Release: Amazon EC2 on 2010-09-02

Release Notes>Amazon EC2>Release: Amazon EC2 on 2010 09 02
Added support for AWS Identity and Access Management (IAM).


Submitted By: cheriaws
Release Date: September 2, 2010 12:00 AM GMT
Latest Version: 2010-06-15
Latest WSDL:
Created On: August 20, 2010 11:49 PM GMT
Last Updated: September 3, 2010 3:42 AM GMT

New Features

Support for AWS IAM Amazon EC2 now supports the AWS Identity and Access Management (IAM) web service that enables Amazon Web Services (AWS) customers to have one AWS Account and create Users for that account. Typically, an organization has an AWS Account and the organization creates Users (for each employee) so they can access AWS resources without having to have their own AWS Accounts. With IAM, you can centrally manage Users, security credentials (such as access keys), and permissions so that Users can only access those AWS resources they need to do their jobs.

For more information about IAM, go to

Known Issues

Current Limitations for Cluster Compute Instances Following are current limitations of cluster compute instances:
  • They support Linux/UNIX operating systems, but currently not Microsoft Windows Server
  • They are available only in the US-East (Northern Virginia) Region
  • Spot Instance requests for cluster compute instances are not supported
  • They are not available for use with Amazon Virtual Private Cloud
  • They are not available for use with Amazon DevPay
Current Limitations for Cluster Placement Groups Following are current limitations of cluster placement groups:
  • You can't currently use Auto Scaling to launch cluster compute instances into a cluster placement group
  • Reserved Instances are not currently available within a cluster placement group
Setting the TCP_MAXSEG Socket Option The 2.6.18-164.15.1 kernel used in the CentOS 5.4 reference AMI (ami-7ea24a17) contains a known issue where setting the TCP_MAXSEG socket option on TCP sockets to certain values (known values include 1500) causes the kernel to generate TCP Segmentation Offload (TSO) packets of invalid size that are then dropped by the NIC driver, resulting in very low network throughput. Don't set this socket option and let the kernel handle segmentation and Path Maximum Transmission Unit (PMTU) discovery using the default settings.
Query Version of ModifyInstanceAttribute The Query API ModifyInstanceAttribute request does not allow you to modify the block-device-mappings, and you can't modify the user-data attribute if it already contains data.
Paid AMIs Backed by Amazon EBS Amazon EBS-backed AMIs are not currently supported by Amazon DevPay.
Windows AMI launch times Windows AMIs take longer to launch than Linux/UNIX instances due to larger AMI sizes and multiple reboots.
Windows AMI sizes Installing software on Amazon S3-backed Windows AMIs can cause them to become large and easily reach the 10 GB limit. Before bundling, check the size of the C:\ volume.
Limitation on drive mapping There are limitations on devices available for storage attachment. For more information, go to How to Attach the Volume to an Instance in the Amazon Elastic Compute Cloud User Guide.
Instance limit New AWS accounts are limited to a maximum of 20 concurrent instances, but many of our customers use hundreds or thousands of instances. If you need a higher limit, go to
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