Amazon Web Services (AWS) continued its full court press on cloud computing on Monday, launching a host of new features in its EC2 cloud platform that will give integrators and developers more control in the cloud.
According to a blog post by AWS evangelist Jeff Barr, resource tagging lets users tag EC2 resources, along with other shared resources, using up to 10 key-value pairs per resource. Each tag consists of a key of up to 128 characters and a value of up to 256 characters and is stored in the AWS cloud as part of a user's AWS account. The tags, Amazon noted, are private to that account. Resourced that can be tagged include EC2 instances, Amazon Machine Images, EBS Volumes, EBS snapshots, and Amazon VPC resources like VPCs, subnets, connections and gateways. Resources can be tagged right after they're created, Barr wrote in a blog post.
Tags can also be manipulated using a trio of new API calls: CreateTags, which lets users tag one or more EC2 resources with one or more tags; DescribeTags, which gives users the tag associated with one or more resources, which can filter by resource identifier, type, key or value; and DeleteTags, which lets users delete a set of tags from a set of resources.
"You can create and delete tags using the AWS Management Console. You can view the tags associated with any resource, you can use a tag as a column in any resource list, and you can filter any view by tag," Barr wrote.
Another new feature, idempotent instance creation, gives users better control over instance creation, lets users create just one instance and not accidentally create and pay for two instances when an instance times out or when trying to determine if a request was successful or not.
"To provide you with better control in this situation, we've just a released a somewhat esoteric (yet very useful) feature called idempotent instance creation," Barr wrote. "Performing an idempotent operation more than once yields the same result as applying it just once. Washing your dog is idempotent (you always end up with a clean dog); feeding your dog is not (your dog will get fat)."
EC2 RunInstances now supports idempotency, which will help users build management and control applications that are more robust, Amazon said.
Amazon has also added new filtering functionality into EC2, which lets users specify filters when they call the EC2 Describe functions. Users can provide one or more filters as part of a call to a Describe function and each filter consists of a case-sensitive name and a value. Multiple filters can be combined and filters are also supported by EC2 command-line tools.
Lastly, AWS added the ability for users to import their own RSA keypair for use with EC2 instances. Letting users leverage their own keypair ensures trust by giving better control over keys; and security, as users can be confident that a private key was never transmitted over the wire. It also lets users use the same public keys across multiple AWS regions, Barr wrote.