Creating an AWS CodeCommit repository for each project, using the main branch for production code, and creating a testing branch for code deployed to testing will meet the requirements. AWS CodeCommit is a managed revision control service that hosts Git repositories and works with all Git-based tools1. By using feature branches to develop new features and pull requests to merge code to testing and main branches, the developers can avoid code conflicts and lost work, and also implement code reviews and approvals. Option B is incorrect because creating another S3 bucket for each project for testing code and using an AWS Lambda function to promote code changes between testing and production buckets will not provide the benefits of revision control, such as tracking changes, branching, merging, and collaborating. Option C is incorrect because using the main branch for production and test code with different deployment pipelines for each environment will not allow the developers to test their code changes before deploying them to production. Option D is incorrect because enabling versioning and branching on each S3 bucket will not work with Git-based tools and will not provide the same level of revision control as AWS CodeCommit. References:

AWS CodeCommit

Certified DevOps Engineer - Professional (DOP-C02) Study Guide (page 182)

By default, the AWSCodeCommitPowerUser managed policy allows users to push changes to any branch in any repository in the AWS account. To restrict the developers ' ability to push changes to the main branch directly, an additional policy is needed that explicitly denies these actions for the main branch.

The Deny rule should be included in a policy statement that targets the specific repositories and includes a condition that references the main branch. The policy statement should look something like this:

{

" Effect " : " Deny " ,

" Action " : [

" codecommit:GitPush " ,

" codecommit:PutFile "

],

" Resource " : " arn:aws:codecommit: < region > : < account-id > : < repository-name > " ,

" Condition " : {

" StringEqualsIfExists " : {

" codecommit:References " : [

" refs/heads/main "

]

}

}

Verify No SCP Blocking Access:

Ensure that no Service Control Policy (SCP) is blocking access for developers to the S3 bucket. SCPs are applied at the organization or organizational unit (OU) level in AWS Organizations and can restrict what actions users and roles in the affected accounts can perform.

Verify No IAM Policy Permissions Boundaries Blocking Access:

IAM permissions boundaries can limit the maximum permissions that a user or role can have. Verify that these boundaries are not restricting access to the S3 bucket.

Make Necessary Changes to SCP and IAM Policy Permissions Boundaries:

Adjust the SCPs and IAM permissions boundaries if they are found to be the cause of the access issue. Make sure these changes are reflected in the code maintained in the AWS CodeCommit repository.

Invoke Deployment Through CloudFormation:

Commit the updated policies to the CodeCommit repository.

Use AWS CloudFormation to deploy the changes across the relevant accounts and resources to ensure that the updated permissions are applied consistently.

By ensuring no SCPs or IAM policy permissions boundaries are blocking access and making necessary changes if they are, the DevOps engineer can resolve the access issue for developers trying to access the S3 bucket.