Amazon Elastic MapReduce

2015/12/21 - Amazon Elastic MapReduce - 2 updated api methods

DescribeCluster (updated) Link ¶
Changes (response)
{'Cluster': {'Ec2InstanceAttributes': {'ServiceAccessSecurityGroup': 'string'}}}

Provides cluster-level details including status, hardware and software configuration, VPC settings, and so on. For information about the cluster steps, see ListSteps .

Request Syntax

client.describe_cluster(
    ClusterId='string'
)
type ClusterId

string

param ClusterId

[REQUIRED]

The identifier of the cluster to describe.

rtype

dict

returns

Response Syntax

{
    'Cluster': {
        'Id': 'string',
        'Name': 'string',
        'Status': {
            'State': 'STARTING'|'BOOTSTRAPPING'|'RUNNING'|'WAITING'|'TERMINATING'|'TERMINATED'|'TERMINATED_WITH_ERRORS',
            'StateChangeReason': {
                'Code': 'INTERNAL_ERROR'|'VALIDATION_ERROR'|'INSTANCE_FAILURE'|'BOOTSTRAP_FAILURE'|'USER_REQUEST'|'STEP_FAILURE'|'ALL_STEPS_COMPLETED',
                'Message': 'string'
            },
            'Timeline': {
                'CreationDateTime': datetime(2015, 1, 1),
                'ReadyDateTime': datetime(2015, 1, 1),
                'EndDateTime': datetime(2015, 1, 1)
            }
        },
        'Ec2InstanceAttributes': {
            'Ec2KeyName': 'string',
            'Ec2SubnetId': 'string',
            'Ec2AvailabilityZone': 'string',
            'IamInstanceProfile': 'string',
            'EmrManagedMasterSecurityGroup': 'string',
            'EmrManagedSlaveSecurityGroup': 'string',
            'ServiceAccessSecurityGroup': 'string',
            'AdditionalMasterSecurityGroups': [
                'string',
            ],
            'AdditionalSlaveSecurityGroups': [
                'string',
            ]
        },
        'LogUri': 'string',
        'RequestedAmiVersion': 'string',
        'RunningAmiVersion': 'string',
        'ReleaseLabel': 'string',
        'AutoTerminate': True|False,
        'TerminationProtected': True|False,
        'VisibleToAllUsers': True|False,
        'Applications': [
            {
                'Name': 'string',
                'Version': 'string',
                'Args': [
                    'string',
                ],
                'AdditionalInfo': {
                    'string': 'string'
                }
            },
        ],
        'Tags': [
            {
                'Key': 'string',
                'Value': 'string'
            },
        ],
        'ServiceRole': 'string',
        'NormalizedInstanceHours': 123,
        'MasterPublicDnsName': 'string',
        'Configurations': [
            {
                'Classification': 'string',
                'Configurations': {'... recursive ...'},
                'Properties': {
                    'string': 'string'
                }
            },
        ]
    }
}

Response Structure

  • (dict) --

    This output contains the description of the cluster.

    • Cluster (dict) --

      This output contains the details for the requested cluster.

      • Id (string) --

        The unique identifier for the cluster.

      • Name (string) --

        The name of the cluster.

      • Status (dict) --

        The current status details about the cluster.

        • State (string) --

          The current state of the cluster.

        • StateChangeReason (dict) --

          The reason for the cluster status change.

          • Code (string) --

            The programmatic code for the state change reason.

          • Message (string) --

            The descriptive message for the state change reason.

        • Timeline (dict) --

          A timeline that represents the status of a cluster over the lifetime of the cluster.

          • CreationDateTime (datetime) --

            The creation date and time of the cluster.

          • ReadyDateTime (datetime) --

            The date and time when the cluster was ready to execute steps.

          • EndDateTime (datetime) --

            The date and time when the cluster was terminated.

      • Ec2InstanceAttributes (dict) --

        Provides information about the EC2 instances in a cluster grouped by category. For example, key name, subnet ID, IAM instance profile, and so on.

        • Ec2KeyName (string) --

          The name of the Amazon EC2 key pair to use when connecting with SSH into the master node as a user named "hadoop".

        • Ec2SubnetId (string) --

          To launch the job flow in Amazon VPC, set this parameter to the identifier of the Amazon VPC subnet where you want the job flow to launch. If you do not specify this value, the job flow is launched in the normal AWS cloud, outside of a VPC.

