Planning and configuring instance fleets for your Amazon EMR cluster

The instance fleet configuration for Amazon EMR clusters lets you select a wide variety of provisioning options for Amazon EC2 instances, and helps you develop a flexible and elastic resourcing strategy for each node type in your cluster.

In an instance fleet configuration, you specify a target capacity for On-Demand Instances and Spot Instances within each fleet. When the cluster launches, Amazon EMR provisions instances until the targets are fulfilled. When Amazon EC2 reclaims a Spot Instance in a running cluster because of a price increase or instance failure, Amazon EMR tries to replace the instance with any of the instance types that you specify. This makes it easier to regain capacity during a spike in Spot pricing.

You can specify a maximum of five Amazon EC2 instance types per fleet for Amazon EMR to use when fulfilling the targets, or a maximum of 30 Amazon EC2 instance types per fleet when you create a cluster using the Amazon CLI or Amazon EMR API and an allocation strategy for On-Demand and Spot Instances.

You can also select multiple subnets for different Availability Zones. When Amazon EMR launches the cluster, it looks across those subnets to find the instances and purchasing options you specify. If Amazon EMR detects an Amazon large-scale event in one or more of the Availability Zones, Amazon EMR automatically attempts to route traffic away from the impacted Availability Zones and tries to launch new clusters that you create in alternate Availability Zones according to your selections. Note that cluster Availability Zone selection happens only at cluster creation. Existing cluster nodes are not automatically re-launched in a new Availability Zone in the event of an Availability Zone outage.

Considerations for working with instance fleets

Consider the following items when you use instance fleets with Amazon EMR.

Instance fleet options

Use the following guidelines to understand instance fleet options.

Setting target capacities

Specify the target capacities you want for the core fleet and task fleet. When you do, that determines the number of On-Demand Instances and Spot Instances that Amazon EMR provisions. When you specify an instance, you decide how much each instance counts toward the target. When an On-Demand Instance is provisioned, it counts toward the On-Demand target. The same is true for Spot Instances. Unlike core and task fleets, the primary fleet is always one instance. Therefore, the target capacity for this fleet is always one.

When you use the console, the vCPUs of the Amazon EC2 instance type are used as the count for target capacities by default. You can change this to Generic units, and then specify the count for each EC2 instance type. When you use the Amazon CLI, you manually assign generic units for each instance type.

For each fleet, you specify up to five Amazon EC2 instance types. If you use an Allocation strategy for instance fleets and create a cluster using the Amazon CLI or the Amazon EMR API, you can specify up to 30 EC2 instance types per instance fleet. Amazon EMR chooses any combination of these EC2 instance types to fulfill your target capacities. Because Amazon EMR wants to fill target capacity completely, an overage might happen. For example, if there are two unfulfilled units, and Amazon EMR can only provision an instance with a count of five units, the instance still gets provisioned, meaning that the target capacity is exceeded by three units.

If you reduce the target capacity to resize a running cluster, Amazon EMR attempts to complete application tasks and terminates instances to meet the new target. For more information, see Terminate at task completion.

Launch options

For Spot Instances, you can specify a Maximum Spot price for each instance type in a fleet. You can set this price either as a percentage of the On-Demand price, or as a specific dollar amount. Amazon EMR provisions Spot Instances if the current Spot price in an Availability Zone is below your maximum Spot price. You pay the Spot price, not necessarily the maximum Spot price.

Available in Amazon EMR 5.12.1 and later, you have the option to launch Spot and On-Demand Instance fleets with optimized capacity allocation. This allocation strategy option can be set in the old Amazon Web Services Management Console or using the API RunJobFlow. Note that you can't customize allocation strategy in the new console. Using the allocation strategy option requires additional service role permissions. If you use the default Amazon EMR service role and managed policy (EMR_DefaultRole and AmazonEMRServicePolicy_v2) for the cluster, the permissions for the allocation strategy option are already included. If you're not using the default Amazon EMR service role and managed policy, you must add them to use this option. See Service role for Amazon EMR (EMR role).

For more information about Spot Instances, see Spot Instances in the Amazon EC2 User Guide. For more information about On-Demand Instances, see On-Demand Instances in the Amazon EC2 User Guide.

