dist.ddp: make rendezvous work out of the box on all schedulers

Author: d4l3k

scripts/awsbatchint.sh

@@ -7,7 +7,28 @@
 
 set -ex
 
-RUN_ARGS="--scheduler aws_batch -c queue=torchx,image_repo=495572122715.dkr.ecr.us-west-2.amazonaws.com/torchx/integration-tests utils.echo"
+JOB="$USER-$(uuidgen)"
+DIR="/tmp/$JOB"
+
+function cleanup {
+  rm  -r "$DIR"
+}
+trap cleanup EXIT
+
+mkdir "$DIR"
+cd "$DIR"
+
+cat <<EOT > .torchxconfig
+[aws_batch]
+queue=torchx
+image_repo=495572122715.dkr.ecr.us-west-2.amazonaws.com/torchx/integration-tests
+EOT
+
+cat <<EOT > main.py
+print("hello world!")
+EOT
+
+RUN_ARGS="--scheduler aws_batch dist.ddp -j 2x1 --script main.py"
 
 if [ -z "$AWS_ROLE_ARN" ]; then
   # only dryrun if no secrets
@@ -21,9 +42,9 @@ else
   torchx log "$APP_ID"
   LINES="$(torchx log "$APP_ID" | wc -l)"
 
-  if [ "$LINES" -ne 1 ]
+  if [ "$LINES" -ne 2 ]
   then
-      echo "expected 1 log lines"
+      echo "expected 2 log lines"
       exit 1
   fi
 fi

scripts/slurmint.sh

@@ -20,7 +20,7 @@ if [[ -z "${SLURM_INSTANCE_MASTER}" ]]; then
 fi
 
 JOB="$USER-$(uuidgen)"
-DIR="/tmp/$JOB"
+DIR="/home/ubuntu/integ-tests/$JOB"
 VENV="$DIR/venv"
 
 function run_cmd {
@@ -44,8 +44,8 @@ REMOTE_WHEEL="$DIR/$(basename "$WHEEL")"
 SCRIPT="scripts/slurmtest.sh"
 REMOTE_SCRIPT="$DIR/$(basename "$SCRIPT")"
 
-run_cmd mkdir "$DIR"
-run_cmd virtualenv -p /usr/bin/python3.8 "$VENV"
+run_cmd mkdir -p "$DIR"
+run_cmd virtualenv -p /home/ubuntu/miniconda3/bin/python "$VENV"
 run_scp "$WHEEL" "$REMOTE_WHEEL"
 run_scp "$SCRIPT" "$REMOTE_SCRIPT"
 run_cmd "$REMOTE_SCRIPT" "$REMOTE_WHEEL" "$VENV"

scripts/slurmtest.sh

@@ -10,23 +10,43 @@ set -ex
 REMOTE_WHEEL="$1"
 VENV="$2"
 
+BASE_DIR="$(dirname "$REMOTE_WHEEL")"
+DIR="$BASE_DIR/project"
+mkdir "$DIR"
+cd "$DIR"
+
 # shellcheck disable=SC1091
 source /opt/slurm/etc/slurm.sh
 sbatch --version
 # shellcheck disable=SC1090
 source "$VENV"/bin/activate
 python --version
+
 pip install "$REMOTE_WHEEL"
+pip install numpy
+pip install torch==1.10.2+cpu -f https://download.pytorch.org/whl/cpu/torch_stable.html
+
+cat <<EOT > .torchxconfig
+[slurm]
+partition=compute
+time=10
+comment=hello
+nomem=true
+EOT
+
+cat <<EOT > main.py
+print("hello world!")
+EOT
 
-APP_ID="$(torchx run --wait --scheduler slurm --scheduler_args partition=compute,time=10,comment=hello utils.echo --num_replicas 3)"
+APP_ID="$(torchx run --wait --log --scheduler slurm dist.ddp -j 2x1 --script main.py)"
 torchx status "$APP_ID"
 torchx describe "$APP_ID"
 sacct -j "$(basename "$APP_ID")"
 torchx log "$APP_ID"
-LINES="$(torchx log "$APP_ID" | wc -l)"
+LINES="$(torchx log "$APP_ID" | grep 'hello world' | wc -l)"
 
