Using Amazon EC2 launch templates with AWS PCS - AWS PCS
Overview

Using Amazon EC2 launch templates with AWS PCS

In Amazon EC2, a launch template can store a set of preferences so that you don't have to specify them individually when you launch instances. AWS PCS incorporates launch templates as a flexible way to configure compute node groups. When you create a node group, you provide a launch template. AWS PCS creates a derived launch template from it that includes transformations to help ensure it works with the service.

Understanding what the options and considerations are when writing a custom launch template can help you write one for use with AWS PCS. For more information on launch templates, see Launching an Instance from a Launch an instance from a launch template in the Amazon EC2 User Guide.

Topics

Overview

There are over 30 parameters available you can include in an EC2 launch template, controlling many aspects of how instances are configured. Most are fully compatible with AWS PCS, but there are some exceptions.

The following parameters of EC2 Launch template will be ignored by AWS PCS as these properties have to be directly managed by the service:

  • Instance type/Specify instance type attributes (InstanceRequirements) – AWS PCS does not support attribute-based instance selection.

  • Instance type (InstanceType) – Specify instance types when you create a node group.

  • Advanced details/IAM instance profile (IamInstanceProfile) – You provide this when you create or update the node group.

  • Advanced details/Disable API termination (DisableApiTermination) – AWS PCS must control the lifecycle of node group instances it launches.

  • Advanced details/Disable API stop (DisableApiStop) – AWS PCS must control the lifecycle of node group instances it launches.

  • Advanced details/Stop – Hibernate behavior (HibernationOptions) – AWS PCS does not support instance hibernation.

  • Advanced details/Elastic GPU (ElasticGpuSpecifications) – Amazon Elastic Graphics reached end of life on January 8, 2024.

  • Advanced details/Elastic inference (ElasticInferenceAccelerators) – Amazon Elastic Inference is no longer available to new customers.

  • AAdvanced details/Specify CPU options/Threads per core (ThreadsPerCore) – AWS PCS sets the number of threads per core to 1.

These parameters have special requirements that support compatibility with AWS PCS:

  • User data(UserData) – This must be multi-part encoded. See Working with Amazon EC2 user data.

  • Application and OS Images(ImageId) – You can include this. However, if you specify an AMI ID when you create or update the node group, it will override the value in the launch template. The AMI you provide must be compatible with AWS PCS. For more information, see "Amazon Machine Images (AMIs) for AWS PCS.

  • Network settings/Firewall (security groups)(SecurityGroups) – A list of security group names can’t be set in an AWS PCS launch template. You can set a list of security group IDs (SecurityGroupIds), unless you define network interfaces in the launch template. Then, you must specify security group IDs for each interface. For more information, see Security groups in AWS PCS.

  • Network settings/Advanced network configuration(NetworkInterfaces) – If you use EC2 instances with a single network card, and don't require any specialized networking configuration, AWS PCS can configure instance networking for you. To configure multiple network cards or to enable Elastic Fabric Adapter on your instances, use NetworkInterfaces. Each network interface must have a list of security group IDs under Groups. For more information, see Multiple network interfaces in AWS PCS.

  • Advanced details/Capacity reservation(CapacityReservationSpecification) – This can be set, but cannot reference a specific CapacityReservationId when working with AWS PCS. You can, however, reference a capacity reservation group, where that group contains one or more capacity reservations. For more information, see Capacity Reservations in AWS PCS.