If you choose to launch On-Demand Instance fleets with the lowest-price allocation strategy, you have the option to use capacity reservations. Capacity reservation options can be set using the Amazon EMR API RunJobFlow. Capacity reservations require additional service role permissions which you must add to use these options. See Allocation strategy permissions. Note that you can't customize capacity reservations in the new console.

Multiple subnet (Availability Zones) options

When you use instance fleets, you can specify multiple Amazon EC2 subnets within a VPC, each corresponding to a different Availability Zone. If you use EC2-Classic, you specify Availability Zones explicitly. Amazon EMR identifies the best Availability Zone to launch instances according to your fleet specifications. Instances are always provisioned in only one Availability Zone. You can select private subnets or public subnets, but you can't mix the two, and the subnets you specify must be within the same VPC.

Master node configuration

Because the primary instance fleet is only a single instance, its configuration is slightly different from core and task instance fleets. You only select either On-Demand or Spot for the primary instance fleet because it consists of only one instance. If you use the console to create the instance fleet, the target capacity for the purchasing option you select is set to 1. If you use the Amazon CLI, always set either TargetSpotCapacity or TargetOnDemandCapacity to 1 as appropriate. You can still choose up to five instance types for the primary instance fleet (or a maximum of 30 when you use the allocation strategy option for On-Demand or Spot Instances). However, unlike core and task instance fleets, where Amazon EMR might provision multiple instances of different types, Amazon EMR selects a single instance type to provision for the primary instance fleet.

Allocation strategy for instance fleets

With Amazon EMR versions 5.12.1 and later, you can use the allocation strategy option with On-Demand and Spot Instances for each cluster node. When you create a cluster using the Amazon CLI, Amazon EMR API, or Amazon EMR console with an allocation strategy, you can specify up to 30 Amazon EC2 instance types per fleet. With the default Amazon EMR cluster instance fleet configuration, you can have up to 5 instance types per fleet. We recommend that you use the allocation strategy option for faster cluster provisioning, more accurate Spot Instance allocation, and fewer Spot Instance interruptions.

Allocation strategy with On-Demand Instances

The following allocation strategies are available for your On-Demand Instances:

Allocation strategy with Spot Instances

For Spot Instances you can choose from one of the following allocation strategies:

Allocation strategy permissions

The allocation strategy option requires several IAM permissions that are automatically included in the default Amazon EMR service role and Amazon EMR managed policy (EMR_DefaultRole and AmazonEMRServicePolicy_v2). If you use a custom service role or managed policy for your cluster, you must add these permissions before you create the cluster. For more information, see Allocation strategy permissions.

Optional On-Demand Capacity Reservations (ODCRs) are available when you use the On-Demand allocation strategy option. Capacity reservation options let you specify a preference for using reserved capacity first for Amazon EMR clusters. You can use this to ensure that your critical workloads use the capacity you have already reserved using open or targeted ODCRs. For non-critical workloads, the capacity reservation preferences let you specify whether reserved capacity should be consumed.

Capacity reservations can only be used by instances that match their attributes (instance type, platform, and Availability Zone). By default, open capacity reservations are automatically used by Amazon EMR when provisioning On-Demand Instances that match the instance attributes. If you don't have any running instances that match the attributes of the capacity reservations, they remain unused until you launch an instance matching their attributes. If you don't want to use any capacity reservations when launching your cluster, you must set capacity reservation preference to none in launch options.

However, you can also target a capacity reservation for specific workflows. This enables you to explicitly control which instances are allowed to run in that reserved capacity. For more information about On-Demand capacity reservations, see Use capacity reservations with instance fleets in Amazon EMR.

Required IAM permissions for an allocation strategy

Your Service role for Amazon EMR (EMR role) requires additional permissions to create a cluster that uses the allocation strategy option for On-Demand or Spot Instance fleets.

We automatically include these permissions in the default Amazon EMR service role EMR_DefaultRole and the Amazon EMR managed policy AmazonEMRServicePolicy_v2.

