What Is IAM?
AWS Identity and Access Management (IAM) is a web service that helps you securely control access to AWS resources for your users. You use IAM to control who can use your AWS resources (authentication) and what resources they can use and in what ways (authorization).
Video Introduction to AWS IAM
This short video (2:15) provides a brief introduction to AWS IAM.
IAM gives you the following features:
- Shared access to your AWS account
You can grant other people permission to administer and use resources in your AWS account without having to share your password or access key.
- Granular permissions
You can grant different permissions to different people for different resources. For example, you might allow some users complete access to Amazon Elastic Compute Cloud (Amazon EC2), Amazon Simple Storage Service (Amazon S3), Amazon DynamoDB, Amazon Redshift, and other AWS services. For other users, you can allow read-only access to just some S3 buckets, or permission to administer just some EC2 instances, or to access your billing information but nothing else.
- Secure access to AWS resources for applications that run on Amazon EC2
You can use IAM features to securely give applications that run on EC2 instances the credentials that they need in order to access other AWS resources, like S3 buckets and RDS or DynamoDB databases.
- Identity federation
You can allow users who already have passwords elsewhere—for example, in your corporate network or with an Internet identity provider—to get temporary access to your AWS account.
- Identity information for assurance
If you use AWS CloudTrail, you receive log records that include information about those who made requests for resources in your account. That information is based on IAM identities.
- PCI DSS Compliance
IAM supports the processing, storage, and transmission of credit card data by a merchant or service provider, and has been validated as being compliant with Payment Card Industry (PCI) Data Security Standard (DSS). For more information about PCI DSS, including how to request a copy of the AWS PCI Compliance Package, see PCI DSS Level 1.
- Integrated with many AWS services
For a list of AWS services that work with IAM, see AWS Services That Work with IAM.
- Eventually Consistent
IAM, like many other AWS services, is eventually consistent. IAM achieves high availability by replicating data across multiple servers within Amazon's data centers around the world. If a request to change some data is successful, the change is committed and safely stored. However, the change must be replicated across IAM, which can take some time. Such changes include creating or updating users, groups, roles, or policies. We recommend that you do not include such IAM changes in the critical, high-availability code paths of your application. Instead, make IAM changes in a separate initialization or setup routine that you run less frequently. Also, be sure to verify that the changes have been propagated before production workflows depend on them. For more information, see Changes that I make are not always immediately visible.
- Free to use
AWS Identity and Access Management is a feature of your AWS account offered at no additional charge. You will be charged only for use of other AWS products by your IAM users. For information about the pricing of other AWS products, see the Amazon Web Services pricing page.
AWS Security Token Service is an included feature of your AWS account offered at no additional charge. You are charged only for the use of other AWS services that are accessed by your AWS STS temporary security credentials. For information about the pricing of other AWS services, see the Amazon Web Services pricing page.
You can work with AWS Identity and Access Management in any of the following ways.
- AWS Management Console
The console is a browser-based interface to manage IAM and AWS resources. For more information about accessing IAM through the console, see The IAM Console and the Sign-in Page. For a tutorial that guides you through using the console, see Creating Your First IAM Admin User and Group.
- AWS Command Line Tools
You can use the AWS command line tools to issue commands at your system's command line to perform IAM and AWS tasks; this can be faster and more convenient than using the console. The command line tools are also useful if you want to build scripts that perform AWS tasks.
AWS provides two sets of command line tools: the AWS Command Line Interface (AWS CLI) and the AWS Tools for Windows PowerShell. For information about installing and using the AWS CLI, see the AWS Command Line Interface User Guide. For information about installing and using the Tools for Windows PowerShell, see the AWS Tools for Windows PowerShell User Guide.
- AWS SDKs
AWS provides SDKs (software development kits) that consist of libraries and sample code for various programming languages and platforms (Java, Python, Ruby, .NET, iOS, Android, etc.). The SDKs provide a convenient way to create programmatic access to IAM and AWS. For example, the SDKs take care of tasks such as cryptographically signing requests, managing errors, and retrying requests automatically. For information about the AWS SDKs, including how to download and install them, see the Tools for Amazon Web Services page.
- IAM HTTPS API
You can access IAM and AWS programmatically by using the IAM HTTPS API, which lets you issue HTTPS requests directly to the service. When you use the HTTPS API, you must include code to digitally sign requests using your credentials. For more information, see Calling the API by Making HTTP Query Requests and the IAM API Reference.