Experiment Config Reference

A config file is needed when creating an experiment. This document describes the rules to write a config file and provides some examples.

Note

  1. This document lists field names with camelCase. If users use these fields in the pythonic way with NNI Python APIs (e.g., nni.experiment), the field names should be converted to snake_case.

  2. In this document, the type of fields are formatted as Python type hint. Therefore JSON objects are called dict and arrays are called list.

  1. Some fields take a path to a file or directory. Unless otherwise noted, both absolute path and relative path are supported, and ~ will be expanded to the home directory.

    • When written in the YAML file, relative paths are relative to the directory containing that file.

    • When assigned in Python code, relative paths are relative to the current working directory.

    • All relative paths are converted to absolute when loading YAML file into Python class, and when saving Python class to YAML file.

  2. Setting a field to None or null is equivalent to not setting the field.

Examples

Local Mode

experimentName: MNIST
searchSpaceFile: search_space.json
trialCommand: python mnist.py
trialCodeDirectory: .
trialGpuNumber: 1
trialConcurrency: 2
maxExperimentDuration: 24h
maxTrialNumber: 100
tuner:
  name: TPE
  classArgs:
    optimize_mode: maximize
trainingService:
  platform: local
  useActiveGpu: True

Local Mode (Inline Search Space)

searchSpace:
  batch_size:
    _type: choice
    _value: [16, 32, 64]
  learning_rate:
    _type: loguniform
    _value: [0.0001, 0.1]
trialCommand: python mnist.py
trialGpuNumber: 1
trialConcurrency: 2
tuner:
  name: TPE
  classArgs:
    optimize_mode: maximize
trainingService:
  platform: local
  useActiveGpu: True

Remote Mode

experimentName: MNIST
searchSpaceFile: search_space.json
trialCommand: python mnist.py
trialCodeDirectory: .
trialGpuNumber: 1
trialConcurrency: 2
maxExperimentDuration: 24h
maxTrialNumber: 100
tuner:
  name: TPE
  classArgs:
    optimize_mode: maximize
trainingService:
  platform: remote
  machineList:
    - host: 11.22.33.44
      user: alice
      password: xxxxx
    - host: my.domain.com
      user: bob
      sshKeyFile: ~/.ssh/id_rsa

Reference

ExperimentConfig

experimentName

Mnemonic name of the experiment, which will be shown in WebUI and nnictl.

type: Optional[str]

searchSpaceFile

Path to the JSON file containing the search space.

type: Optional[str]

Search space format is determined by tuner. The common format for built-in tuners is documented here.

Mutually exclusive to searchSpace.

searchSpace

Search space object.

type: Optional[JSON]

The format is determined by tuner. Common format for built-in tuners is documented here.

Note that None means “no such field” so empty search space should be written as {}.

Mutually exclusive to searchSpaceFile.

trialCommand

Command to launch trial.

type: str

The command will be executed in bash on Linux and macOS, and in PowerShell on Windows.

Note that using python3 on Linux and macOS, and using python on Windows.

trialCodeDirectory

Path to the directory containing trial source files.

type: str

default: "."

All files in this directory will be sent to the training machine, unless in the .nniignore file. (See nniignore for details.)

trialConcurrency

Specify how many trials should be run concurrently.

type: int

The real concurrency also depends on hardware resources and may be less than this value.

trialGpuNumber

Number of GPUs used by each trial.

type: Optional[int]

This field might have slightly different meanings for various training services, especially when set to 0 or None. See training service’s document for details.

In local mode, setting the field to 0 will prevent trials from accessing GPU (by empty CUDA_VISIBLE_DEVICES). And when set to None, trials will be created and scheduled as if they did not use GPU, but they can still use all GPU resources if they want.

maxExperimentDuration

Limit the duration of this experiment if specified.

type: Optional[str]

format: number + s|m|h|d

examples: "10m", "0.5h"

When time runs out, the experiment will stop creating trials but continue to serve WebUI.

maxTrialNumber

Limit the number of trials to create if specified.

type: Optional[int]

When the budget runs out, the experiment will stop creating trials but continue to serve WebUI.

nniManagerIp

IP of the current machine, used by training machines to access NNI manager. Not used in local mode.

type: Optional[str]

If not specified, IPv4 address of eth0 will be used.

Except for the local mode, it is highly recommended to set this field manually.

useAnnotation

Enable annotation.

type: bool

default: False

When using annotation, searchSpace and searchSpaceFile should not be specified manually.

debug

Enable debug mode.

type: bool

default: False

When enabled, logging will be more verbose and some internal validation will be loosened.

logLevel

Set log level of the whole system.

type: Optional[str]

values: "trace", "debug", "info", "warning", "error", "fatal"

Defaults to “info” or “debug”, depending on debug option. When debug mode is enabled, Loglevel is set to “debug”, otherwise, Loglevel is set to “info”.