          Amazon VPC currently does not support cluster compute quadruple extra large (cc1.4xlarge) instances. Thus, you cannot specify the cc1.4xlarge instance type for nodes of a job flow launched in a VPC.

        • Ec2AvailabilityZone (string) --

          The Availability Zone in which the cluster will run.

        • IamInstanceProfile (string) --

          The IAM role that was specified when the job flow was launched. The EC2 instances of the job flow assume this role.

        • EmrManagedMasterSecurityGroup (string) --

          The identifier of the Amazon EC2 security group for the master node.

        • EmrManagedSlaveSecurityGroup (string) --

          The identifier of the Amazon EC2 security group for the slave nodes.

        • ServiceAccessSecurityGroup (string) --

          The identifier of the Amazon EC2 security group for the Amazon EMR service to access clusters in VPC private subnets.

        • AdditionalMasterSecurityGroups (list) --

          A list of additional Amazon EC2 security group IDs for the master node.

          • (string) --

        • AdditionalSlaveSecurityGroups (list) --

          A list of additional Amazon EC2 security group IDs for the slave nodes.

          • (string) --

      • LogUri (string) --

        The path to the Amazon S3 location where logs for this cluster are stored.

      • RequestedAmiVersion (string) --

        The AMI version requested for this cluster.

      • RunningAmiVersion (string) --

        The AMI version running on this cluster.

      • ReleaseLabel (string) --

        The release label for the Amazon EMR release. For Amazon EMR 3.x and 2.x AMIs, use amiVersion instead instead of ReleaseLabel.

      • AutoTerminate (boolean) --

        Specifies whether the cluster should terminate after completing all steps.

      • TerminationProtected (boolean) --

        Indicates whether Amazon EMR will lock the cluster to prevent the EC2 instances from being terminated by an API call or user intervention, or in the event of a cluster error.

      • VisibleToAllUsers (boolean) --

        Indicates whether the job flow is visible to all IAM users of the AWS account associated with the job flow. If this value is set to true , all IAM users of that AWS account can view and manage the job flow if they have the proper policy permissions set. If this value is false , only the IAM user that created the cluster can view and manage it. This value can be changed using the SetVisibleToAllUsers action.

      • Applications (list) --

        The applications installed on this cluster.

        • (dict) --

          An application is any Amazon or third-party software that you can add to the cluster. This structure contains a list of strings that indicates the software to use with the cluster and accepts a user argument list. Amazon EMR accepts and forwards the argument list to the corresponding installation script as bootstrap action argument. For more information, see Launch a Job Flow on the MapR Distribution for Hadoop . Currently supported values are:

          • "mapr-m3" - launch the job flow using MapR M3 Edition.

          • "mapr-m5" - launch the job flow using MapR M5 Edition.

          • "mapr" with the user arguments specifying "--edition,m3" or "--edition,m5" - launch the job flow using MapR M3 or M5 Edition, respectively.

          Note

          In Amazon EMR releases 4.0 and greater, the only accepted parameter is the application name. To pass arguments to applications, you supply a configuration for each application.

          • Name (string) --

            The name of the application.

          • Version (string) --

            The version of the application.

          • Args (list) --

            Arguments for Amazon EMR to pass to the application.

            • (string) --

          • AdditionalInfo (dict) --

            This option is for advanced users only. This is meta information about third-party applications that third-party vendors use for testing purposes.

            • (string) --

              • (string) --

      • Tags (list) --

        A list of tags associated with a cluster.

        • (dict) --

          A key/value pair containing user-defined metadata that you can associate with an Amazon EMR resource. Tags make it easier to associate clusters in various ways, such as grouping clusters to track your Amazon EMR resource allocation costs. For more information, see Tagging Amazon EMR Resources .

      • ServiceRole (string) --

        The IAM role that will be assumed by the Amazon EMR service to access AWS resources on your behalf.

      • NormalizedInstanceHours (integer) --

        An approximation of the cost of the job flow, represented in m1.small/hours. This value is incremented one time for every hour an m1.small instance runs. Larger instances are weighted more, so an EC2 instance that is roughly four times more expensive would result in the normalized instance hours being incremented by four. This result is only an approximation and does not reflect the actual billing rate.

