BatchStartTask Class

Batch will retry Tasks when a recovery operation is triggered on a Node. Examples of recovery operations include (but are not limited to) when an unhealthy Node is rebooted or a Compute Node disappeared due to host failure. Retries due to recovery operations are independent of and are not counted against the maxTaskRetryCount. Even if the maxTaskRetryCount is 0, an internal retry due to a recovery operation may occur. Because of this, all Tasks should be idempotent. This means Tasks need to tolerate being interrupted and restarted without causing any corruption or duplicate data. The best practice for long running Tasks is to use some form of checkpointing. In some cases the StartTask may be re-run even though the Compute Node was not rebooted. Special care should be taken to avoid StartTasks which create breakaway process or install/launch services from the StartTask working directory, as this will block Batch from being able to re-run the StartTask.

Constructor

BatchStartTask(*args: Any, **kwargs: Any)

Variables

Name	Description
command_line	str The command line of the StartTask. The command line does not run under a shell, and therefore cannot take advantage of shell features such as environment variable expansion. If you want to take advantage of such features, you should invoke the shell in the command line, for example using "cmd /c MyCommand" in Windows or "/bin/sh -c MyCommand" in Linux. If the command line refers to file paths, it should use a relative path (relative to the Task working directory), or use the Batch provided environment variable (https://learn.microsoft.com/azure/batch/batch-compute-node-environment-variables). Required.
container_settings	BatchTaskContainerSettings The settings for the container under which the StartTask runs. When this is specified, all directories recursively below the AZ_BATCH_NODE_ROOT_DIR (the root of Azure Batch directories on the node) are mapped into the container, all Task environment variables are mapped into the container, and the Task command line is executed in the container. Files produced in the container outside of AZ_BATCH_NODE_ROOT_DIR might not be reflected to the host disk, meaning that Batch file APIs will not be able to access those files.
resource_files	list[ResourceFile] A list of files that the Batch service will download to the Compute Node before running the command line. There is a maximum size for the list of resource files. When the max size is exceeded, the request will fail and the response error code will be RequestEntityTooLarge. If this occurs, the collection of ResourceFiles must be reduced in size. This can be achieved using .zip files, Application Packages, or Docker Containers. Files listed under this element are located in the Task's working directory.
environment_settings	list[EnvironmentSetting] A list of environment variable settings for the StartTask.
user_identity	UserIdentity The user identity under which the StartTask runs. If omitted, the Task runs as a non-administrative user unique to the Task.
max_task_retry_count	int The maximum number of times the Task may be retried. The Batch service retries a Task if its exit code is nonzero. Note that this value specifically controls the number of retries. The Batch service will try the Task once, and may then retry up to this limit. For example, if the maximum retry count is 3, Batch tries the Task up to 4 times (one initial try and 3 retries). If the maximum retry count is 0, the Batch service does not retry the Task. If the maximum retry count is -1, the Batch service retries the Task without limit, however this is not recommended for a start task or any task. The default value is 0 (no retries).
wait_for_success	bool Whether the Batch service should wait for the StartTask to complete successfully (that is, to exit with exit code 0) before scheduling any Tasks on the Compute Node. If true and the StartTask fails on a Node, the Batch service retries the StartTask up to its maximum retry count (maxTaskRetryCount). If the Task has still not completed successfully after all retries, then the Batch service marks the Node unusable, and will not schedule Tasks to it. This condition can be detected via the Compute Node state and failure info details. If false, the Batch service will not wait for the StartTask to complete. In this case, other Tasks can start executing on the Compute Node while the StartTask is still running; and even if the StartTask fails, new Tasks will continue to be scheduled on the Compute Node. The default is true.

Methods

as_dict	Return a dict that can be turned into json using json.dump.
clear	Remove all items from D.
copy
get	Get the value for key if key is in the dictionary, else default. :param str key: The key to look up. :param any default: The value to return if key is not in the dictionary. Defaults to None :returns: D[k] if k in D, else d. :rtype: any
items
keys
pop	Removes specified key and return the corresponding value. :param str key: The key to pop. :param any default: The value to return if key is not in the dictionary :returns: The value corresponding to the key. :rtype: any :raises KeyError: If key is not found and default is not given.
popitem	Removes and returns some (key, value) pair :returns: The (key, value) pair. :rtype: tuple :raises KeyError: if D is empty.
setdefault	Same as calling D.get(k, d), and setting D[k]=d if k not found :param str key: The key to look up. :param any default: The value to set if key is not in the dictionary :returns: D[k] if k in D, else d. :rtype: any
update	Updates D from mapping/iterable E and F. :param any args: Either a mapping object or an iterable of key-value pairs.
values

as_dict

Return a dict that can be turned into json using json.dump.

as_dict(*, exclude_readonly: bool = False) -> dict[str, Any]