Most modules of NNI will be affected by this value, including NNI manager, tuner, training service, etc.

The exception is trial, whose logging level is directly managed by trial code.

For Python modules, “trace” acts as logging level 0 and “fatal” acts as logging.CRITICAL.

experimentWorkingDirectory

Specify the directory to place log, checkpoint, metadata, and other run-time stuff.

type: Optional[str]

By default uses ~/nni-experiments.

NNI will create a subdirectory named by experiment ID, so it is safe to use the same directory for multiple experiments.

tunerGpuIndices

Limit the GPUs visible to tuner, assessor, and advisor.

type: Optional[list[int] | str | int]

This will be the CUDA_VISIBLE_DEVICES environment variable of tuner process.

Because tuner, assessor, and advisor run in the same process, this option will affect them all.

tuner

Specify the tuner.

type: Optional AlgorithmConfig

The built-in tuners can be found here and you can follow this tutorial to customize a new tuner.

assessor

Specify the assessor.

type: Optional AlgorithmConfig

The built-in assessors can be found here and you can follow this tutorial to customize a new assessor.

advisor

Specify the advisor.

type: Optional AlgorithmConfig

NNI provides two built-in advisors: BOHB and Hyperband, and you can follow this tutorial to customize a new advisor.

trainingService

Specify the training service.

type: TrainingServiceConfig

sharedStorage

Configure the shared storage, detailed usage can be found here.

type: Optional SharedStorageConfig

AlgorithmConfig

AlgorithmConfig describes a tuner / assessor / advisor algorithm.

For customized algorithms, there are two ways to describe them:

  1. Register the algorithm to use it like built-in. (preferred)

  2. Specify code directory and class name directly.

name

Name of the built-in or registered algorithm.

type: str for the built-in and registered algorithm, None for other customized algorithms.

className

Qualified class name of not registered customized algorithm.

type: None for the built-in and registered algorithm, str for other customized algorithms.

example: "my_tuner.MyTuner"

codeDirectory

Path to the directory containing the customized algorithm class.

type: None for the built-in and registered algorithm, str for other customized algorithms.

classArgs

Keyword arguments passed to algorithm class’ constructor.

type: Optional[dict[str, Any]]

See algorithm’s document for supported value.

TrainingServiceConfig

One of the following:

For Kubeflow, FrameworkController, and AdaptDL training platforms, it is suggested to use v1 config schema for now.

LocalConfig

Detailed usage can be found here.

platform

Constant string "local".

useActiveGpu

Specify whether NNI should submit trials to GPUs occupied by other tasks.

type: Optional[bool]

Must be set when trialGpuNumber greater than zero.

Following processes can make GPU “active”:

  • non-NNI CUDA programs

  • graphical desktop

  • trials submitted by other NNI instances, if you have more than one NNI experiments running at same time

  • other users’ CUDA programs, if you are using a shared server

If you are using a graphical OS like Windows 10 or Ubuntu desktop, set this field to True, otherwise, the GUI will prevent NNI from launching any trial.

When you create multiple NNI experiments and useActiveGpu is set to True, they will submit multiple trials to the same GPU(s) simultaneously.

maxTrialNumberPerGpu

Specify how many trials can share one GPU.

type: int

default: 1

gpuIndices

Limit the GPUs visible to trial processes.

type: Optional[list[int] | str | int]

If trialGpuNumber is less than the length of this value, only a subset will be visible to each trial.

This will be used as CUDA_VISIBLE_DEVICES environment variable.

RemoteConfig

Detailed usage can be found here.

platform

Constant string "remote".

machineList

List of training machines.

type: list of RemoteMachineConfig

reuseMode

Enable reuse mode.

type: bool

RemoteMachineConfig
host

IP or hostname (domain name) of the machine.

type: str

port

SSH service port.

type: int

default: 22

user

Login user name.

type: str

password

Login password.

type: Optional[str]

If not specified, sshKeyFile will be used instead.

sshKeyFile

Path to sshKeyFile (identity file).

type: Optional[str]

Only used when password is not specified.

sshPassphrase

Passphrase of SSH identity file.

type: Optional[str]

useActiveGpu

Specify whether NNI should submit trials to GPUs occupied by other tasks.

type: bool

default: False

Must be set when trialGpuNumber greater than zero.

Following processes can make GPU “active”:

  • non-NNI CUDA programs

  • graphical desktop

  • trials submitted by other NNI instances, if you have more than one NNI experiments running at same time

  • other users’ CUDA programs, if you are using a shared server

If your remote machine is a graphical OS like Ubuntu desktop, set this field to True, otherwise, the GUI will prevent NNI from launching any trial.

When you create multiple NNI experiments and useActiveGpu is set to True, they will submit multiple trials to the same GPU(s) simultaneously.

maxTrialNumberPerGpu

Specify how many trials can share one GPU.

type: int

default: 1

gpuIndices

Limit the GPUs visible to trial processes.

type: Optional[list[int] | str | int]

If trialGpuNumber is less than the length of this value, only a subset will be visible to each trial.

