Concepts
Within AWS Identity and Access Management (IAM), policies are a crucial component for specifying permissions, allowing you to control access to AWS resources. There are two types of IAM policies that can be used to manage these permissions: AWS Managed Policies and Customer Managed Policies. Understanding the differences between them is vital for any aspiring AWS Certified Data Engineer.
AWS Managed Policies
AWS Managed Policies are pre-defined by AWS and provide a convenient way to assign permissions that are designed to support common, well-understood use cases. These policies are maintained and updated by AWS and are designed to provide the permissions necessary to perform tasks related to various AWS services without the need to write your own policy statements.
Pros:
- Simple and quick to implement.
- Regularly updated by AWS to incorporate new services and actions.
Cons:
- Less flexible as you cannot change the permissions defined by AWS.
- Can be overly permissive if the policy includes more permissions than necessary for a specific role or user.
Customer Managed Policies
Customer Managed Policies are created and managed by AWS customers. These policies provide a more granular level of control than AWS Managed Policies as they allow you to precisely define the permissions that are specific to your organization’s needs.
Pros:
- Fully customizable to fit the exact needs of your application or environment.
- You can version and roll back changes to policies.
Cons:
- Requires a deeper understanding of IAM policy language and AWS permissions.
- You are responsible for updating the policies to reflect new services or actions.
Comparing AWS Managed Policies and Customer Managed Policies
| Features | AWS Managed Policies | Customer Managed Policies |
|---|---|---|
| Who creates and manages? | Created by AWS | Created by the customer |
| Permissiveness | Can be broad | As specific as required |
| Customizability | None | Full |
| Versioning and Rollbacks | Not available | Available |
| Maintenance and Updates | Managed by AWS | Managed by customer |
| Usage Scope | Good for common use-case | Tailored for specific needs |
| Size Limits | Standard policy size limit | Size limit is larger |
Examples of When to Use Each Policy Type
Here are scenarios where each policy type may be especially useful:
1. AWS Managed Policy Use-Case: You need to quickly assign permissions to a new developer joining the team who will need general access to AWS Lambda functions. By attaching the AWSLambdaReadOnlyAccess managed policy, you can easily give that developer the ability to list and read information about Lambda functions without having to draft a policy from scratch.
2. Customer Managed Policy Use-Case: Your Data Engineering team requires specific access to an Amazon S3 bucket with the ability to read and write objects, list the bucket, and nothing else. You can create a Customer Managed Policy that specifies only those actions on the specific S3 resources the team needs to access, ensuring a minimized blast radius should any security issues arise.
Conclusion
To effectively manage permissions within AWS, it’s essential to understand the nuances between AWS Managed Policies and Customer Managed Policies. AWS Managed Policies are great for standard, well-understood tasks across AWS services, offering a straightforward solution with minimal setup. In contrast, Customer Managed Policies shine when precision and specificity are needed, allowing AWS Certified Data Engineers to sculpt the exact permissions required for the security and operational integrity of their systems.
As a Data Engineer preparing for the DEA-C01 exam, grasping the differences and applying the appropriate policy for the situation at hand is an essential skill, both for the certification and for real-world AWS resource management.
Answer the Questions in Comment Section
True or False: AWS managed policies are created and managed by AWS, while customer managed policies are created and managed by the users.
- Answer: True
AWS managed policies are pre-built by AWS for common use cases and provide a set of permissions that allow users to perform tasks related to a specific job function. Customer managed policies are fully user-controlled and allow for more granular permissions control.
AWS managed policies provide which of the following benefits? (Select all that apply)
- A) Automatic updates by AWS
- B) Customizable permissions
- C) Ability to be versioned
- D) One-click policy assignment
Answer: A, D
AWS updates managed policies as necessary, and they provide one-click policy assignment, which adds the necessary permissions for a specific job function to a user, group, or role. They are not customizable or versioned; those features are specific to customer managed policies.
Which policy type supports versioning for change management and rollback purposes?