-if [ "$LINES" -ne 3 ]
+if [ "$LINES" -ne 2 ]
 then
-    echo "expected 3 log lines"
+    echo "expected 2 log lines"
     exit 1
 fi

torchx/components/dist.py

@@ -121,8 +121,9 @@
 Components APIs
 -----------------
 """
+import shlex
 from pathlib import Path
-from typing import Dict, Optional
+from typing import Dict, Optional, Iterable
 
 import torchx
 import torchx.specs as specs
@@ -140,7 +141,8 @@ def ddp(
     h: Optional[str] = None,
     j: str = "1x2",
     env: Optional[Dict[str, str]] = None,
-    rdzv_endpoint: str = "etcd-server.default.svc.cluster.local:2379",
+    rdzv_backend: str = "c10d",
+    rdzv_endpoint: Optional[str] = None,
 ) -> specs.AppDef:
     """
     Distributed data parallel style application (one role, multi-replica).
@@ -162,7 +164,8 @@ def ddp(
         h: a registered named resource (if specified takes precedence over cpu, gpu, memMB)
         j: {nnodes}x{nproc_per_node}, for gpu hosts, nproc_per_node must not exceed num gpus
         env: environment varibles to be passed to the run (e.g. ENV1=v1,ENV2=v2,ENV3=v3)
-        rdzv_endpoint: etcd server endpoint (only matters when nnodes > 1)
+        rdzv_backend: rendezvous backend (only matters when nnodes > 1)
+        rdzv_endpoint: rendezvous server endpoint (only matters when nnodes > 1), defaults to rank0 host for schedulers that support it
     """
 
     rep = j.split("x")
@@ -176,32 +179,63 @@ def ddp(
         raise ValueError(f"Invalid format for -j, usage example: 1x4. Given: {j}")
 
     script_name_noext = Path(script).stem  # script name no extension
+
+    if rdzv_endpoint is None:
+        rdzv_endpoint = _noquote(f"$${macros.rank0_env}:29500")
+
+    if nnodes == 1:
+        rdzv_backend = "c10d"
+        rdzv_endpoint = "localhost:29500"
+
+    cmd = [
+        "python",
+        "-m",
+        "torch.distributed.run",
+        "--rdzv_backend",
+        rdzv_backend,
+        "--rdzv_endpoint",
+        rdzv_endpoint,
+        "--rdzv_id",
+        f"{macros.app_id}",
+        "--nnodes",
+        str(nnodes),
+        "--nproc_per_node",
+        str(nproc_per_node),
+        script,
+        *script_args,
+    ]
     return specs.AppDef(
         name=name or script_name_noext,
         roles=[
             specs.Role(
                 name=script_name_noext,
                 image=image,
-                entrypoint="python",
+                entrypoint="bash",
                 num_replicas=nnodes,
                 resource=specs.resource(cpu=cpu, gpu=gpu, memMB=memMB, h=h),
-                args=[
-                    "-m",
-                    "torch.distributed.run",
-                    "--rdzv_backend",
-                    ("c10d" if nnodes == 1 else "etcd"),
-                    "--rdzv_endpoint",
-                    ("localhost:29500" if nnodes == 1 else rdzv_endpoint),
-                    "--rdzv_id",
-                    f"{macros.app_id}",
-                    "--nnodes",
-                    str(nnodes),
-                    "--nproc_per_node",
-                    str(nproc_per_node),
-                    script,
-                    *script_args,
-                ],
+                args=["-c", _args_join(cmd)],
                 env=env or {},
+                port_map={
+                    "c10d": 29500,
+                },
             )
         ],
     )
+
+
+def _args_join(args: Iterable[str]) -> str:
+    """
+    _args_join is like shlex.join but if the argument is wrapped in _noquote
+    it'll not quote that argument.
+    """
+    quoted = [arg if isinstance(arg, _noquote) else shlex.quote(arg) for arg in args]
+    return " ".join(quoted)
+
+
+class _noquote(str):
+    """
+    _noquote is a wrapper around str that indicates that the argument shouldn't
+    be passed through shlex.quote.
+    """
+
+    pass

torchx/components/integration_tests/component_provider.py

@@ -36,12 +36,11 @@ def tearDown(self) -> None:
 
 class DDPComponentProvider(ComponentProvider):
     def get_app_def(self) -> AppDef:
-        rdzv_endpoint: str = "localhost:29400"
         return dist_components.ddp(
             script="torchx/components/integration_tests/test/dummy_app.py",
             name="ddp-trainer",
             image=self._image,
-            rdzv_endpoint=rdzv_endpoint,
+            j="2x2",
         )
 
 

torchx/schedulers/api.py

@@ -24,6 +24,7 @@
     SchedulerBackend,
     runopts,
 )
+from torchx.workspace.api import Workspace
 
 
 class Stream(str, Enum):
@@ -90,13 +91,25 @@ def close(self) -> None:
         """
         pass
 
-    def submit(self, app: AppDef, cfg: Mapping[str, CfgVal]) -> str:
+    def submit(
+        self,
+        app: AppDef,
+        cfg: Mapping[str, CfgVal],
+        workspace: Optional[str] = None,
+    ) -> str:
         """
         Submits the application to be run by the scheduler.
 
