What are some best practices for creating user-friendly cloud IAM policies?

2 Use templates and variables

Another way to create user-friendly cloud IAM policies is to use templates and variables to simplify and standardize your policy creation and maintenance. Templates are predefined policy statements that you can reuse and customize for different scenarios, such as granting access to a specific resource type, region, or action. Variables are placeholders that you can replace with dynamic values, such as the user name, account ID, or resource ARN. For example, you can use a template like this to grant read-only access to a resource:

{
  "Effect": "Allow",
  "Action": [
    "resource:Describe*",
    "resource:Get*",
    "resource:List*"
  ],
  "Resource": "${resource_arn}"
}        

And then use a variable like this to specify the resource ARN: resource_arn = "arn:aws:resource:us-east-1:123456789012:example"

3 Use conditions and context

A third way to create user-friendly cloud IAM policies is to use conditions and context to add flexibility and granularity to your policy decisions. Conditions are optional elements that you can add to your policy statements to specify additional requirements for granting or denying access, such as the time, date, IP address, or MFA status of the request. Context is the information that is available about the request and the environment, such as the user attributes, resource attributes, or session data. For example, you can use a condition like this to grant access only during business hours:

{
  "Effect": "Allow",
  "Action": "resource:DoSomething",
  "Resource": "*",
  "Condition": {
    "DateGreaterThan": {"aws:CurrentTime": "09:00"},
    "DateLessThan": {"aws:CurrentTime": "17:00"}
  }
}        

And you can use a context like this to grant access only to users with a specific attribute:

{
  "Effect": "Allow",
  "Action": "resource:DoSomething",
  "Resource": "*",
  "Condition": {
    "StringEquals": {"aws:PrincipalTag/department": "marketing"}
  }
}        

4 Use policy generators and validators

A fourth way to create user-friendly cloud IAM policies is to use policy generators and validators to help you create and verify your policy syntax and logic. Policy generators are tools that help you create policy statements based on your inputs, such as the resource, action, effect, and condition. Policy validators are tools that help you check your policy statements for errors, inconsistencies, or conflicts, such as typos, missing elements, or overlapping rules. For example, you can use the AWS Policy Generator to create policy statements for AWS services, and the AWS IAM Policy Simulator to test and debug your policy statements for AWS services.

5 Use feedback and documentation

A fifth way to create user-friendly cloud IAM policies is to use feedback and documentation to communicate and educate your users about your policy decisions and expectations. Feedback is the information that you provide to your users when they attempt to access a resource, such as an error message, a warning, or a confirmation. Documentation is the information that you provide to your users before they attempt to access a resource, such as a policy summary, a policy explanation, or a policy guide. For example, you can use feedback like this to inform your users why they are denied access: Access denied. You do not have permission to perform this action. Please contact your administrator for more information. And you can use documentation like this to explain your users what they need to do to access a resource: To access this resource, you need to have the editor role, use MFA, and connect from a trusted IP address.