- A) AWS managed policies
- B) Customer managed policies
- C) Both A and B
- D) Neither A nor B
Answer: B
Customer managed policies support versioning, which allows you to keep track of changes and roll back to previous versions if necessary. AWS managed policies do not support this feature.
True or False: You can attach a maximum of 10 customer managed policies to a single IAM role or user.
- Answer: False
You can attach up to 10 managed policies (whether AWS managed or customer managed) to a user, group, or role in IAM. There is no differentiation in this limit between AWS managed and customer managed policies.
Who is responsible for the maintenance and updating of customer managed policies?
- A) AWS
- B) The customer
- C) Both A and B
- D) Neither A nor B
Answer: B
The customer is responsible for creating, maintaining, and updating customer managed policies, giving them control over the permissions and allowing for custom policy creation.
True or False: Customer managed policies can be shared with other AWS accounts.
- Answer: True
Customer managed policies can be shared with other AWS accounts using AWS Resource Access Manager (RAM) or by referencing them in cross-account roles, providing flexibility and reusability of policies across accounts.
Which policy type is generally recommended when predefined permissions sets are sufficient for a user’s needs?
- A) AWS managed policies
- B) Customer managed policies
- C) Neither, as predefined permissions are never sufficient
- D) Both, as they can be equally effective
Answer: A
AWS managed policies are generally recommended when predefined permissions are sufficient for a userās needs, as they are easier to set up and are managed by AWS.
Can customer managed policies be tailored to enforce permissions based on specific tags?
- A) Yes
- B) No
Answer: A
Customer managed policies can include conditions that enforce permissions based on resource or user tags, offering fine-grained access control tailored to specific needs.
True or False: AWS managed policies are designed to be one-size-fits-all and cannot be edited.
- Answer: True
AWS managed policies are designed to cover a wide range of use cases and cannot be edited. To customize permissions, you should create a customer managed policy.
Which policy type is generally better suited for permissions that frequently change?
- A) AWS managed policies
- B) Customer managed policies
- C) Both A and B
- D) Neither A nor B
Answer: B
Customer managed policies are better suited for scenarios where permissions need to change frequently because they allow the customer full control over policy editing and versioning.
True or False: Both AWS managed policies and customer managed policies are stored as JSON documents.
- Answer: True
Both AWS managed policies and customer managed policies are represented and stored as JSON documents defining the permissions.
When you create a new IAM role in the AWS Management Console, which policy type is suggested by default for common use cases?
- A) AWS managed policies
- B) Customer managed policies
- C) Both A and B
- D) Neither A nor B
Answer: A
When creating a new IAM role in the AWS Management Console, AWS managed policies are suggested by default for common use cases to provide a quick and easy way to assign appropriate permissions.
Thanks for the post. It clarified a lot about AWS managed policies!
Could someone explain the security implications of using AWS managed policies over customer managed policies?
AWS managed policies are automatically updated by AWS, which can be a double-edged sword. They ensure that you have the latest security updates, but you lose a bit of control.
With customer managed policies, you have full control over the permissions, but it also means you need to stay on top of updates to avoid any security loopholes.
Great tutorial! Helped me a lot for the DEA-C01 exam preparations.
I think AWS managed policies are more suitable for beginners, while seasoned professionals might prefer creating custom policies for better control.
That’s a good point. AWS managed policies do simplify things for those who are new to AWS.
I’m not sure, but it feels like AWS managed policies might lack the flexibility needed for complex enterprise environments.
Absolutely. In large, complex environments, custom policies can offer the granularity necessary to meet specific requirements.
Thanks, this was really insightful!
What are the performance implications, if any, when using AWS managed policies vs. customer managed policies?
For anyone preparing for the DEA-C01 exam, it’s crucial to understand the benefits and drawbacks of AWS managed and customer managed policies.
Agree. It’s a key topic because managing permissions effectively is an essential skill for any AWS data engineer.