AWS SSO Tutorial with Google Workspace (Gsuite) as an IdP Step-by-Step

October 26, 2021

Name: Mike Elsmore
Twitter: @ukmadlz

AWS SSO and AWS Organization were released around 2017 and are probably the best way to manage AWS access at scale.

"AWS Single Sign-On (SSO) is a cloud SSO service that makes it easy to centrally manage SSO access to multiple AWS accounts and business applications. It enables users to sign in to an AWS IAM user with their existing corporate credentials and access all of their assigned accounts and applications from one place." Quote From AWS SSO page

This is a huge security and operational win, some highlights:

No need to rotate another new password in AWS IAM
2FA is already managed at your IdP (Google Workspace (G Suite)/Okta/AzureAD) level
When a user is leaving an organization he is automatically removed access from the organization
Easily automate the provisioning of AWS access when a user joins an organisation or department

In this article we, will go through a step-by-step guide to set-up AWS SSO with Google Workspace (previously G Suite) as an IdP. If you are using Google Workspace and use it as your central directory, this is the guide for you.

Prerequisite

You should have the AWS Organization (If you are not using it, This service combined with AWS SSO is a real game changer) set-up.

You need to sign up from the main account (also called "management account" ) and with enough permissions (usually Administrator permissions).

You will also need to make sure that you have access to the Google Workspace Admin and the relevant permissions to manage it.

Setting up AWS

Now that you have all the relevant permissions, everything is ready to configure for AWS SSO. Here is the step by step to set it all up:

From within the AWS Management Console search so single sign on and go to the AWS Single Sign-on.
Once on the service page, click the Enable AWS SSO button to start the service. This will take a few moments to complete.
Now that SSO is enabled, we need to change from the AWS directory to using an external provider. Select Choose your identity source.
Within the Settings page, select Change under the Identity source section.
Now we can change from the AWS SSO directory to an Active Directory (not what we need), or an External identity provider which is what we need to configure Google Workspace as the provider.
After you have selected External identity provider, scroll down to Service provider metadata and click Show individual metadata values.
You should now be presented with three fields that you can use to configure the next step on Google Workspace in the Google Admin console.
Don't close this screen, you will need it shortly after you have done the next section.

Google Workspace SAML setup

With the SSO URLs for our AWS organization, we can go to our Google Workspace Admin console and configure it.

When inside the Google Workspace Admin console, go to the Web and mobile apps settings. You can find this in the left-hand navigation menu under Apps.
Then select Add App from the top navigation, then Add custom SAML app.
Add an App name for the integration, I'm using AWS SSO to make it easier to find later.
We suggest you download the Google IdP metadata ready to put it back into AWS, this is under Option 1: Download IdP metadata.
Now to add the AWS SSO URLs from earlier to configure Google Workspace to point to the correct location. The mapping of data is:
- For ACS URL, enter the AWS SSO ACS URL.
- For Entity ID, enter the AWS SSO Issue URL.
- For Start URL, leave the field blank.
- For Name ID format, choose EMAIL.
- For Name ID, choose Basic Information > Primary email.
We don't need to apply anything to the Attribute mapping settings, so you can just click FINISH to move forward.
Once that's saved, it is time to enable it for everyone. In the User access section, open the settings by selecting the karat in the top right corner.
Now that you're in the Service status screen, select ON for everyone and SAVE. This will enable the service and allow you to manage who can have access to AWS, but to configure what they can access you need to do that in AWS SSO as Google Workspace is unaware of all the possible options.

Adding Google Workspace configuration to AWS SSO

Now that the AWS SSO service is enabled, and the Google Workspace SAML app exists, it's time to make them talk to each other.

Go back to the Change identity source screen in AWS SSO. Scroll to the bottom and add the GoogleIDPMetadata.xml file you downloaded a few moments ago, then click Next: Review.
To confirm this new identity source, you will need to type ACCEPT into the field under the warnings and then select Change identity source.
And now you are done with configuring the SSO and SAML connection between AWS SSO and Google Workspace. However, you aren't quite done as you need to configure the user provisioning at this point.

Setting up Users and Permissions

As of writing this, you can't automatically sync users between AWS and Google (this is being worked on over at OpenID) so we are limited to two options; manually creating the user (which we will go through) and using https://github.com/awslabs/ssosync to automate the process.

To manually add users, you will want to follow these instructions.

Go to Users in the sidebar of the AWS SSO service. Then select Add user.
Use the primary Google Workplace email address as the Username as well as the Email address, and fill the other fields accordingly. Then hit Next: Groups to save.
As part of this process, we aren't going to be adding groups so we can skip these phases by selecting Add user in the bottom right.
The user now needs to be associated with an AWS account. So select AWS accounts from the left navigation, select the checkbox next to the user, and click Assign users to attach them to the account.
On the next screen select the user again so that we can move on to permissions by clicking Next: Permissions sets.
As we haven’t configured and permission sets before we will have to do that now by clicking Create new permission set.
We will be using Use an existing job function policy, these are like AWS managed policies that you will be aware of if you have configured permissions inside AWS previously. Now Next: Details to select the policy.
From here you can select the policy you want to assign, I'll be using AdministratorAccess as this is for myself. But you could use PowerUserAccess as this would allow the user to build whatever they want, but not mess with other users and groups. Then click Next: Tags to apply this to the user.
Tags are optional, but they are advised for auditing and search at a later point. But I don't need them so we select Next: Review to move forward.
A quick once over to make sure everything is set correctly, then we can click Create to do so.
Back to our Assign Users screen, we can click the refresh icon to view our permission sets. From here we select the checkbox for the permissions set we want for the user, then select Finish to apply it.
It'll take a moment to provision, but you should get a Complete screen saying you are done.