      • MasterPublicDnsName (string) --

        The public DNS name of the master EC2 instance.

      • Configurations (list) --

        Note

        Amazon EMR releases 4.x or later.

        The list of Configurations supplied to the EMR cluster.

        • (dict) --

          Note

          Amazon EMR releases 4.x or later.

          Specifies a hardware and software configuration of the EMR cluster. This includes configurations for applications and software bundled with Amazon EMR. The Configuration object is a JSON object which is defined by a classification and a set of properties. Configurations can be nested, so a configuration may have its own Configuration objects listed.

          • Classification (string) --

            The classification of a configuration. For more information see, Amazon EMR Configurations .

          • Configurations (list) --

            A list of configurations you apply to this configuration object.

          • Properties (dict) --

            A set of properties supplied to the Configuration object.

            • (string) --

              • (string) --

RunJobFlow (updated) Link ¶
Changes (request)
{'Instances': {'ServiceAccessSecurityGroup': 'string'}}

RunJobFlow creates and starts running a new job flow. The job flow will run the steps specified. Once the job flow completes, the cluster is stopped and the HDFS partition is lost. To prevent loss of data, configure the last step of the job flow to store results in Amazon S3. If the JobFlowInstancesConfig KeepJobFlowAliveWhenNoSteps parameter is set to TRUE , the job flow will transition to the WAITING state rather than shutting down once the steps have completed.

For additional protection, you can set the JobFlowInstancesConfig TerminationProtected parameter to TRUE to lock the job flow and prevent it from being terminated by API call, user intervention, or in the event of a job flow error.

A maximum of 256 steps are allowed in each job flow.

If your job flow is long-running (such as a Hive data warehouse) or complex, you may require more than 256 steps to process your data. You can bypass the 256-step limitation in various ways, including using the SSH shell to connect to the master node and submitting queries directly to the software running on the master node, such as Hive and Hadoop. For more information on how to do this, go to Add More than 256 Steps to a Job Flow in the Amazon Elastic MapReduce Developer's Guide .

For long running job flows, we recommend that you periodically store your results.

Request Syntax

client.run_job_flow(
    Name='string',
    LogUri='string',
    AdditionalInfo='string',
    AmiVersion='string',
    ReleaseLabel='string',
    Instances={
        'MasterInstanceType': 'string',
        'SlaveInstanceType': 'string',
        'InstanceCount': 123,
        'InstanceGroups': [
            {
                'Name': 'string',
                'Market': 'ON_DEMAND'|'SPOT',
                'InstanceRole': 'MASTER'|'CORE'|'TASK',
                'BidPrice': 'string',
                'InstanceType': 'string',
                'InstanceCount': 123,
                'Configurations': [
                    {
                        'Classification': 'string',
                        'Configurations': {'... recursive ...'},
                        'Properties': {
                            'string': 'string'
                        }
                    },
                ]
            },
        ],
        'Ec2KeyName': 'string',
        'Placement': {
            'AvailabilityZone': 'string'
        },
        'KeepJobFlowAliveWhenNoSteps': True|False,
        'TerminationProtected': True|False,
        'HadoopVersion': 'string',
        'Ec2SubnetId': 'string',
        'EmrManagedMasterSecurityGroup': 'string',
        'EmrManagedSlaveSecurityGroup': 'string',
        'ServiceAccessSecurityGroup': 'string',
        'AdditionalMasterSecurityGroups': [
            'string',
        ],
        'AdditionalSlaveSecurityGroups': [
            'string',
        ]
    },
    Steps=[
        {
            'Name': 'string',
            'ActionOnFailure': 'TERMINATE_JOB_FLOW'|'TERMINATE_CLUSTER'|'CANCEL_AND_WAIT'|'CONTINUE',
            'HadoopJarStep': {
                'Properties': [
                    {
                        'Key': 'string',
                        'Value': 'string'
                    },
                ],
                'Jar': 'string',
                'MainClass': 'string',
                'Args': [
                    'string',
                ]
            }
        },
    ],
    BootstrapActions=[
        {
            'Name': 'string',
            'ScriptBootstrapAction': {
                'Path': 'string',
                'Args': [
                    'string',
                ]
            }
        },
    ],
    SupportedProducts=[
        'string',
    ],
    NewSupportedProducts=[
        {
            'Name': 'string',
            'Args': [
                'string',
            ]
        },
    ],
    Applications=[
        {
            'Name': 'string',
            'Version': 'string',
            'Args': [
                'string',
            ],
            'AdditionalInfo': {
                'string': 'string'
            }
        },
    ],
    Configurations=[
        {
            'Classification': 'string',
            'Configurations': {'... recursive ...'},
            'Properties': {
                'string': 'string'
            }
        },
    ],
    VisibleToAllUsers=True|False,
    JobFlowRole='string',
    ServiceRole='string',
    Tags=[
        {
            'Key': 'string',
            'Value': 'string'
        },
    ]
)
type Name

string

param Name

[REQUIRED]