This will be used as CUDA_VISIBLE_DEVICES environment variable.

pythonPath

Specify a Python environment.

type: Optional[str]

This path will be inserted at the front of PATH. Here are some examples:

  • (linux) pythonPath: /opt/python3.7/bin

  • (windows) pythonPath: C:/Python37

If you are working on Anaconda, there is some difference. On Windows, you also have to add ../script and ../Library/bin separated by ;. Examples are as below:

  • (linux anaconda) pythonPath: /home/yourname/anaconda3/envs/myenv/bin/

  • (windows anaconda) pythonPath: C:/Users/yourname/.conda/envs/myenv;C:/Users/yourname/.conda/envs/myenv/Scripts;C:/Users/yourname/.conda/envs/myenv/Library/bin

This is useful if preparing steps vary for different machines.

OpenpaiConfig

Detailed usage can be found here.

platform

Constant string "openpai".

host

Hostname of OpenPAI service.

type: str

This may include https:// or http:// prefix.

HTTPS will be used by default.

username

OpenPAI user name.

type: str

token

OpenPAI user token.

type: str

This can be found in your OpenPAI user settings page.

trialCpuNumber

Specify the CPU number of each trial to be used in OpenPAI container.

type: int

trialMemorySize

Specify the memory size of each trial to be used in OpenPAI container.

type: str

format: number + tb|gb|mb|kb

examples: "8gb", "8192mb"

storageConfigName

Specify the storage name used in OpenPAI.

type: str

dockerImage

Name and tag of docker image to run the trials.

type: str

default: "msranni/nni:latest"

localStorageMountPoint

Mount point of storage service (typically NFS) on the local machine.

type: str

containerStorageMountPoint

Mount point of storage service (typically NFS) in docker container.

type: str

This must be an absolute path.

reuseMode

Enable reuse mode.

type: bool

default: False

openpaiConfig

Embedded OpenPAI config file.

type: Optional[JSON]

openpaiConfigFile

Path to OpenPAI config file.

type: Optional[str]

An example can be found here.

AmlConfig

Detailed usage can be found here.

platform

Constant string "aml".

dockerImage

Name and tag of docker image to run the trials.

type: str

default: "msranni/nni:latest"

subscriptionId

Azure subscription ID.

type: str

resourceGroup

Azure resource group name.

type: str

workspaceName

Azure workspace name.

type: str

computeTarget

AML compute cluster name.

type: str

HybridConfig

Currently only support LocalConfig, RemoteConfig, OpenpaiConfig and AmlConfig . Detailed usage can be found here.

type: list of TrainingServiceConfig

SharedStorageConfig

Detailed usage can be found here.

nfsConfig

storageType

Constant string "NFS".

localMountPoint

The path that the storage has been or will be mounted in the local machine.

type: str

If the path does not exist, it will be created automatically. Recommended to use an absolute path, i.e. /tmp/nni-shared-storage.

remoteMountPoint

The path that the storage will be mounted in the remote achine.

type: str

If the path does not exist, it will be created automatically. Recommended to use a relative path. i.e. ./nni-shared-storage.

localMounted

Specify the object and status to mount the shared storage.

type: str

values: "usermount", "nnimount", "nomount"

usermount means the user has already mounted this storage on localMountPoint. nnimount means NNI will try to mount this storage on localMountPoint. nomount means storage will not mount in the local machine, will support partial storages in the future.

nfsServer

NFS server host.

type: str

exportedDirectory

Exported directory of NFS server, detailed here.

type: str

azureBlobConfig

storageType

Constant string "AzureBlob".

localMountPoint

The path that the storage has been or will be mounted in the local machine.

type: str

If the path does not exist, it will be created automatically. Recommended to use an absolute path, i.e. /tmp/nni-shared-storage.

remoteMountPoint

The path that the storage will be mounted in the remote achine.

type: str

If the path does not exist, it will be created automatically. Recommended to use a relative path. i.e. ./nni-shared-storage.

Note that the directory must be empty when using AzureBlob.

localMounted

Specify the object and status to mount the shared storage.

type: str

values: "usermount", "nnimount", "nomount"

usermount means the user has already mounted this storage on localMountPoint. nnimount means NNI will try to mount this storage on localMountPoint. nomount means storage will not mount in the local machine, will support partial storages in the future.

storageAccountName

Azure storage account name.

type: str

storageAccountKey

Azure storage account key.

type: Optional[str]

When not set storageAccountKey, should use az login with Azure CLI at first and set resourceGroupName.

resourceGroupName

Resource group that AzureBlob container belongs to.

type: Optional[str]

Required if storageAccountKey not set.

containerName

AzureBlob container name.

type: str