I already have Google authenticator installed in my iPhone and I'm using it to signin to my AWS root account. I want to add the ability to login with MFA using my Android phone as well, using a corresponding token-generator Android app.
Is it possible to add a second device and how exactly? Or is AWS root account MFA bind to one (virtual) device?
You can only have one MFA device tied to your root account. You would need to setup a separate IAM user account for your separate device.
From the FAQ:
Q. Can I have multiple authentication devices active for my AWS account? Yes. Each IAM user can have its own authentication device. However, each identity (IAM user or root account) can be associated with only one authentication device.
Update: So while it's not officially supported, here is one guy who claims he was able to register Google Authenticator on two devices by doing both at the exact same time with the same QR code. Granted he's not doing this with AWS, but it could be worth a try.
http://www.joelclermont.com/2012/06/08/using-google-authenticator-on-more-than-one-device/
Update 2: I've started using Authy for MFA rather than Google Authenticator. One of the cool things Authy now supports is multi-devices for all your MFA tokens. I currently have my phone and my tablet setup with access to my AWS account using Authy Multi Device.
Here is the solution; When AWS MFA page shows the barcode, scan barcode from different devices (I've tried with 3) at the same time. They creates same code, filled form with same codes and it works.
I actually tried using the same secret configuration key from AWS on an iPhone, iPad and an Android using Google Authenticator and they all worked fine. The same with what @Jaap did.
In addition to the solutions above:
1) You cannot make a QR-code reappear after attaching an MFA device to AWS account. So if you need to add another virtual MFA device, delete the existing device, reattach it, and make a screenshot of the QR-code (or save Secret code) and then scan this QR-code with another device.
2) The QR-code is not expiring. I could use my code weeks after initialization.
来源：https://stackoverflow.com/questions/19723585/how-to-add-more-devices-to-aws-root-account-mfa