+        WARNING: Mostly used for tests. Users should prefer to use the TorchX runner instead.
+
         Returns:
             The application id that uniquely identifies the submitted app.
         """
+        if workspace:
+            sched = self
+            assert isinstance(sched, Workspace)
+            role = app.roles[0]
+            sched.build_workspace_and_update_role(role, workspace)
         dryrun_info = self.submit_dryrun(app, cfg)
         return self.schedule(dryrun_info)
 

torchx/schedulers/aws_batch_scheduler.py

@@ -223,16 +223,28 @@ def _submit_dryrun(
 
         for role_idx, role in enumerate(app.roles):
             for replica_id in range(role.num_replicas):
+                rank = len(nodes)
                 values = macros.Values(
                     img_root="",
                     app_id=name,
                     replica_id=str(replica_id),
+                    rank0_env=(
+                        "TORCHX_RANK0_HOST"
+                        if rank == 0
+                        else "AWS_BATCH_JOB_MAIN_NODE_PRIVATE_IPV4_ADDRESS"
+                    ),
                 )
                 replica_role = values.apply(role)
                 replica_role.env["TORCHX_ROLE_IDX"] = str(role_idx)
                 replica_role.env["TORCHX_ROLE_NAME"] = str(role.name)
                 replica_role.env["TORCHX_REPLICA_IDX"] = str(replica_id)
-                nodes.append(role_to_node_properties(len(nodes), replica_role))
+                if rank == 0:
+                    # AWS_BATCH_JOB_MAIN_NODE_PRIVATE_IPV4_ADDRESS is only
+                    # available on the child workers so we set the address to
+                    # localhost for rank0.
+                    # See: https://docs.aws.amazon.com/batch/latest/userguide/job_env_vars.html
+                    replica_role.env["TORCHX_RANK0_HOST"] = "localhost"
+                nodes.append(role_to_node_properties(rank, replica_role))
 
         req = BatchJob(
             name=name,

torchx/schedulers/docker_scheduler.py

@@ -185,12 +185,14 @@ def _submit_dryrun(
 
         app_id = make_unique(app.name)
         req = DockerJob(app_id=app_id, containers=[])
+        rank0_name = f"{app_id}-{app.roles[0].name}-0"
         for role in app.roles:
             for replica_id in range(role.num_replicas):
                 values = macros.Values(
                     img_root="",
                     app_id=app_id,
                     replica_id=str(replica_id),
+                    rank0_env="TORCHX_RANK0_HOST",
                 )
                 replica_role = values.apply(role)
                 name = f"{app_id}-{role.name}-{replica_id}"
@@ -199,6 +201,9 @@ def _submit_dryrun(
                 if replica_role.env:
                     env.update(replica_role.env)
 
+                # configure distributed host envs
+                env["TORCHX_RANK0_HOST"] = rank0_name
+
                 c = DockerContainer(
                     image=replica_role.image,
                     command=[replica_role.entrypoint] + replica_role.args,

torchx/schedulers/kubernetes_scheduler.py

@@ -254,9 +254,14 @@ def app_to_resource(app: AppDef, queue: str) -> Dict[str, object]:
                 img_root="",
                 app_id=unique_app_id,
                 replica_id=str(replica_id),
+                rank0_env=f"VC_{app.roles[0].name}_0_HOSTS".upper(),
             )
+            if role_idx == 0 and replica_id == 0:
+                values.rank0_env = "TORCHX_RANK0_HOST"
             name = cleanup_str(f"{role.name}-{replica_id}")
             replica_role = values.apply(role)
+            if role_idx == 0 and replica_id == 0:
+                replica_role.env["TORCHX_RANK0_HOST"] = "localhost"
 
             pod = role_to_pod(name, replica_role)
             pod.metadata.labels.update(pod_labels(app, role_idx, role, replica_id))

torchx/schedulers/local_scheduler.py

@@ -864,8 +864,10 @@ def _to_popen_request(
                     img_root=img_root,
                     app_id=app_id,
                     replica_id=str(replica_id),
+                    rank0_env="TORCHX_RANK0_HOST",
                 )
                 replica_role = values.apply(role)
+                replica_role.env["TORCHX_RANK0_HOST"] = "localhost"
 
                 replica_log_dir = os.path.join(app_log_dir, role.name, str(replica_id))
                 if "TORCHELASTIC_ERROR_FILE" not in replica_role.env: