Simplifying Amazon EC2 instance type flexibility with new attribute-based instance type selection features

This blog is written by Rajesh Kesaraju, Sr. Solution Architect, EC2-Flexible Compute and Peter Manastyrny, Sr. Product Manager, EC2.

Today AWS is adding two new attributes for the attribute-based instance type selection (ABS) feature to make it even easier to create and manage instance type flexible configurations on Amazon EC2. The new network bandwidth attribute allows customers to request instances based on the network requirements of their workload. The new allowed instance types attribute is useful for workloads that have some instance type flexibility but still need more granular control over which instance types to run on.

The two new attributes are supported in EC2 Auto Scaling Groups (ASG), EC2 Fleet, Spot Fleet, and Spot Placement Score.

Before exploring the new attributes in detail, let us review the core ABS capability.

ABS refresher

ABS lets you express your instance type requirements as a set of attributes, such as vCPU, memory, and storage when provisioning EC2 instances with ASG, EC2 Fleet, or Spot Fleet. Your requirements are translated by ABS to all matching EC2 instance types, simplifying the creation and maintenance of instance type flexible configurations. ABS identifies the instance types based on attributes that you set in ASG, EC2 Fleet, or Spot Fleet configurations. When Amazon EC2 releases new instance types, ABS will automatically consider them for provisioning if they match the selected attributes, removing the need to update configurations to include new instance types.

ABS helps you to shift from an infrastructure-first to an application-first paradigm. ABS is ideal for workloads that need generic compute resources and do not necessarily require the hardware differentiation that the Amazon EC2 instance type portfolio delivers. By defining a set of compute attributes instead of specific instance types, you allow ABS to always consider the broadest and newest set of instance types that qualify for your workload. When you use EC2 Spot Instances to optimize your costs and save up to 90% compared to On-Demand prices, instance type diversification is the key to access the highest amount of Spot capacity. ABS provides an easy way to configure and maintain instance type flexible configurations to run fault-tolerant workloads on Spot Instances.

We recommend ABS as the default compute provisioning method for instance type flexible workloads including containerized apps, microservices, web applications, big data, and CI/CD.

Now, let us dive deep on the two new attributes: network bandwidth and allowed instance types.

How network bandwidth attribute for ABS works

Network bandwidth attribute allows customers with network-sensitive workloads to specify their network bandwidth requirements for compute infrastructure. Some of the workloads that depend on network bandwidth include video streaming, networking appliances (e.g., firewalls), and data processing workloads that require faster inter-node communication and high-volume data handling.

The network bandwidth attribute uses the same min/max format as other ABS attributes (e.g., vCPU count or memory) that assume a numeric value or range (e.g., min: ‘10’ or min: ‘15’; max: ‘40’). Note that setting the minimum network bandwidth does not guarantee that your instance will achieve that network bandwidth. ABS will identify instance types that support the specified minimum bandwidth, but the actual bandwidth of your instance might go below the specified minimum at times.

Two important things to remember when using the network bandwidth attribute are:

• ABS will only take burst bandwidth values into account when evaluating maximum values. When evaluating minimum values, only the baseline bandwidth will be considered.
  • For example, if you specify the minimum bandwidth as 10 Gbps, instances that have burst bandwidth of “up to 10 Gbps” will not be considered, as their baseline bandwidth is lower than the minimum requested value (e.g., m5.4xlarge is burstable up to 10 Gbps with a baseline bandwidth of 5 Gbps).
  • Alternatively, c5n.2xlarge, which is burstable up to 25 Gbps with a baseline bandwidth of 10 Gbps will be considered because its baseline bandwidth meets the minimum requested value.
• Our recommendation is to only set a value for maximum network bandwidth if you have specific requirements to restrict instances with higher bandwidth. That would help to ensure that ABS considers the broadest possible set of instance types to choose from.

Using the network bandwidth attribute in ASG

In this example, let us look at a high-performance computing (HPC) workload or similar network bandwidth sensitive workload that requires a high volume of inter-node communications. We use ABS to select instances that have at minimum 10 Gpbs of network bandwidth and at least 32 vCPUs and 64 GiB of memory.

To get started, you can create or update an ASG or EC2 Fleet set up with ABS configuration and specify the network bandwidth attribute.

The following example shows an ABS configuration with network bandwidth attribute set to a minimum of 10 Gbps. In this example, we do not set a maximum limit for network bandwidth. This is done to remain flexible and avoid restricting available instance type choices that meet our minimum network bandwidth requirement.

Create the following configuration file and name it: my_asg_network_bandwidth_configuration.json

{
    "AutoScalingGroupName": "network-bandwidth-based-instances-asg",
    "DesiredCapacityType": "units",
    "MixedInstancesPolicy": {
        "LaunchTemplate": {
            "LaunchTemplateSpecification": {
                "LaunchTemplateName": "LaunchTemplate-x86",
                "Version": "$Latest"
            },
            "Overrides": [
                {
                "InstanceRequirements": {
                    "VCpuCount": {"Min": 32},
                    "MemoryMiB": {"Min": 65536},
                    "NetworkBandwidthGbps": {"Min": 10} }
                 }
            ]
        },
        "InstancesDistribution": {
            "OnDemandPercentageAboveBaseCapacity": 30,
            "SpotAllocationStrategy": "capacity-optimized"
        }
    },
    "MinSize": 1,
    "MaxSize": 10,
    "DesiredCapacity":10,
    "VPCZoneIdentifier": "subnet-f76e208a, subnet-f76e208b, subnet-f76e208c"
}

Next, let us create an ASG using the following command:

my_asg_network_bandwidth_configuration.json file

aws autoscaling create-auto-scaling-group --cli-input-json file://my_asg_network_bandwidth_configuration.json

As a result, you have created an ASG that may include instance types m5.8xlarge, m5.12xlarge, m5.16xlarge, m5n.8xlarge, and c5.9xlarge, among others. The actual selection at the time of the request is made by capacity optimized Spot allocation strategy. If EC2 releases an instance type in the future that would satisfy the attributes provided in the request, that instance will also be automatically considered for provisioning.

Now let us focus our attention on another new attribute – allowed instance types.

How allowed instance types attribute works in ABS

As discussed earlier, ABS lets us provision compute infrastructure based on our application requirements instead of selecting specific EC2 instance types. Although this infrastructure agnostic approach is suitable for many workloads, some workloads, while having some instance type flexibility, still need to limit the selection to specific instance families, and/or generations due to reasons like licensing or compliance requirements, application performance benchmarking, and others. Furthermore, customers have asked us to provide the ability to restrict the auto-consideration of newly released instances types in their ABS configurations to meet their specific hardware qualification requirements before considering them for their workload. To provide this functionality, we added a new allowed instance types attribute to ABS.

The allowed instance types attribute allows ABS customers to narrow down the list of instance types that ABS considers for selection to a specific list of instances, families, or generations. It takes a comma separated list of specific instance types, instance families, and wildcard (*) patterns. Please note, that it does not use the full regular expression syntax.

For example, consider container-based web application that can only run on any 5^th generation instances from compute optimized (c), general purpose (m), or memory optimized (r) families. It can be specified as “AllowedInstanceTypes”: [“c5*”, “m5*”,”r5*”].

Another example could be to limit the ABS selection to only memory-optimized instances for big data Spark workloads. It can be specified as “AllowedInstanceTypes”: [“r6*”, “r5*”, “r4*”].

Note that you cannot use both the existing exclude instance types and the new allowed instance types attributes together, because it would lead to a validation error.

Using allowed instance types attribute in ASG

Let us look at the InstanceRequirements section of an ASG configuration file for a sample web application. The AllowedInstanceTypes attribute is configured as [“c5.*”, “m5.*”,”c4.*”, “m4.*”] which means that ABS will limit the instance type consideration set to any instance from 4^th and 5^th generation of c or m families. Additional attributes are defined to a minimum of 4 vCPUs and 16 GiB RAM and allow both Intel and AMD processors.

Create the following configuration file and name it: my_asg_allow_instance_types_configuration.json

{
    "AutoScalingGroupName": "allow-instance-types-based-instances-asg",
    "DesiredCapacityType": "units",
    "MixedInstancesPolicy": {
        "LaunchTemplate": {
            "LaunchTemplateSpecification": {
                "LaunchTemplateName": "LaunchTemplate-x86",
                "Version": "$Latest"
            },
            "Overrides": [
                {
                "InstanceRequirements": {
                    "VCpuCount": {"Min": 4},
                    "MemoryMiB": {"Min": 16384},
                    "CpuManufacturers": ["intel","amd"],
                    "AllowedInstanceTypes": ["c5.*", "m5.*","c4.*", "m4.*"] }
            }
            ]
        },
        "InstancesDistribution": {
            "OnDemandPercentageAboveBaseCapacity": 30,
            "SpotAllocationStrategy": "capacity-optimized"
        }
    },
    "MinSize": 1,
    "MaxSize": 10,
    "DesiredCapacity":10,
    "VPCZoneIdentifier": "subnet-f76e208a, subnet-f76e208b, subnet-f76e208c"
}

As a result, you have created an ASG that may include instance types like m5.xlarge, m5.2xlarge, c5.xlarge, and c5.2xlarge, among others. The actual selection at the time of the request is made by capacity optimized Spot allocation strategy. Please note that if EC2 will in the future release a new instance type which will satisfy the other attributes provided in the request, but will not be a member of 4^th or 5^th generation of m or c families specified in the allowed instance types attribute, the instance type will not be considered for provisioning.

As you can see, ABS considers a broad set of instance types for provisioning, however they all meet the compute attributes that are required for your workload.

Cleanup

To delete both ASGs and terminate all the instances, execute the following commands:

aws autoscaling delete-auto-scaling-group --auto-scaling-group-name network-bandwidth-based-instances-asg --force-delete

aws autoscaling delete-auto-scaling-group --auto-scaling-group-name allow-instance-types-based-instances-asg --force-delete

Conclusion

In this post, we explored the two new ABS attributes – network bandwidth and allowed instance types. Customers can use these attributes to select instances based on network bandwidth and to limit the set of instances that ABS selects from. The two new attributes, as well as the existing set of ABS attributes enable you to save time on creating and maintaining instance type flexible configurations and make it even easier to express the compute requirements of your workload.

ABS represents the paradigm shift in the way that our customers interact with compute, making it easier than ever to request diversified compute resources at scale. We recommend ABS as a tool to help you identify and access the largest amount of EC2 compute capacity for your instance type flexible workloads.