Release: Amazon EC2 on 2011-03-14
New Features
| Feature | Description |
|---|---|
| New API Version | With this release, Amazon VPC has a new API version (2011-01-01). The WSDL is at http://ec2.amazonaws.com/doc/2011-01-01/AmazonEC2.wsdl. To get the latest version of the API tools, go to Amazon EC2 API Tools. |
| New Amazon VPC Features | The main new features in this release are for Amazon VPC: Internet gateway, route tables, security groups, elastic IP addresses, network access control lists, and NAT instances. For more information about the features, see XREF TO VPC REL NOTES. |
| Changes to Security Groups | With
this release, all EC2 security groups now have AWS-assigned identifiers
(e.g., sg-1a2b3c4d). You can use either the friendly name or the ID
when working with EC2 security groups. The interface for adding rules to security groups in the AWS Management Console has been improved, including an easier way to specify ICMP types and codes. Also, several bugs have been fixed. Amazon
VPC now also has its own security groups. When you create a security
group, you now must specify whether it's an EC2 or VPC security group.
When you call |
| Changes to Elastic IP Addresses | Amazon
VPC now also has its own elastic IP addresses. When you allocate an
elastic IP address, you now must specify whether it's for use with
Amazon EC2 or Amazon VPC. When you call DescribeAddresses,
both your EC2 elastic IP addresses and VPC elastic IP addresses are
included in the results. There's a separate limit on the number of VPC
elastic IP addresses you can have. For more information, go to Elastic IP Addresses in the Amazon Virtual Private Cloud User Guide.
|
| Updated Metadata | With this release, new categories of metadata are available to instances (the new metadata version is 2011-01-01). For more information, go to Appendix B: Metadata Categories in the Amazon Elastic Compute Cloud User Guide. |
| Documentation | The Amazon VPC API reference and command line reference have been merged with the Amazon EC2 API reference and command line reference. |
Known Issues
| Issue | Description |
|---|---|
| Current Limitations for VM Import | Following are current limitations of VM Import:
|
| Current Limitations for Cluster Instances | Following are current limitations of cluster compute and cluster GPU instances:
|
| Current Limitations for Cluster Placement Groups | Following are current limitations of cluster placement groups:
|
| Current Limitations for Tags and Filters | You currently cannot tag the following resources:
Describe* actions through the command line tools or API. |
| Current Limitations for Micro Instances | Following are current limitations of micro instances:
|
| Instance Clock Drift | Some instances (Windows instances in particular) can experience a system clock drift. The issue appears to be more severe in t1.micro Windows instances that run CPU-intensive workloads. If your application is sensitive to time drift, consider using other instance types until a resolution is available. |
| 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 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 http://aws.amazon.com/contact-us/ec2-request. |