The name of the job flow.

type LogUri

string

param LogUri

The location in Amazon S3 to write the log files of the job flow. If a value is not provided, logs are not created.

type AdditionalInfo

string

param AdditionalInfo

A JSON string for selecting additional features.

type AmiVersion

string

param AmiVersion

Note

For Amazon EMR releases 3.x and 2.x. For Amazon EMR releases 4.x and greater, use ReleaseLabel.

The version of the Amazon Machine Image (AMI) to use when launching Amazon EC2 instances in the job flow. The following values are valid:

  • The version number of the AMI to use, for example, "2.0."

If the AMI supports multiple versions of Hadoop (for example, AMI 1.0 supports both Hadoop 0.18 and 0.20) you can use the JobFlowInstancesConfig HadoopVersion parameter to modify the version of Hadoop from the defaults shown above.

For details about the AMI versions currently supported by Amazon Elastic MapReduce, go to AMI Versions Supported in Elastic MapReduce in the Amazon Elastic MapReduce Developer's Guide.

type ReleaseLabel

string

param ReleaseLabel

Note

Amazon EMR releases 4.x or later.

The release label for the Amazon EMR release. For Amazon EMR 3.x and 2.x AMIs, use amiVersion instead instead of ReleaseLabel.

type Instances

dict

param Instances

[REQUIRED]

A specification of the number and type of Amazon EC2 instances on which to run the job flow.

  • MasterInstanceType (string) --

    The EC2 instance type of the master node.

  • SlaveInstanceType (string) --

    The EC2 instance type of the slave nodes.

  • InstanceCount (integer) --

    The number of Amazon EC2 instances used to execute the job flow.

  • InstanceGroups (list) --

    Configuration for the job flow's instance groups.

    • (dict) --

      Configuration defining a new instance group.

      • Name (string) --

        Friendly name given to the instance group.

      • Market (string) --

        Market type of the Amazon EC2 instances used to create a cluster node.

      • InstanceRole (string) -- [REQUIRED]

        The role of the instance group in the cluster.

      • BidPrice (string) --

        Bid price for each Amazon EC2 instance in the instance group when launching nodes as Spot Instances, expressed in USD.

      • InstanceType (string) -- [REQUIRED]

        The Amazon EC2 instance type for all instances in the instance group.

      • InstanceCount (integer) -- [REQUIRED]

        Target number of instances for the instance group.

      • Configurations (list) --

        Note

        Amazon EMR releases 4.x or later.

        The list of configurations supplied for an EMR cluster instance group. You can specify a separate configuration for each instance group (master, core, and task).

        • (dict) --

          Note

          Amazon EMR releases 4.x or later.

          Specifies a hardware and software configuration of the EMR cluster. This includes configurations for applications and software bundled with Amazon EMR. The Configuration object is a JSON object which is defined by a classification and a set of properties. Configurations can be nested, so a configuration may have its own Configuration objects listed.

          • Classification (string) --

            The classification of a configuration. For more information see, Amazon EMR Configurations .

          • Configurations (list) --

            A list of configurations you apply to this configuration object.

          • Properties (dict) --

            A set of properties supplied to the Configuration object.

            • (string) --

              • (string) --

  • Ec2KeyName (string) --

    The name of the Amazon EC2 key pair that can be used to ssh to the master node as the user called "hadoop."

  • Placement (dict) --

    The Availability Zone the job flow will run in.

    • AvailabilityZone (string) -- [REQUIRED]

      The Amazon EC2 Availability Zone for the job flow.

  • KeepJobFlowAliveWhenNoSteps (boolean) --

    Specifies whether the job flow should be kept alive after completing all steps.

