r4victor · Sep 25, 2024 · Sep 24, 2024 · Sep 25, 2024 · Sep 25, 2024 · Sep 25, 2024
diff --git a/docs/docs/concepts/fleets.md b/docs/docs/concepts/fleets.md
@@ -49,8 +49,10 @@ are both acceptable).
     to the specified parameters.
 
     !!! info "Network"
-        Set `placement` to `cluster` if the nodes should be interconnected (e.g. if you'd like to use them for multi-node tasks). 
-        In that case, `dstack` will provision all nodes in the same backend and region.
+        Set `placement` to `cluster` if the nodes should be interconnected
+        (e.g. if you'd like to use them for [multi-node tasks](reference/dstack.yml/task.md#distributed-tasks)). 
+        In that case, `dstack` will provision all nodes in the same backend and region and configure the optimal
+        connectivity via availability zones, placement groups, etc.
 
     Note that cloud fleets aren't supported for the `kubernetes`, `vastai`, and `runpod` backends.
 
@@ -120,7 +122,8 @@ are both acceptable).
         ```
 
     !!! info "Network"
-        Set `placement` to `cluster` if the hosts are interconnected (e.g. if you'd like to use them for multi-node tasks).
+        Set `placement` to `cluster` if the hosts are interconnected
+        (e.g. if you'd like to use them for [multi-node tasks](reference/dstack.yml/task.md#distributed-tasks)).
         In that case, by default, `dstack` will automatically detect the private network. 
         You can specify the [`network`](../reference/dstack.yml/fleet.md#network) parameter manually.
 

diff --git a/src/dstack/_internal/core/backends/__init__.py b/src/dstack/_internal/core/backends/__init__.py
@@ -18,6 +18,9 @@
     BackendType.OCI,
     BackendType.TENSORDOCK,
 ]
+BACKENDS_WITH_PLACEMENT_GROUPS_SUPPORT = [
+    BackendType.AWS,
+]
 BACKENDS_WITH_GATEWAY_SUPPORT = [
     BackendType.AWS,
     BackendType.AZURE,

diff --git a/src/dstack/_internal/core/backends/aws/compute.py b/src/dstack/_internal/core/backends/aws/compute.py
@@ -16,7 +16,7 @@
     get_user_data,
 )
 from dstack._internal.core.backends.base.offers import get_catalog_offers
-from dstack._internal.core.errors import ComputeError, NoCapacityError
+from dstack._internal.core.errors import ComputeError, NoCapacityError, PlacementGroupInUseError
 from dstack._internal.core.models.backends.aws import AWSAccessKeyCreds
 from dstack._internal.core.models.backends.base import BackendType
 from dstack._internal.core.models.common import CoreModel, is_core_model_instance
@@ -31,6 +31,7 @@
     InstanceOfferWithAvailability,
     SSHKey,
 )
+from dstack._internal.core.models.placement import PlacementGroup, PlacementGroupProvisioningData
 from dstack._internal.core.models.resources import Memory, Range
 from dstack._internal.core.models.runs import Job, JobProvisioningData, Requirements, Run
 from dstack._internal.core.models.volumes import (
@@ -116,7 +117,7 @@ def terminate_instance(
             ec2_client.terminate_instances(InstanceIds=[instance_id])
         except botocore.exceptions.ClientError as e:
             if e.response["Error"]["Code"] == "InvalidInstanceID.NotFound":
-                pass
+                logger.debug("Skipping instance %s termination. Instance not found.", instance_id)
             else:
                 raise e
 
@@ -181,6 +182,7 @@ def create_instance(
                         spot=instance_offer.instance.resources.spot,
                         subnet_id=subnet_id,
                         allocate_public_ip=allocate_public_ip,
+                        placement_group_name=instance_config.placement_group_name,
                     )
                 )
                 instance = response[0]
@@ -239,6 +241,41 @@ def run_job(
                 instance_config.availability_zone = volume.provisioning_data.availability_zone
         return self.create_instance(instance_offer, instance_config)
 
