
-        dist.destroy_process_group()
-
-    # IMPORTANT: THIS FIXES NCCL HANG
-    mp.spawn(worker, args=(WORLD_SIZE,), nprocs=WORLD_SIZE, join=True)
-
-    return {"status": "success"}
-
-
-# =========================
-# AIRFLOW DAG
-# =========================
 with DAG(
-    dag_id="pytorch_ddp_airflow_fixed_stable",
+    dag_id="pytorch_ddp_airflow_fixed_production",
     default_args=default_args,
     schedule=None,
     start_date=pendulum.today("UTC").add(days=-1),
     catchup=False,
     max_active_runs=1,
-    tags=["ddp", "gpu", "stable"],
+    tags=["ddp", "torchrun", "stable"],
 ) as dag:
 
     train = PythonOperator(
diff --git a/dags/train.py b/dags/train.py
new file mode 100644
index 0000000..5f898a0
--- /dev/null
+++ b/dags/train.py
@@ -0,0 +1,35 @@
+import torch
+import torch.distributed as dist
+import torch.nn as nn
+import torch.optim as optim
+
+
+def main():
+    dist.init_process_group("nccl")
+
+    rank = dist.get_rank()
+    torch.cuda.set_device(0)
+
+    model = nn.Linear(10, 10).cuda()
+    ddp = torch.nn.parallel.DistributedDataParallel(model, device_ids=[0])
+
+    opt = optim.SGD(ddp.parameters(), lr=0.01)
+    loss_fn = nn.MSELoss()
+
+    for i in range(5):
+        x = torch.randn(32, 10).cuda()
+        y = torch.randn(32, 10).cuda()
+
+        opt.zero_grad()
+        out = ddp(x)
+        loss = loss_fn(out, y)
+        loss.backward()
+        opt.step()
+
+        print(f"rank {rank} step {i} loss {loss.item()}")
+
+    dist.destroy_process_group()
+
+
+if __name__ == "__main__":
+    main()