CLI (v2) sweep job YAML schema

APPLIES TO: Azure CLI ml extension v2 (current)

The source JSON schema can be found at https://azuremlschemas.azureedge.net/latest/sweepJob.schema.json.

Note

The YAML syntax detailed in this document is based on the JSON schema for the latest version of the ML CLI v2 extension. This syntax is guaranteed only to work with the latest version of the ML CLI v2 extension. You can find the schemas for older extension versions at https://azuremlschemasprod.azureedge.net/.

YAML syntax

Key Type Description Allowed values Default value
$schema string The YAML schema. If you use the Azure Machine Learning VS Code extension to author the YAML file, including $schema at the top of your file enables you to invoke schema and resource completions.
type const Required. The type of job. sweep sweep
name string Name of the job. Must be unique across all jobs in the workspace. If omitted, Azure ML will autogenerate a GUID for the name.
display_name string Display name of the job in the studio UI. Can be non-unique within the workspace. If omitted, Azure ML will autogenerate a human-readable adjective-noun identifier for the display name.
experiment_name string Experiment name to organize the job under. Each job's run record will be organized under the corresponding experiment in the studio's "Experiments" tab. If omitted, Azure ML will default it to the name of the working directory where the job was created.
description string Description of the job.
tags object Dictionary of tags for the job.
sampling_algorithm object Required. The hyperparameter sampling algorithm to use over the search_space. One of RandomSamplingAlgorithm, GridSamplingAlgorithm,or BayesianSamplingAlgorithm.
search_space object Required. Dictionary of the hyperparameter search space. The key is the name of the hyperparameter and the value is the parameter expression.

Hyperparameters can be referenced in the trial.command using the ${{ search_space.<hyperparameter> }} expression.
search_space.<hyperparameter> object See Parameter expressions for the set of possible expressions to use.
objective.primary_metric string Required. The name of the primary metric reported by each trial job. The metric must be logged in the user's training script using mlflow.log_metric() with the same corresponding metric name.
objective.goal string Required. The optimization goal of the objective.primary_metric. maximize, minimize
early_termination object The early termination policy to use. A trial job is canceled when the criteria of the specified policy are met. If omitted, no early termination policy will be applied. One of BanditPolicy, MedianStoppingPolicy,or TruncationSelectionPolicy.
limits object Limits for the sweep job. See Attributes of the limits key.
compute string Required. Name of the compute target to execute the job on, using the azureml:<compute_name> syntax.
trial object Required. The job template for each trial. Each trial job will be provided with a different combination of hyperparameter values that the system samples from the search_space. See Attributes of the trial key.
inputs object Dictionary of inputs to the job. The key is a name for the input within the context of the job and the value is the input value.

Inputs can be referenced in the command using the ${{ inputs.<input_name> }} expression.
inputs.<input_name> number, integer, boolean, string or object One of a literal value (of type number, integer, boolean, or string) or an object containing a job input data specification.
outputs object Dictionary of output configurations of the job. The key is a name for the output within the context of the job and the value is the output configuration.

Outputs can be referenced in the command using the ${{ outputs.<output_name> }} expression.
outputs.<output_name> object You can leave the object empty, in which case by default the output will be of type uri_folder and Azure ML will system-generate an output location for the output. File(s) to the output directory will be written via read-write mount. If you want to specify a different mode for the output, provide an object containing the job output specification.
identity object The identity is used for data accessing. It can be UserIdentityConfiguration, ManagedIdentityConfiguration or None. If UserIdentityConfiguration, the identity of job submitter will be used to access input data and write result to output folder, otherwise, the managed identity of the compute target will be used.

Sampling algorithms

RandomSamplingAlgorithm

Key Type Description Allowed values Default value
type const Required. The type of sampling algorithm. random
seed integer A random seed to use for initializing the random number generation. If omitted, the default seed value will be null.
rule string The type of random sampling to use. The default, random, will use simple uniform random sampling, while sobol will use the Sobol quasirandom sequence. random, sobol random

GridSamplingAlgorithm

Key Type Description Allowed values
type const Required. The type of sampling algorithm. grid

BayesianSamplingAlgorithm

Key Type Description Allowed values
type const Required. The type of sampling algorithm. bayesian