+    def create_placement_group(
+        self,
+        placement_group: PlacementGroup,
+    ) -> PlacementGroupProvisioningData:
+        ec2_client = self.session.client("ec2", region_name=placement_group.configuration.region)
+        logger.debug("Creating placement group %s...", placement_group.name)
+        ec2_client.create_placement_group(
+            GroupName=placement_group.name,
+            Strategy=placement_group.configuration.placement_strategy.value,
+        )
+        logger.debug("Created placement group %s", placement_group.name)
+        return PlacementGroupProvisioningData(
+            backend=BackendType.AWS,
+            backend_data=None,
+        )
+
+    def delete_placement_group(
+        self,
+        placement_group: PlacementGroup,
+    ):
+        ec2_client = self.session.client("ec2", region_name=placement_group.configuration.region)
+        logger.debug("Deleting placement group %s...", placement_group.name)
+        try:
+            ec2_client.delete_placement_group(GroupName=placement_group.name)
+        except botocore.exceptions.ClientError as e:
+            if e.response["Error"]["Code"] == "InvalidPlacementGroup.Unknown":
+                logger.debug("Placement group %s not found", placement_group.name)
+                return
+            elif e.response["Error"]["Code"] == "InvalidPlacementGroup.InUse":
+                logger.debug("Placement group %s is in use", placement_group.name)
+                raise PlacementGroupInUseError()
+            else:
+                raise e
+        logger.debug("Deleted placement group %s", placement_group.name)
+
     def create_gateway(
         self,
         configuration: GatewayComputeConfiguration,
@@ -372,7 +409,7 @@ def create_gateway(
 
     def terminate_gateway(
         self,
-        instance_id,
+        instance_id: str,
         configuration: GatewayComputeConfiguration,
         backend_data: Optional[str] = None,
     ):

diff --git a/src/dstack/_internal/core/backends/aws/resources.py b/src/dstack/_internal/core/backends/aws/resources.py
@@ -105,8 +105,9 @@ def create_instances_struct(
     spot: bool,
     subnet_id: Optional[str] = None,
     allocate_public_ip: bool = True,
+    placement_group_name: Optional[str] = None,
 ) -> Dict[str, Any]:
-    struct = dict(
+    struct: Dict[str, Any] = dict(
         BlockDeviceMappings=[
             {
                 "DeviceName": "/dev/sda1",
@@ -151,6 +152,12 @@ def create_instances_struct(
         ]
     else:
         struct["SecurityGroupIds"] = [security_group_id]
+
+    if placement_group_name is not None:
+        struct["Placement"] = {
+            "GroupName": placement_group_name,
+        }
+
     return struct
 
 

diff --git a/src/dstack/_internal/core/backends/base/compute.py b/src/dstack/_internal/core/backends/base/compute.py
@@ -17,6 +17,7 @@
     InstanceConfiguration,
     InstanceOfferWithAvailability,
 )
+from dstack._internal.core.models.placement import PlacementGroup, PlacementGroupProvisioningData
 from dstack._internal.core.models.runs import Job, JobProvisioningData, Requirements, Run
 from dstack._internal.core.models.volumes import (
     Volume,
@@ -62,8 +63,8 @@ def terminate_instance(
         backend_data: Optional[str] = None,
     ) -> None:
         """
-        Terminates an instance by `instance_id`. If instance does not exist,
-        it should not raise errors but return silently.
+        Terminates an instance by `instance_id`.
+        If the instance does not exist, it should not raise errors but return silently.
         """
         pass
 
@@ -95,6 +96,25 @@ def update_provisioning_data(
         """
         pass
 
+    def create_placement_group(
+        self,
+        placement_group: PlacementGroup,
+    ) -> PlacementGroupProvisioningData:
+        """
+        Creates a placement group.
+        """
+        raise NotImplementedError()
+
+    def delete_placement_group(
+        self,
+        placement_group: PlacementGroup,
+    ):
+        """
+        Deletes a placement group.
+        If the group does not exist, it should not raise errors but return silently.
+        """
+        raise NotImplementedError()
+
     def create_gateway(
         self,
         configuration: GatewayComputeConfiguration,

diff --git a/src/dstack/_internal/core/backends/remote/provisioning.py b/src/dstack/_internal/core/backends/remote/provisioning.py
@@ -7,6 +7,7 @@
 import paramiko
 from gpuhunt import correct_gpu_memory_gib
 
+# FIXME: ProvisioningError is a subclass of ComputeError and should not be used outside of Compute
 from dstack._internal.core.errors import ProvisioningError
 from dstack._internal.core.models.instances import (
     Disk,

diff --git a/src/dstack/_internal/core/errors.py b/src/dstack/_internal/core/errors.py
@@ -98,6 +98,10 @@ class ComputeResourceNotFoundError(ComputeError):
     pass
 