  • TerminationProtected (boolean) --

    Specifies whether to lock the job flow to prevent the Amazon EC2 instances from being terminated by API call, user intervention, or in the event of a job flow error.

  • HadoopVersion (string) --

    The Hadoop version for the job flow. Valid inputs are "0.18" (deprecated), "0.20" (deprecated), "0.20.205" (deprecated), "1.0.3", "2.2.0", or "2.4.0". If you do not set this value, the default of 0.18 is used, unless the AmiVersion parameter is set in the RunJobFlow call, in which case the default version of Hadoop for that AMI version is used.

  • Ec2SubnetId (string) --

    To launch the job flow in Amazon Virtual Private Cloud (Amazon VPC), set this parameter to the identifier of the Amazon VPC subnet where you want the job flow to launch. If you do not specify this value, the job flow is launched in the normal Amazon Web Services cloud, outside of an Amazon VPC.

    Amazon VPC currently does not support cluster compute quadruple extra large (cc1.4xlarge) instances. Thus you cannot specify the cc1.4xlarge instance type for nodes of a job flow launched in a Amazon VPC.

  • EmrManagedMasterSecurityGroup (string) --

    The identifier of the Amazon EC2 security group for the master node.

  • EmrManagedSlaveSecurityGroup (string) --

    The identifier of the Amazon EC2 security group for the slave nodes.

  • ServiceAccessSecurityGroup (string) --

    The identifier of the Amazon EC2 security group for the Amazon EMR service to access clusters in VPC private subnets.

  • AdditionalMasterSecurityGroups (list) --

    A list of additional Amazon EC2 security group IDs for the master node.

    • (string) --

  • AdditionalSlaveSecurityGroups (list) --

    A list of additional Amazon EC2 security group IDs for the slave nodes.

    • (string) --

type Steps

list

param Steps

A list of steps to be executed by the job flow.

  • (dict) --

    Specification of a job flow step.

    • Name (string) -- [REQUIRED]

      The name of the job flow step.

    • ActionOnFailure (string) --

      The action to take if the job flow step fails.

    • HadoopJarStep (dict) -- [REQUIRED]

      The JAR file used for the job flow step.

      • Properties (list) --

        A list of Java properties that are set when the step runs. You can use these properties to pass key value pairs to your main function.

        • (dict) --

          A key value pair.

          • Key (string) --

            The unique identifier of a key value pair.

          • Value (string) --

            The value part of the identified key.

      • Jar (string) -- [REQUIRED]

        A path to a JAR file run during the step.

      • MainClass (string) --

        The name of the main class in the specified Java file. If not specified, the JAR file should specify a Main-Class in its manifest file.

      • Args (list) --

        A list of command line arguments passed to the JAR file's main function when executed.

        • (string) --

type BootstrapActions

list

param BootstrapActions

A list of bootstrap actions that will be run before Hadoop is started on the cluster nodes.

  • (dict) --

    Configuration of a bootstrap action.

    • Name (string) -- [REQUIRED]

      The name of the bootstrap action.

    • ScriptBootstrapAction (dict) -- [REQUIRED]

      The script run by the bootstrap action.

      • Path (string) -- [REQUIRED]

        Location of the script to run during a bootstrap action. Can be either a location in Amazon S3 or on a local file system.

      • Args (list) --

        A list of command line arguments to pass to the bootstrap action script.

        • (string) --

type SupportedProducts

list

param SupportedProducts

Note

For Amazon EMR releases 3.x and 2.x. For Amazon EMR releases 4.x and greater, use Applications.

A list of strings that indicates third-party software to use with the job flow. For more information, go to Use Third Party Applications with Amazon EMR . Currently supported values are:

  • "mapr-m3" - launch the job flow using MapR M3 Edition.

  • "mapr-m5" - launch the job flow using MapR M5 Edition.

  • (string) --

type NewSupportedProducts

list

param NewSupportedProducts

Note

For Amazon EMR releases 3.x and 2.x. For Amazon EMR releases 4.x and greater, use Applications.

A list of strings that indicates third-party software to use with the job flow that accepts a user argument list. EMR accepts and forwards the argument list to the corresponding installation script as bootstrap action arguments. For more information, see Launch a Job Flow on the MapR Distribution for Hadoop . Currently supported values are:

  • "mapr-m3" - launch the cluster using MapR M3 Edition.

