An IAM user is an entity that represents a person or application that interacts with AWS. It has specific credentials and permissions attached to it, like roles, to control access.
Configuring Assume Role Policy
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In Select type of trusted entity, configure the following:
Select AWS Account:Select Another AWS account.
Provide the Account ID of the Trusted/Management account.
Permissions: Configure the following permissions:
Attach Policy: Attach the policy that has permissions required for R53 sync (R53ReadWrite access).
Tags: This is optional. Provide some meaningful tags.
Role Name: Specify the same name as provided in step 3.dthe IAM role that you just created.
Click Create Role.