Archive for March 6th, 2017

Exploring AWS Organizations

When AWS Organizations went GA, I was really happy. While I’ve had my personal AWS account for a while, I have a bunch of sites that aren’t personal in nature, and I wanted to spin them off into another account with the intention of having enough isolation that I could apply Terraform to those accounts freely.

The Good Parts

Inviting an existing account was painless

I performed this with the other account open in an incognito session. It was a simple matter to send the invitation from one account, and the offer showed up in under a minute in the Organizations tab in the other account.

The entire process took under 5 minutes.

Cross Account Access was set up automatically

I’ve spent a bunch of time setting up role switching. I really appreciate the automatic setup. (Though see Nit #2.)

Creating accounts is super simple

It’s 3 fields on the UI, only 2 are compulsory. The vast majority of information on the billing panel (Address, etc) is automatically copied from the root account.

SCPs are powerful

I blocked Route 53 as an experiment. After I applied the SCP, I can’t do anything in the R53 console:

Update: I had a nit about SCP policy inheritance being confusing – it was actually a misunderstanding about how policies are applied. I applied a restrictive policy to the root OU, expecting that it would result in default deny for accounts, but attaching a separate policy would override the restrictive policy. Unfortunately, the restrictive policy blocked me from being able to do anything, even on accounts with a FullAWSAcess policy attached.

This is a security feature – child nodes can’t be allowed to set a more permissive policy than what a (grand)parent specifies. So even if the child has the FullAWSAccess policy applied (like I had), it’s ineffective because my root said “Only have access to read-only billing details”, and the intersection of allowed permissions was “read-only access to billing data”.

As such, the root policy that should be something that either allows or denies something that you want applied to all accounts in your organization (except the master account). In practice I think people are going to end up leaving the FullAWSAccess policy on the Root OU, and apply more selective policies to nodes.

The Less Good Parts/Nits

The process wasn’t as pain free as hoped, here’s some rough edges I found, pretty much all issues I found on first use, and avoided once I knew about them:

1. The progress of account creation through the console isn’t clear.

Specifically, after clicking the “Create” button on the Add Account page, I get redirected back to the account list, and there’s a new row that just says “Creating…”.

There doesn’t appear to be an automatic refresh, so I manually refreshed. Now the “creating” message has disappeared, and a new account with an empty name and an account number appears in the account list.

Refresh a few more times, and the name eventually appears. I’m guessing the name field is only populated after the account is set up on the backend.

AWS: It’d be nice if the newly created account was somehow marked as “creation in progress”.

2. It is unclear how to get access to the newly created account.

AWS Orgs is probably aimed at a more experienced subset of AWS users, so I’d imagine they’d know how to do this. But it would be nice to explicitly mention that you have to role-switch to the named role that was created as part of the account. Something like “To access the new account, you need to switch role from your master account, using the account number and the name of the IAM role you provided when the account was created.”

You (also) don’t appear to be able to role switch to it as soon as the account number is listed in the account list. You have to wait until the account name shows up in the account list before you can role switch to the new account.

AWS: Also, the flow of having to go out of the Org page back to the AWS console to set up the switching seems easily optimized – a “Switch Role” button next to each account would be helpful.

3. What’s with all the emails?

I’m unsure if this will be fixed – right now it appears that Orgs is hooking onto the normal creation process. This means for every account you create you get “Welcome to Amazon Web Services” and “Your AWS Account is Ready – Get Started Now” emails sent to the new account’s email address.

4. The Auto-Created Role

First off – The role created by Organizations uses an inline AdministratorAccess policy, not the AWS managed one. Considering it has the same name (and actual Policy details) as the managed policy, I’m not sure why an inline policy was used. For what it’s worth, I tried swapping it out on my test account, and there were no adverse effects.

Secondly, what happens if I create an account, but don’t specify a role name? I’m guessing an account gets created without the cross account access setup, and I have to do the forgot-password dance on the email address I created the account with to get access. I’ve verified that you can do the forget password dance to set a password for the root account..

5. You can’t delete an account

I jumped in head first and created a (badly named) testing account before realizing this: Deleting accounts is (currently) not possible. The feature might be coming though! The “Remove Account” button is misleading – it will happily allow you to attempt to remove a created account, only for you to get an error.

The Organizations backend clearly knows which account is a created account (the status column shows “Created” vs “Joined”), so the “Remove Account” button could be disabled when a created account is selected. This is already done for the Master Account, so it might be simple to extend to created accounts. Or relabel the button “Remove Invited Account” to be super clear.

As a side note, I might be able to close a created account through the Billing panel (there’s a “Close Account” checkbox), but I’m not sure what would happen to my master account – and I’m kind of attached to it, so I’m not going to risk it.

Related, I can’t delete an account that failed to be created.

I managed to do this accidentally – see nit #1. I thought the initial creation had failed, and I tried to create the account again. The second request got accepted by Organizations, only to eventually error out because I reused the account email address.

6. A grab bag of other stuff

Three small things I encountered that didn’t really deserve their own section.

  • Orgs is keeping (caching?) their own copy of the Account Name. I renamed an account in the AWS Console, but the change didn’t replicate back to the Org account list. So there might be name drift if you rename accounts (there appears to be no way to rename an account through Organizations.)
  • It is unclear what happens if I update the details in the master account (eg the address). I’m guessing it’s not replicated to the other accounts.
  • The default VPC in my master account is 172.30.0.0/16. The default VPC in a created account is 172.31.0.0/16 – but for every created account. I’m not sure if this is accidental or intended, but the result is I can peer the default VPC in my root account with a default VPC in one of the created accounts. If it is intended, would it be possible to look at current VPCs and select a CIDR that isn’t in use?

7. SCPs are confusing

My original point here was the result of misunderstanding how the policies are applied. Only thing I’d suggest is add an “Effective Policy” listing under the SCP entry for each node.

SCP wasn’t enabled by default, despite my selecting Enable All Features in Settings. There’s a second step I missed: you have to enable SCPs on the root OU, not the master account – something which is documented, but I completely missed.

Tip: After navigating to the “Organize Accounts” tab, click “Home” to see the top level OU. The list of your acccounts and OUs is not the top level of your organization.

Also, having an SCP of FullAWSAccess appears to be required on the root OU. I removed it (after creating a stub policy, because at least one policy is required to be attached to the root), and promptly lost the ability to do anything in a cross-account role, even though those accounts still had the FullAWSAccess policy attached to each account individually:

To be clear, default allow is the sane default – the intention here is probably “You should be putting accounts in OUs and black/whitelisting on that”. But being unable to use role switching after the SCP on the root OU was weird.

I’m assuming there’s a combination of resources and permissions that I can add to an SCP that would allow the cross account stuff and nothing more. It’d be nice if AWS provided this as a reference.

That said

It could have gone far worse. The invite process was smooth for existing accounts, and Orgs is doing what is says it will, with some exceptions on the UI side of things.

I’m very sure they’ll iterate and improve it. I’m personally hoping there’s going to be a way to move resources between accounts. Being able to move S3 buckets to another account alone would be amazing.

,

No Comments