tf.contrib.cluster_resolver.SlurmClusterResolver

Class SlurmClusterResolver

Inherits From: ClusterResolver

Aliases:

  • Class tf.contrib.cluster_resolver.SlurmClusterResolver
  • Class tf.contrib.cluster_resolver.python.training.SlurmClusterResolver

Defined in tensorflow/python/distribute/cluster_resolver/slurm_cluster_resolver.py.

Cluster Resolver for system with Slurm workload manager.

This is an implementation of cluster resolvers for Slurm clusters. This allows the specification of jobs and task counts, number of tasks per node, number of GPUs on each node and number of GPUs for each task, It retrieves system attributes by Slurm environment variables, resolves allocated computing node names, construct a cluster and return a Cluster Resolver object which an be use for distributed TensorFlow.

__init__

__init__(
    jobs,
    port_base=8888,
    gpus_per_node=1,
    gpus_per_task=1,
    tasks_per_node=None,
    auto_set_gpu=True,
    rpc_layer='grpc'
)

Creates a new SlurmClusterResolver object.

This takes in parameters and creates a SlurmClusterResolver object. It uses those parameters to check which nodes will processes reside and resolves their hostnames. With the number of the GPUs on each node and number of GPUs for each task it offsets the port number for each processes and allocate GPUs to tasks by setting environment variables. The resolver currently supports homogeneous tasks and default Slurm process allocation.

Args:

  • jobs: Dictionary with job names as key and number of tasks in the job as value
  • port_base: The first port number to start with for processes on a node.
  • gpus_per_node: Number of GPUs available on each node.
  • gpus_per_task: Number of GPUs to be used for each task.
  • tasks_per_node: Number of tasks to run on each node, if not set defaults to Slurm's output environment variable SLURM_NTASKS_PER_NODE.
  • auto_set_gpu: Set the visible CUDA devices automatically while resolving the cluster by setting CUDA_VISIBLE_DEVICES environment variable. Defaults to True.
  • rpc_layer: (Optional) The protocol TensorFlow uses to communicate between nodes. Defaults to 'grpc'.

Returns:

A ClusterResolver object which can be used with distributed TensorFlow.

Raises:

  • RuntimeError: If requested more GPUs per node then available or requested more tasks then assigned tasks.

Properties

environment

Returns the current environment which TensorFlow is running in.

For users in the Slurm environment, the environment property is always an empty string, and Google users will not use this ClusterResolver for running on internal systems.

Methods

cluster_spec

cluster_spec()

Returns a ClusterSpec object based on the latest instance group info.

This returns a ClusterSpec object for use based on information from the specified initialization parameters and Slurm environment variables. The cluster specification is resolved each time this function is called. The resolver extract hostnames of nodes by scontrol and pack tasks in that order until a node a has number of tasks that is equal to specification. GPUs on nodes are allocated to tasks by specification through setting CUDA_VISIBLE_DEVICES environment variable.

Returns:

A ClusterSpec containing host information retrieved from Slurm's environment variables.

get_task_info

get_task_info()

Returns job name and task_index for the process which calls this.

This returns the job name and task index for the process which calls this function according to its rank and cluster specification. The job name and task index are set after a cluster is constructed by cluster_spec otherwise defaults to None.

Returns:

A string specifying job name the process belongs to and an integner specifying the task index the process belongs to in that job.

master

master(
    task_type=None,
    task_index=None,
    rpc_layer=None
)

Returns the master string for connecting to a TensorFlow master.

Args:

  • task_type: (Optional) Overrides the default auto-selected task type.
  • task_index: (Optional) Overrides the default auto-slected task index.
  • rpc_layer: (Optional) Overrides the default RPC protocol TensorFlow uses to communicate across nodes.

Returns:

A connection string for connecting to a TensorFlow master.

num_accelerators

num_accelerators(
    task_type=None,
    task_index=None,
    accelerator_type='GPU',
    config_proto=None
)

Returns the number of accelerator cores per worker.

This returns the number of accelerator cores (such as GPUs and TPUs) available per worker. If workers only has CPU cores available, then this should return 0. This method will query the master for this information if it is not otherwise known.

Optionally, we allow callers to specify the task_type, task_index, and rpc_layer, if they want to target a specific TensorFlow process to query the number of accelerators. This is to support heterogenous environments, where the number of accelerators cores per host is different.

Args:

  • task_type: (Optional) The type of the TensorFlow task of the machine we want to query.
  • task_index: (Optional) The index of the TensorFlow task of the machine we want to query.
  • accelerator_type: (Optional) The type of accelerator we are trying to query (defaults to 'GPU').
  • config_proto: (Optional) Configuration for starting a new session to query how many accelerator cores it has.