If you use a custom service role or managed policy for your cluster, you must add the following permissions:

{
	"Version": "2012-10-17",
	"Statement": [
		{
			"Effect": "Allow",
			"Action": [
				"ec2:DeleteLaunchTemplate",
				"ec2:CreateLaunchTemplate",
				"ec2:DescribeLaunchTemplates",
				"ec2:CreateLaunchTemplateVersion",
				"ec2:CreateFleet"
			],
			"Resource": "*"
		}
}

The following service role permissions are required to create a cluster that uses open or targeted capacity reservations. You must include these permissions in addition to the permissions required for using the allocation strategy option.

{
    "Version": "2012-10-17",
    "Statement": [
        {
            "Effect": "Allow",
            "Action": [
                "ec2:DescribeCapacityReservations",
                "ec2:DescribeLaunchTemplateVersions",
                "ec2:DeleteLaunchTemplateVersions"
            ],
            "Resource": "*"
        }
    ]
}

{
    "Version": "2012-10-17",
    "Statement": [
        {
            "Effect": "Allow",
            "Action": [
                "ec2:DescribeCapacityReservations",
                "ec2:DescribeLaunchTemplateVersions",
                "ec2:DeleteLaunchTemplateVersions",
                "resource-groups:ListGroupResources"
            ],
            "Resource": "*"
        }
    ]
}

Configure instance fleets for your cluster

Examples: Creating a cluster with the instance fleets configuration

The following examples demonstrate create-cluster commands with a variety of options that you can combine.

aws emr create-cluster --release-label emr-5.3.1 --service-role EMR_DefaultRole \
  --ec2-attributes InstanceProfile=EMR_EC2_DefaultRole \
  --instance-fleets \
    InstanceFleetType=MASTER,TargetOnDemandCapacity=1,InstanceTypeConfigs=['{InstanceType=m5.xlarge}'] \
    InstanceFleetType=CORE,TargetOnDemandCapacity=1,InstanceTypeConfigs=['{InstanceType=m5.xlarge}']

aws emr create-cluster --release-label emr-5.3.1 --service-role EMR_DefaultRole \
  --ec2-attributes InstanceProfile=EMR_EC2_DefaultRole \
  --instance-fleets \
    InstanceFleetType=MASTER,TargetSpotCapacity=1,\
InstanceTypeConfigs=['{InstanceType=m5.xlarge,BidPrice=0.5}'] \
    InstanceFleetType=CORE,TargetSpotCapacity=1,\
InstanceTypeConfigs=['{InstanceType=m5.xlarge,BidPrice=0.5}']

aws emr create-cluster --release-label emr-5.3.1 --service-role EMR_DefaultRole \
  --ec2-attributes InstanceProfile=EMR_EC2_DefaultRole,SubnetIds=['subnet-ab12345c'] \
  --instance-fleets \
    InstanceFleetType=MASTER,TargetOnDemandCapacity=1,\
InstanceTypeConfigs=['{InstanceType=m5.xlarge}'] \
    InstanceFleetType=CORE,TargetOnDemandCapacity=2,TargetSpotCapacity=6,\
InstanceTypeConfigs=['{InstanceType=m5.xlarge,BidPrice=0.5,WeightedCapacity=2}']

aws emr create-cluster --release-label emr-5.3.1 --service-role EMR_DefaultRole \
  --ec2-attributes InstanceProfile=EMR_EC2_DefaultRole,SubnetIds=['subnet-ab12345c','subnet-de67890f'] \
  --instance-fleets \
    InstanceFleetType=MASTER,TargetOnDemandCapacity=1,\
InstanceTypeConfigs=['{InstanceType=m5.xlarge}'] \
    InstanceFleetType=CORE,TargetSpotCapacity=11,\
InstanceTypeConfigs=['{InstanceType=m5.xlarge,BidPrice=0.5,WeightedCapacity=3}',\
'{InstanceType=m4.2xlarge,BidPrice=0.9,WeightedCapacity=5}'],\
LaunchSpecifications={SpotSpecification='{TimeoutDurationMinutes=120,TimeoutAction=SWITCH_TO_ON_DEMAND}'}