  • "mapr-m5" - launch the cluster using MapR M5 Edition.

  • "mapr" with the user arguments specifying "--edition,m3" or "--edition,m5" - launch the job flow using MapR M3 or M5 Edition respectively.

  • "mapr-m7" - launch the cluster using MapR M7 Edition.

  • "hunk" - launch the cluster with the Hunk Big Data Analtics Platform.

  • "hue"- launch the cluster with Hue installed.

  • "spark" - launch the cluster with Apache Spark installed.

  • "ganglia" - launch the cluster with the Ganglia Monitoring System installed.

  • (dict) --

    The list of supported product configurations which allow user-supplied arguments. EMR accepts these arguments and forwards them to the corresponding installation script as bootstrap action arguments.

    • Name (string) --

      The name of the product configuration.

    • Args (list) --

      The list of user-supplied arguments.

      • (string) --

type Applications

list

param Applications

Note

Amazon EMR releases 4.x or later.

A list of applications for the cluster. Valid values are: "Hadoop", "Hive", "Mahout", "Pig", and "Spark." They are case insensitive.

  • (dict) --

    An application is any Amazon or third-party software that you can add to the cluster. This structure contains a list of strings that indicates the software to use with the cluster and accepts a user argument list. Amazon EMR accepts and forwards the argument list to the corresponding installation script as bootstrap action argument. For more information, see Launch a Job Flow on the MapR Distribution for Hadoop . Currently supported values are:

    • "mapr-m3" - launch the job flow using MapR M3 Edition.

    • "mapr-m5" - launch the job flow using MapR M5 Edition.

    • "mapr" with the user arguments specifying "--edition,m3" or "--edition,m5" - launch the job flow using MapR M3 or M5 Edition, respectively.

    Note

    In Amazon EMR releases 4.0 and greater, the only accepted parameter is the application name. To pass arguments to applications, you supply a configuration for each application.

    • Name (string) --

      The name of the application.

    • Version (string) --

      The version of the application.

    • Args (list) --

      Arguments for Amazon EMR to pass to the application.

      • (string) --

    • AdditionalInfo (dict) --

      This option is for advanced users only. This is meta information about third-party applications that third-party vendors use for testing purposes.

      • (string) --

        • (string) --

type Configurations

list

param Configurations

Note

Amazon EMR releases 4.x or later.

The list of configurations supplied for the EMR cluster you are creating.

  • (dict) --

    Note

    Amazon EMR releases 4.x or later.

    Specifies a hardware and software configuration of the EMR cluster. This includes configurations for applications and software bundled with Amazon EMR. The Configuration object is a JSON object which is defined by a classification and a set of properties. Configurations can be nested, so a configuration may have its own Configuration objects listed.

    • Classification (string) --

      The classification of a configuration. For more information see, Amazon EMR Configurations .

    • Configurations (list) --

      A list of configurations you apply to this configuration object.

    • Properties (dict) --

      A set of properties supplied to the Configuration object.

      • (string) --

        • (string) --

type VisibleToAllUsers

boolean

param VisibleToAllUsers

Whether the job flow is visible to all IAM users of the AWS account associated with the job flow. If this value is set to true , all IAM users of that AWS account can view and (if they have the proper policy permissions set) manage the job flow. If it is set to false , only the IAM user that created the job flow can view and manage it.

type JobFlowRole

string

param JobFlowRole

Also called instance profile and EC2 role. An IAM role for an EMR cluster. The EC2 instances of the cluster assume this role. The default role is EMR_EC2_DefaultRole . In order to use the default role, you must have already created it using the CLI or console.

type ServiceRole

string

param ServiceRole

The IAM role that will be assumed by the Amazon EMR service to access AWS resources on your behalf.

type Tags

list

param Tags

A list of tags to associate with a cluster and propagate to Amazon EC2 instances.

  • (dict) --

    A key/value pair containing user-defined metadata that you can associate with an Amazon EMR resource. Tags make it easier to associate clusters in various ways, such as grouping clusters to track your Amazon EMR resource allocation costs. For more information, see Tagging Amazon EMR Resources .

rtype

dict

returns

Response Syntax

{
    'JobFlowId': 'string'
}

Response Structure

  • (dict) --

    The result of the RunJobFlow operation.

    • JobFlowId (string) --

      An unique identifier for the job flow.