What is IAM?
IAM stands for Identity and Access Management. It's the security guard of AWS — it controls who can do what with your resources. Without IAM, anyone with your AWS credentials could access everything, which is terrifying.
IAM lets you create users, groups, and roles, each with specific permissions. It's like giving different employees different keycards — the janitor can access the storage room, but the CEO can access the vault.
IAM Components
Users represent individual people or applications that need AWS access. Each user gets their own credentials and can be given specific permissions.
Groups are collections of users that share the same permissions. Instead of assigning permissions to each user individually, you put them in a group and set permissions once.
Roles are for granting temporary access. Instead of giving someone permanent credentials, a role provides temporary credentials that expire. EC2 instances, Lambda functions, and other AWS services use roles to access other services.
The Root Account
The root account is created when you first sign up for AWS. It has unlimited access to everything — it's the master key to your entire cloud kingdom. Guard it carefully.
Best practices: enable MFA on the root account, don't use it for daily tasks, and create an admin IAM user instead. Think of the root account as the nuclear launch codes — you only break the glass in emergencies.
IAM Best Practices
Never share your AWS credentials. Enable MFA on every user account. Use the principle of least privilege — give users only the permissions they need, nothing more. Rotate access keys regularly.
Use IAM roles for AWS services instead of embedding access keys in your code. If your Lambda function needs to access S3, give it a role — don't hard-code credentials. Hard-coded credentials are a security disaster waiting to happen.
IAM is Free
One of the best things about IAM: it's completely free. There are no charges for creating users, groups, roles, or policies. The only cost is the resources those users access.
This means there's no excuse not to use IAM properly. Set up your users, assign appropriate permissions, and enable MFA. It takes minutes and protects your AWS environment from unauthorized access.