aws emr create-cluster --release-label emr-5.3.1 --service-role EMR_DefaultRole \
  --ec2-attributes InstanceProfile=EMR_EC2_DefaultRole,SubnetIds=['subnet-ab12345c','subnet-de67890f'] \
  --instance-fleets \
    InstanceFleetType=MASTER,TargetOnDemandCapacity=1,InstanceTypeConfigs=['{InstanceType=m5.xlarge}'] \
    InstanceFleetType=CORE,TargetOnDemandCapacity=8,TargetSpotCapacity=6,\
InstanceTypeConfigs=['{InstanceType=m5.xlarge,BidPrice=0.5,WeightedCapacity=3}',\
'{InstanceType=m4.2xlarge,BidPrice=0.9,WeightedCapacity=5}'],\
LaunchSpecifications={SpotSpecification='{TimeoutDurationMinutes=120,TimeoutAction=SWITCH_TO_ON_DEMAND}'} \
    InstanceFleetType=TASK,TargetOnDemandCapacity=3,TargetSpotCapacity=3,\
InstanceTypeConfigs=['{InstanceType=m5.xlarge,BidPrice=0.5,WeightedCapacity=3}']

aws emr create-cluster --release-label Amazon EMR 5.3.1 --service-role EMR_DefaultRole \ 
  --ec2-attributes InstanceProfile=EMR_EC2_DefaultRole \
  --instance-fleets \
    InstanceFleetType=MASTER,TargetSpotCapacity=1,\
LaunchSpecifications={SpotSpecification='{TimeoutDurationMinutes=60,TimeoutAction=TERMINATE_CLUSTER}'},\
InstanceTypeConfigs=['{InstanceType=m5.xlarge,BidPrice=0.5,\
EbsConfiguration={EbsOptimized=true,EbsBlockDeviceConfigs=[{VolumeSpecification={VolumeType=gp2,\
SizeIn GB=100}},{VolumeSpecification={VolumeType=io1,SizeInGB=100,Iop s=100},VolumesPerInstance=4}]}}']		

aws emr create-cluster --release-label Amazon EMR 5.3.1 --service-role EMR_DefaultRole \
  --ec2-attributes InstanceProfile=EMR_EC2_DefaultRole \
  --instance-fleets \
    InstanceFleetType=MASTER,TargetOnDemandCapacity=1,\
InstanceTypeConfigs=['{InstanceType=m5.xlarge,CustomAmiId=ami-123456},{InstanceType=m6g.xlarge, CustomAmiId=ami-234567}'] \ 
    InstanceFleetType=CORE,TargetOnDemandCapacity=1,\
InstanceTypeConfigs=['{InstanceType=m5.xlarge,CustomAmiId=ami-123456},{InstanceType=m6g.xlarge, CustomAmiId=ami-234567}']

aws emr add-instance-fleet --cluster-id j-123456 --release-label Amazon EMR 5.3.1 \
  --service-role EMR_DefaultRole \
  --ec2-attributes InstanceProfile=EMR_EC2_DefaultRole \
  --instance-fleet \
    InstanceFleetType=Task,TargetSpotCapacity=1,\
InstanceTypeConfigs=['{InstanceType=m5.xlarge,CustomAmiId=ami-123456}',\
'{InstanceType=m6g.xlarge,CustomAmiId=ami-234567}']

aws emr create-cluster --release-label emr-5.30.0 --service-role EMR_DefaultRole \
--ec2-attributes InstanceProfile=EMR_EC2_DefaultRole \
--instance-fleets file://my-fleet-config.json

