Release: Amazon EC2 on 2011-12-30

Release Notes>Amazon EC2>Release: Amazon EC2 on 2011 12 30
Support for Amazon instance status checks and a new API version: 2011-12-15


Release Date: December 31, 2011 3:00 AM GMT
Latest Version: 2011-12-15
Latest WSDL:
Created On: January 6, 2012 12:32 AM GMT
Last Updated: January 31, 2012 2:12 AM GMT

New Features

New API Version With this release, Amazon EC2 has a new API version (2011-12-15). The WSDL is at To get the latest version of the API tools, go to Amazon EC2 API Tools.
Instance Status Checks With this release, you can use the DescribeInstanceStatus action to retrieve results of automated checks performed by Amazon EC2. These status checks detect problems that may impair an instance's ability to run your applications. You can use ReportInstanceStatus to send us feedback or report an inaccurate instance status.

Resolved Issues

Issue Resolution
n/a n/a

Version History

Release Date WDSL Description
2011-12-21 2011-12-01.ec2.wsdl Support for elastic network interfaces (ENIs) for EC2 instances running in Amazon Virtual Private Cloud (Amazon VPC)
2011-12-01 2011-11-01.ec2.wsdl Support for new choices of Reserved Instance offerings
2011-11-17 2011-11-01.ec2.wsdl Support for the DescribeInstanceStatus API
2011-10-11 2011-07-15.ec2.wsdl Support for EC2 Spot Instances in Amazon VPC
2011-09-15 2011-07-15.ec2.wsdl Support for EC2 VM Import CLI Updates
2011-08-24 2011-07-15.ec2.wsdl VM Import Support for Windows Server 2003 and VHD file format
2011-05-26 2011-05-15.ec2.wsdl Support for Amazon Spot Instances AZ Local Pricing Changes
2011-03-27 2011-02-28.ec2.wsdl Support for Dedicated Instances in a VPC
2011-03-15 2011-01-01.ec2.wsdl Support for Windows Server 2008 R2
2011-03-14 2011-01-01.ec2.wsdl Support for Amazon VPC Internet gateway and updated metadata
2010-12-16 2010-11-15.ec2.wsdl Support for Oracle enterprise applications on Amazon EC2
2010-12-15 2010-11-15.ec2.wsdl Support for VM Import
2010-12-02 2010-08-31.ec2.wsdl Support for Basic Monitoring for EC2 instances
2010-11-14 2010-08-31.ec2.wsdl Support for the new cluster GPU instance type (cg1.4xlarge)
2010-09-28 2010-08-31.ec2.wsdl Support for the AWS SDK for PHP
2010-09-19 2010-08-31.ec2.wsdl Support for tags, filters, idempotent RunInstance calls, and ImportKeyPair
2010-09-08 2010-06-15.ec2.wsdl Support for the new micro instance type
2010-09-02 2010-06-15.ec2.wsdl Support for AWS Identity and Access Management
2010-07-12 2010-06-15.ec2.wsdl Support for the new cluster compute instance type (cc1.4xlarge) and for specifying IP addresses in Amazon VPC
2010-06-14 2009-11-30.ec2.wsdl Support for Amazon CloudWatch monitoring for Amazon EBS volumes
2010-04-28 2009-11-30.ec2.wsdl Support for Asia Pacific (Singapore) Region
2010-03-22 2009-11-30.ec2.wsdl Support for the AWS SDK for Java
2010-02-22 2009-11-30.ec2.wsdl Support for the new High-Memory Extra Large instance type and for Reserved Instances with Windows
2009-12-14 2009-11-30.ec2.wsdl Support for Spot Instances

To view earlier EC2 Release Notes please see EC2.

Known Issues

Elastic Network Interfaces Warm attachment (when the instance is stopped) and Hot attachment (when the instance is running) of network interfaces to Windows Server 2003 instances isn't supported at this time.
Current Limitations for VM Import

Following are current limitations of VM Import:

  • The following types of images currently cannot be imported into Amazon EC2:
    • VMware Workstation VMDK images
    • Encrypted, compressed, or read-only images
    • Started or suspended images
    • Linked clones
    • Images with multiple virtual disks
  • When you import a disk image to an Amazon EC2 instance, the instance appears in the AWS Management Console before the conversion process finishes. To determine when the process is complete and the instance is available to use, use the ec2-describe-conversion-tasks command.
Current Limitations for Cluster Instances Following are current limitations of cluster compute and cluster GPU instances:
  • Only the US-East (Northern Virginia) Region supports cluster instances
  • Amazon Virtual Private Cloud is not supported
  • Amazon DevPay is not supported
Current Limitations for Cluster Placement Groups Following are current limitations of cluster placement groups:
  • Reserved Instances are not currently available within a cluster placement group
Current Limitations for Tags and Filters You currently cannot tag the following resources:
  • Elastic IP addresses
  • Key pairs
  • Placement groups
You can currently filter your resources in the AWS Management Console by tag, but not by the other filters that are available to use with Describe* actions through the command line tools or API.
Current Limitations for Micro Instances Following are current limitations of micro instances:
  • Amazon Virtual Private Cloud is not supported
  • Amazon Elastic MapReduce is not supported
  • Amazon DevPay is not supported
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: Setting the TCP_MAXSEG socket option on TCP sockets to certain values (e.g., 1500) causes the kernel to generate TCP Segmentation Offload (TSO) packets with invalid sizes that the NIC driver then drops. The impact is significantly lower network throughput. As a workaround, don't set this socket option and let the kernel use the default settings to handle segmentation and Path Maximum Transmission Unit (PMTU) discovery.
Query Version of ModifyInstanceAttribute The ModifyInstanceAttribute action currently does not allow you to modify the block device mapping for the instance.
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 Attaching 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 Request to Increase Amazon EC2 Instance Limit (
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