Early termination policies

BanditPolicy

Key Type Description Allowed values Default value
type const Required. The type of policy. bandit
slack_factor number The ratio used to calculate the allowed distance from the best performing trial. One of slack_factor or slack_amount is required.
slack_amount number The absolute distance allowed from the best performing trial. One of slack_factor or slack_amount is required.
evaluation_interval integer The frequency for applying the policy. 1
delay_evaluation integer The number of intervals for which to delay the first policy evaluation. If specified, the policy applies on every multiple of evaluation_interval that is greater than or equal to delay_evaluation. 0

MedianStoppingPolicy

Key Type Description Allowed values Default value
type const Required. The type of policy. median_stopping
evaluation_interval integer The frequency for applying the policy. 1
delay_evaluation integer The number of intervals for which to delay the first policy evaluation. If specified, the policy applies on every multiple of evaluation_interval that is greater than or equal to delay_evaluation. 0

TruncationSelectionPolicy

Key Type Description Allowed values Default value
type const Required. The type of policy. truncation_selection
truncation_percentage integer Required. The percentage of trial jobs to cancel at each evaluation interval.
evaluation_interval integer The frequency for applying the policy. 1
delay_evaluation integer The number of intervals for which to delay the first policy evaluation. If specified, the policy applies on every multiple of evaluation_interval that is greater than or equal to delay_evaluation. 0

Parameter expressions

choice

Key Type Description Allowed values
type const Required. The type of expression. choice
values array Required. The list of discrete values to choose from.

randint

Key Type Description Allowed values
type const Required. The type of expression. randint
upper integer Required. The exclusive upper bound for the range of integers.

qlognormal, qnormal

Key Type Description Allowed values
type const Required. The type of expression. qlognormal, qnormal
mu number Required. The mean of the normal distribution.
sigma number Required. The standard deviation of the normal distribution.
q integer Required. The smoothing factor.

qloguniform, quniform

Key Type Description Allowed values
type const Required. The type of expression. qloguniform, quniform
min_value number Required. The minimum value in the range (inclusive).
max_value number Required. The maximum value in the range (inclusive).
q integer Required. The smoothing factor.

lognormal, normal

Key Type Description Allowed values
type const Required. The type of expression. lognormal, normal
mu number Required. The mean of the normal distribution.
sigma number Required. The standard deviation of the normal distribution.

loguniform

Key Type Description Allowed values
type const Required. The type of expression. loguniform
min_value number Required. The minimum value in the range will be exp(min_value) (inclusive).
max_value number Required. The maximum value in the range will be exp(max_value) (inclusive).

uniform

Key Type Description Allowed values
type const Required. The type of expression. uniform
min_value number Required. The minimum value in the range (inclusive).
max_value number Required. The maximum value in the range (inclusive).

Attributes of the limits key

Key Type Description Default value
max_total_trials integer The maximum time in seconds the job is allowed to run. Once this limit is reached, the system will cancel the job. 1000
max_concurrent_trials integer Defaults to max_total_trials.
timeout integer The maximum time in seconds the entire sweep job is allowed to run. Once this limit is reached, the system will cancel the sweep job, including all its trials. 604800
trial_timeout integer The maximum time in seconds each trial job is allowed to run. Once this limit is reached, the system will cancel the trial.

Attributes of the trial key

Key Type Description Default value
command string Required. The command to execute.
code string Local path to the source code directory to be uploaded and used for the job.
environment string or object Required. The environment to use for the job. This can be either a reference to an existing versioned environment in the workspace or an inline environment specification.

To reference an existing environment, use the azureml:<environment-name>:<environment-version> syntax.

To define an environment inline, follow the Environment schema. Exclude the name and version properties as they aren't supported for inline environments.
environment_variables object Dictionary of environment variable name-value pairs to set on the process where the command is executed.
distribution object The distribution configuration for distributed training scenarios. One of MpiConfiguration, PyTorchConfiguration, or TensorFlowConfiguration.
resources.instance_count integer The number of nodes to use for the job. 1

Distribution configurations

MpiConfiguration
Key Type Description Allowed values
type const Required. Distribution type. mpi
process_count_per_instance integer Required. The number of processes per node to launch for the job.
PyTorchConfiguration
Key Type Description Allowed values Default value
type const Required. Distribution type. pytorch
process_count_per_instance integer The number of processes per node to launch for the job. 1
TensorFlowConfiguration
Key Type Description Allowed values Default value
type const Required. Distribution type. tensorflow
worker_count integer The number of workers to launch for the job. Defaults to resources.instance_count.
parameter_server_count integer The number of parameter servers to launch for the job. 0

Job inputs

Key Type Description Allowed values Default value
type string The type of job input. Specify uri_file for input data that points to a single file source, or uri_folder for input data that points to a folder source. Learn more about data access. uri_file, uri_folder, mltable, mlflow_model uri_folder
path string The path to the data to use as input. This can be specified in a few ways:

- A local path to the data source file or folder, for example, path: ./iris.csv. The data will get uploaded during job submission.