Keyword-Only Parameters

Name	Description
exclude_readonly	bool Whether to remove the readonly properties. Default value: False

Returns

Type	Description
dict	A dict JSON compatible object

clear

Remove all items from D.

clear() -> None

copy

copy() -> Model

get

Get the value for key if key is in the dictionary, else default. :param str key: The key to look up. :param any default: The value to return if key is not in the dictionary. Defaults to None :returns: D[k] if k in D, else d. :rtype: any

get(key: str, default: Any = None) -> Any

Parameters

Name	Description
key Required
default	Default value: None

items

items() -> ItemsView[str, Any]

Returns

Type	Description
ItemsView	set-like object providing a view on D's items

keys

keys() -> KeysView[str]

Returns

Type	Description
KeysView	a set-like object providing a view on D's keys

pop

Removes specified key and return the corresponding value. :param str key: The key to pop. :param any default: The value to return if key is not in the dictionary :returns: The value corresponding to the key. :rtype: any :raises KeyError: If key is not found and default is not given.

pop(key: str, default: ~typing.Any = <object object>) -> Any

Parameters

Name	Description
key Required
default

popitem

Removes and returns some (key, value) pair :returns: The (key, value) pair. :rtype: tuple :raises KeyError: if D is empty.

popitem() -> tuple[str, Any]

setdefault

Same as calling D.get(k, d), and setting D[k]=d if k not found :param str key: The key to look up. :param any default: The value to set if key is not in the dictionary :returns: D[k] if k in D, else d. :rtype: any

setdefault(key: str, default: ~typing.Any = <object object>) -> Any

Parameters

Name	Description
key Required
default

update

Updates D from mapping/iterable E and F. :param any args: Either a mapping object or an iterable of key-value pairs.

update(*args: Any, **kwargs: Any) -> None

values

values() -> ValuesView[Any]

Returns

Type	Description
ValuesView	an object providing a view on D's values

Attributes

command_line

The command line of the StartTask. The command line does not run under a shell, and therefore cannot take advantage of shell features such as environment variable expansion. If you want to take advantage of such features, you should invoke the shell in the command line, for example using "cmd /c MyCommand" in Windows or "/bin/sh -c MyCommand" in Linux. If the command line refers to file paths, it should use a relative path (relative to the Task working directory), or use the Batch provided environment variable (https://learn.microsoft.com/azure/batch/batch-compute-node-environment-variables). Required.

command_line: str

container_settings

The settings for the container under which the StartTask runs. When this is specified, all directories recursively below the AZ_BATCH_NODE_ROOT_DIR (the root of Azure Batch directories on the node) are mapped into the container, all Task environment variables are mapped into the container, and the Task command line is executed in the container. Files produced in the container outside of AZ_BATCH_NODE_ROOT_DIR might not be reflected to the host disk, meaning that Batch file APIs will not be able to access those files.

container_settings: _models.BatchTaskContainerSettings | None

environment_settings

A list of environment variable settings for the StartTask.

environment_settings: list['_models.EnvironmentSetting'] | None

max_task_retry_count

The maximum number of times the Task may be retried. The Batch service retries a Task if its exit code is nonzero. Note that this value specifically controls the number of retries. The Batch service will try the Task once, and may then retry up to this limit. For example, if the maximum retry count is 3, Batch tries the Task up to 4 times (one initial try and 3 retries). If the maximum retry count is 0, the Batch service does not retry the Task. If the maximum retry count is -1, the Batch service retries the Task without limit, however this is not recommended for a start task or any task. The default value is 0 (no retries).

max_task_retry_count: int | None

resource_files

A list of files that the Batch service will download to the Compute Node before running the command line. There is a maximum size for the list of resource files. When the max size is exceeded, the request will fail and the response error code will be RequestEntityTooLarge. If this occurs, the collection of ResourceFiles must be reduced in size. This can be achieved using .zip files, Application Packages, or Docker Containers. Files listed under this element are located in the Task's working directory.

resource_files: list['_models.ResourceFile'] | None

user_identity

The user identity under which the StartTask runs. If omitted, the Task runs as a non-administrative user unique to the Task.

user_identity: _models.UserIdentity | None

wait_for_success

Whether the Batch service should wait for the StartTask to complete successfully (that is, to exit with exit code 0) before scheduling any Tasks on the Compute Node. If true and the StartTask fails on a Node, the Batch service retries the StartTask up to its maximum retry count (maxTaskRetryCount). If the Task has still not completed successfully after all retries, then the Batch service marks the Node unusable, and will not schedule Tasks to it. This condition can be detected via the Compute Node state and failure info details. If false, the Batch service will not wait for the StartTask to complete. In this case, other Tasks can start executing on the Compute Node while the StartTask is still running; and even if the StartTask fails, new Tasks will continue to be scheduled on the Compute Node. The default is true.

wait_for_success: bool | None