Multi-account AWS CodeCommit access

Our developers access internally owned git CodeCommit repos across multiple AWS accounts. These AWS accounts are owned by us. It is important to qualify AWS/CodeCommit ownership here. Client owned CodeCommit access best practice is through IAM roles (out of scope for this post).

Scope of this post:

  1. organizational CodeCommit access spanning two AWS accounts
  2. concurrent access to repos in both AWS accounts

Solution options:

  1. Access CodeCommit in both accounts using git-remote-codecommit
  2. Access CodeCommit in 1st account using SSH & the 2nd using git-remote-codecommit.

A “no-no-option” worth noting: accessing CodeCommit in both AWS accounts using SSH.

Our reference implementation addresses both viable solution options.

  1. Generate AWS access key and secret access key for an IAM entity having AWSCodeCommitFullAccess
  2. Create AWS cli profile(s)
    aws --profile account1-gov configure
    Default region name [None]: us-gov-west-1
    Default output format [None]: json
  3. Install git-remote-codecommit
    pip3 install git-remote-codecommit
  4. Clone repos. Enjoy!
    git clone codecommit://account1-gov@repo-name repo-name-gc


Do not use GRC HTTP clone URL without profile (e.g., account1-gov) when concurrent access to account2 with SSH is in place.

AWS instance profile-based private Git repository access

Private Git repository access by CI/CD/CDE EC2s in secure subnets is an architectural best practice. However, using an IAM user to authenticate private Git repository access on EC2 is NOT a best practice. Why?

  1. Permanent key storage on EC2 is not secure.
  2. Revolving IAM user key pairs breaks git connectivity on EC2. Outcome: broken CI/CD!

IAM roles and instance profiles to the rescue!

Components of our reference implementation:

  1. A private subnet with external connectivity, i.e., NAT’d subnet. No IGW.
  2. An IAM role with AWSCodeCommitFullAccess
  3. AWS CodeCommit repository
  4. Jenkins Docker image with git-remote-codecommit setup

Launch steps:

  1. Create an EC2 instance in the private subnet with the instance profile.
  2. Run a Jenkins container on the EC2.
  3. Copy the HTTPS (GRC) URL from CodeCommit
  4. SSH to EC2 & Jenkins container and run the git clone on the HTTPS (GRC) URL to verify connectivity. Done!