- A URI of a cloud path to the file or folder to use as the input. Supported URI types are azureml, https, wasbs, abfss, adl. For more information on using the azureml:// URI format, see Core yaml syntax.

- An existing registered Azure ML data asset to use as the input. To reference a registered data asset, use the azureml:<data_name>:<data_version> syntax or azureml:<data_name>@latest (to reference the latest version of that data asset), for example, path: azureml:cifar10-data:1 or path: azureml:cifar10-data@latest.
mode string Mode of how the data should be delivered to the compute target.

For read-only mount (ro_mount), the data will be consumed as a mount path. A folder will be mounted as a folder and a file will be mounted as a file. Azure ML will resolve the input to the mount path.

For download mode the data will be downloaded to the compute target. Azure ML will resolve the input to the downloaded path.

If you only want the URL of the storage location of the data artifact(s) rather than mounting or downloading the data itself, you can use the direct mode. This will pass in the URL of the storage location as the job input. In this case you're fully responsible for handling credentials to access the storage.
ro_mount, download, direct ro_mount

Job outputs

Key Type Description Allowed values Default value
type string The type of job output. For the default uri_folder type, the output will correspond to a folder. uri_file, uri_folder, mltable, mlflow_model uri_folder
mode string Mode of how output file(s) will get delivered to the destination storage. For read-write mount mode (rw_mount) the output directory will be a mounted directory. For upload mode the file(s) written will get uploaded at the end of the job. rw_mount, upload rw_mount

Identity configurations

UserIdentityConfiguration

Key Type Description Allowed values
type const Required. Identity type. user_identity

ManagedIdentityConfiguration

Key Type Description Allowed values
type const Required. Identity type. managed or managed_identity

Remarks

The az ml job command can be used for managing Azure Machine Learning jobs.

Examples

Examples are available in the examples GitHub repository. Several are shown below.

YAML: hello sweep

$schema: https://azuremlschemas.azureedge.net/latest/sweepJob.schema.json
type: sweep
trial:
  command: >-
    python hello-sweep.py
    --A ${{inputs.A}}
    --B ${{search_space.B}}
    --C ${{search_space.C}}
  code: src
  environment: azureml:AzureML-sklearn-1.0-ubuntu20.04-py38-cpu@latest
inputs:
  A: 0.5
compute: azureml:cpu-cluster
sampling_algorithm: random
search_space:
  B:
    type: choice
    values: ["hello", "world", "hello_world"]
  C:
    type: uniform
    min_value: 0.1
    max_value: 1.0
objective:
  goal: minimize
  primary_metric: random_metric
limits:
  max_total_trials: 4
  max_concurrent_trials: 2
  timeout: 3600
display_name: hello-sweep-example
experiment_name: hello-sweep-example
description: Hello sweep job example.

YAML: basic Python model hyperparameter tuning

$schema: https://azuremlschemas.azureedge.net/latest/sweepJob.schema.json
type: sweep
trial:
  code: src
  command: >-
    python main.py 
    --iris-csv ${{inputs.iris_csv}}
    --C ${{search_space.C}}
    --kernel ${{search_space.kernel}}
    --coef0 ${{search_space.coef0}}
  environment: azureml:AzureML-sklearn-0.24-ubuntu18.04-py37-cpu@latest
inputs:
  iris_csv: 
    type: uri_file
    path: wasbs://datasets@azuremlexamples.blob.core.windows.net/iris.csv
compute: azureml:cpu-cluster
sampling_algorithm: random
search_space:
  C:
    type: uniform
    min_value: 0.5
    max_value: 0.9
  kernel:
    type: choice
    values: ["rbf", "linear", "poly"]
  coef0:
    type: uniform
    min_value: 0.1
    max_value: 1
objective:
  goal: minimize
  primary_metric: training_f1_score
limits:
  max_total_trials: 20
  max_concurrent_trials: 10
  timeout: 7200
display_name: sklearn-iris-sweep-example
experiment_name: sklearn-iris-sweep-example
description: Sweep hyperparemeters for training a scikit-learn SVM on the Iris dataset.

Next steps