 
+class PlacementGroupInUseError(ComputeError):
+    pass
+
+
 class CLIError(DstackError):
     pass
 

diff --git a/src/dstack/_internal/core/models/instances.py b/src/dstack/_internal/core/models/instances.py
@@ -99,12 +99,13 @@ class DockerConfig(CoreModel):
 
 class InstanceConfiguration(CoreModel):
     project_name: str
-    instance_name: str  # unique in pool
-    instance_id: Optional[str] = None
-    ssh_keys: List[SSHKey]
-    job_docker_config: Optional[DockerConfig]
+    instance_name: str
     user: str  # dstack user name
+    ssh_keys: List[SSHKey]
+    instance_id: Optional[str] = None
     availability_zone: Optional[str] = None
+    placement_group_name: Optional[str] = None
+    job_docker_config: Optional[DockerConfig]  # FIXME: cannot find any usages – remove?
 
     def get_public_keys(self) -> List[str]:
         return [ssh_key.public.strip() for ssh_key in self.ssh_keys]

diff --git a/src/dstack/_internal/core/models/placement.py b/src/dstack/_internal/core/models/placement.py
@@ -0,0 +1,27 @@
+from enum import Enum
+from typing import Optional
+
+from dstack._internal.core.models.backends.base import BackendType
+from dstack._internal.core.models.common import CoreModel
+
+
+class PlacementStrategy(str, Enum):
+    CLUSTER = "cluster"
+
+
+class PlacementGroupConfiguration(CoreModel):
+    backend: BackendType
+    region: str
+    placement_strategy: PlacementStrategy
+
+
+class PlacementGroupProvisioningData(CoreModel):
+    backend: BackendType  # can be different from configuration backend
+    backend_data: Optional[str] = None
+
+
+class PlacementGroup(CoreModel):
+    name: str
+    project_name: str
+    configuration: PlacementGroupConfiguration
+    provisioning_data: Optional[PlacementGroupProvisioningData] = None
diff --git a/src/dstack/_internal/server/background/__init__.py b/src/dstack/_internal/server/background/__init__.py
@@ -9,6 +9,9 @@
 from dstack._internal.server.background.tasks.process_instances import (
     process_instances,
 )
+from dstack._internal.server.background.tasks.process_placement_groups import (
+    process_placement_groups,
+)
 from dstack._internal.server.background.tasks.process_running_jobs import process_running_jobs
 from dstack._internal.server.background.tasks.process_runs import process_runs
 from dstack._internal.server.background.tasks.process_submitted_jobs import process_submitted_jobs
@@ -45,5 +48,6 @@ def start_background_tasks() -> AsyncIOScheduler:
         process_submitted_volumes, IntervalTrigger(seconds=10, jitter=2), max_instances=5
     )
     _scheduler.add_job(process_fleets, IntervalTrigger(seconds=15))
+    _scheduler.add_job(process_placement_groups, IntervalTrigger(seconds=30))
     _scheduler.start()
     return _scheduler
diff --git a/src/dstack/_internal/server/background/tasks/process_fleets.py b/src/dstack/_internal/server/background/tasks/process_fleets.py
@@ -1,10 +1,10 @@
-from sqlalchemy import select
+from sqlalchemy import select, update
 from sqlalchemy.ext.asyncio import AsyncSession
 from sqlalchemy.orm import joinedload
 
 from dstack._internal.core.models.fleets import FleetStatus
 from dstack._internal.server.db import get_session_ctx
-from dstack._internal.server.models import FleetModel
+from dstack._internal.server.models import FleetModel, PlacementGroupModel
 from dstack._internal.server.services.fleets import (
     fleet_model_to_fleet,
     is_fleet_empty,
@@ -73,5 +73,16 @@ async def _autodelete_fleet(session: AsyncSession, fleet_model: FleetModel):
     fleet_model.status = FleetStatus.TERMINATED
     fleet_model.deleted = True
     fleet_model.last_processed_at = get_current_datetime()
+    await _mark_placement_groups_as_ready_for_deletion(session=session, fleet_model=fleet_model)
     await session.commit()
     logger.info("Fleet %s deleted", fleet_model.name)
+
+
+async def _mark_placement_groups_as_ready_for_deletion(
+    session: AsyncSession, fleet_model: FleetModel
+):
+    await session.execute(
+        update(PlacementGroupModel)
+        .where(PlacementGroupModel.fleet_id == fleet_model.id)
+        .values(fleet_deleted=True)
+    )
-Original file line number
+Diff line change
@@ Expand Up / @@ -98,6 +98,10 @@ class ComputeResourceNotFoundError(ComputeError): @@
         pass
+    class PlacementGroupInUseError(ComputeError):
+        pass
     class CLIError(DstackError):
         pass
@@ Expand Down @@