[
    {
        "Name": "Masterfleet",
        "InstanceFleetType": "MASTER",
        "TargetSpotCapacity": 1,
        "LaunchSpecifications": {
            "SpotSpecification": {
                "TimeoutDurationMinutes": 120,
                "TimeoutAction": "SWITCH_TO_ON_DEMAND"
            }
        },
        "InstanceTypeConfigs": [
            {
                "InstanceType": "m5.xlarge",
                "BidPrice": "0.89"
            }
        ]
    },
    {
        "Name": "Corefleet",
        "InstanceFleetType": "CORE",
        "TargetSpotCapacity": 1,
        "TargetOnDemandCapacity": 1,
        "LaunchSpecifications": {
          "OnDemandSpecification": {
            "AllocationStrategy": "lowest-price",
            "CapacityReservationOptions": 
            {
                "UsageStrategy": "use-capacity-reservations-first",
                "CapacityReservationResourceGroupArn": "String"
            }
        },
            "SpotSpecification": {
                "AllocationStrategy": "capacity-optimized",
                "TimeoutDurationMinutes": 120,
                "TimeoutAction": "TERMINATE_CLUSTER"
            }
        },
        "InstanceTypeConfigs": [
            {
                "InstanceType": "m5.xlarge",
                "BidPriceAsPercentageOfOnDemandPrice": 100
            }
        ]
    },
    {
        "Name": "Taskfleet",
        "InstanceFleetType": "TASK",
        "TargetSpotCapacity": 1,
        "LaunchSpecifications": {
          "OnDemandSpecification": {
            "AllocationStrategy": "lowest-price",
            "CapacityReservationOptions": 
            {
                "CapacityReservationPreference": "none"
            }
        },
            "SpotSpecification": {
                "TimeoutDurationMinutes": 120,
                "TimeoutAction": "TERMINATE_CLUSTER"
            }
        },
        "InstanceTypeConfigs": [
            {
                "InstanceType": "m5.xlarge",
                "BidPrice": "0.89"
            }
        ]
    }
]

Modify target capacities for an instance fleet

Use the modify-instance-fleet command to specify new target capacities for an instance fleet. You must specify the cluster ID and the instance fleet ID. Use the list-instance-fleets command to retrieve instance fleet IDs.

aws emr modify-instance-fleet --cluster-id <cluster-id> \
  --instance-fleet \
    InstanceFleetId='<instance-fleet-id>',TargetOnDemandCapacity=1,TargetSpotCapacity=1			

Add a task instance fleet to a cluster

If a cluster has only primary and core instance fleets, you can use the add-instance-fleet command to add a task instance fleet. You can only use this to add task instance fleets.

aws emr add-instance-fleet --cluster-id <cluster-id> 
  --instance-fleet \
    InstanceFleetType=TASK,TargetSpotCapacity=1,\
LaunchSpecifications={SpotSpecification='{TimeoutDurationMinutes=20,TimeoutAction=TERMINATE_CLUSTER}'},\
InstanceTypeConfigs=['{InstanceType=m5.xlarge,BidPrice=0.5}']				

Get configuration details of instance fleets in a cluster

Use the list-instance-fleets command to get configuration details of the instance fleets in a cluster. The command takes a cluster ID as input. The following example demonstrates the command and its output for a cluster that contains a primary task instance group and a core task instance group. For full response syntax, see ListInstanceFleets in the Amazon EMR API Reference.

list-instance-fleets --cluster-id <cluster-id>			

{
    "InstanceFleets": [
        {
            "Status": {
                "Timeline": {
                    "ReadyDateTime": 1488759094.637,
                    "CreationDateTime": 1488758719.817
                },
                "State": "RUNNING",
                "StateChangeReason": {
                    "Message": ""
                }
            },
            "ProvisionedSpotCapacity": 6,
            "Name": "CORE",
            "InstanceFleetType": "CORE",
            "LaunchSpecifications": {
                "SpotSpecification": {
                    "TimeoutDurationMinutes": 60,
                    "TimeoutAction": "TERMINATE_CLUSTER"
                }
            },
            "ProvisionedOnDemandCapacity": 2,
            "InstanceTypeSpecifications": [
                {
                    "BidPrice": "0.5",
                    "InstanceType": "m5.xlarge",
                    "WeightedCapacity": 2
                }
            ],
            "Id": "if-1ABC2DEFGHIJ3"
        },
        {
            "Status": {
                "Timeline": {
                    "ReadyDateTime": 1488759058.598,
                    "CreationDateTime": 1488758719.811
                },
                "State": "RUNNING",
                "StateChangeReason": {
                    "Message": ""
                }
            },
            "ProvisionedSpotCapacity": 0,
            "Name": "MASTER",
            "InstanceFleetType": "MASTER",
            "ProvisionedOnDemandCapacity": 1,
            "InstanceTypeSpecifications": [
                {
                    "BidPriceAsPercentageOfOnDemandPrice": 100.0,
                    "InstanceType": "m5.xlarge",
                    "WeightedCapacity": 1
                }
            ],
           "Id": "if-2ABC4DEFGHIJ4"
        }
    ]
}