Migrating repositories from Bitbucket Server to GitHub Enterprise Cloud

About repository migrations with GitHub Enterprise Importer

You can migrate individual repositories or all repositories from a BitBucket Server instance using GitHub CLI.

At this time, migrating from Bitbucket Server with the GitHub API is not supported.

Prerequisites

• To ensure you understand the known support limitations of the Importer, review "About GitHub Enterprise Importer."
• We strongly recommend that you perform a trial run of your migration and complete your production migration soon after. To learn more about trial run best practices, see "Preparing to run a migration with GitHub Enterprise Importer."
• While not required, we recommend halting work during your production migration. The Importer doesn't support delta migrations, so any changes that happen during the migration will not migrate. If you choose not to halt work during your production migration, you'll need to manually migrate these changes.
• For the destination organization on GitHub.com, you must be an organization owner or have the migrator role. For more information, see "Granting the migrator role for GitHub Enterprise Importer."
• You need the username and password for a Bitbucket Server account with admin or super admin permissions.

Step 1: Install the BBS2GH extension of the GitHub CLI

If this is your first migration, you'll need to install the BBS2GH extension of the GitHub CLI. For more information about GitHub CLI, see "About GitHub CLI."

1. Install the GitHub CLI. For installation instructions for GitHub CLI, see the GitHub CLI repository.

   Note: You need version 2.4.0 or newer of GitHub CLI. You can check the version you have installed with the gh --version command.

2. Install the BBS2GH extension.

   Shell

   gh extension install github/gh-bbs2gh
   

Any time you need help with the BBS2GH extension, you can use the --help flag with a command. For example, gh bbs2gh --help will list all the available commands, and gh bbs2gh migrate-repo --help will list all the options available for the migrate-repo command.

Step 2: Update the BBS2GH extension of the GitHub CLI

The BBS2GH extension of the GitHub CLI is updated weekly. To make sure you're using the latest version, update the extension.

gh extension upgrade github/gh-bbs2gh

Step 3: Set environment variables

Before you can use the BBS2GH extension to migrate to GitHub Enterprise Cloud, you must create a personal access token that can access the destination organization, then set the personal access token as an environment variable.

You'll also need to set environment variables for your Bitbucket Server username and password and, if your Bitbucket Server instance runs on Windows, your SMB password.

1. Create and record a personal access token that will authenticate for the destination organization on GitHub Enterprise Cloud, making sure that the token meets all requirements. For more information, see "Managing access for GitHub Enterprise Importer."

2. Set environment variables, replacing TOKEN with the personal access token you recorded above, USERNAME with the username of a Bitbucket Server account that has admin or super admin permissions, and PASSWORD with the password for the Bitbucket Server account.

   • If you're using Terminal, use the export command.

     Shell

     export GH_PAT="TOKEN"
     export BBS_USERNAME="USERNAME"
     export BBS_PASSWORD="PASSWORD"
     # If your Bitbucket Server instance runs on Windows
     export SMB_PASSWORD="PASSWORD"
     

   • If you're using PowerShell, use the $env command.

     Shell

     $env:GH_PAT="TOKEN"
     $env:BBS_USERNAME="USERNAME"
     $env:BBS_PASSWORD="PASSWORD"
     # If your Bitbucket Server instance runs on Windows
     $env:SMB_PASSWORD="PASSWORD"
     

Step 4: Set up blob storage

Because many Bitbucket Server instances sit behind firewalls, the GitHub CLI uses blob storage as an intermediate location to store your data that is reachable from the internet.

You will first generate an archive of the data you want to migrate and push the data to blob storage from behind your firewall.

The GitHub CLI supports the following blob storage providers:

• Amazon Web Services (AWS) S3
• Azure Blob Storage

Before you can run a migration, you need to set up a storage container with your chosen cloud provider to store your data.

Setting up an AWS S3 storage bucket

In AWS, set up a S3 bucket. For more information, see Creating a bucket in the AWS documentation.

You will also need an AWS access key and secret key with read-write access to your bucket.

When you're ready to run your migration, you will need to provide your AWS credentials to the GitHub CLI: region, access key, secret key, and session token (if required). You can pass them as arguments, or set environment variables called AWS_REGION, AWS_ACCESS_KEY_ID, AWS_SECRET_ACCESS_KEY, and AWS_SESSION_TOKEN.

You will also need to pass in the name of the S3 bucket using the --aws-bucket-name argument.

Setting up an Azure Blob Storage storage account

In Azure, create a storage account and make a note of your connection string. For more information, see Manage storage account access keys in Microsoft Docs.

When you're ready to run your migration, you can either pass your connection string into the GitHub CLI as an argument, or pass it in using an environment variable called AZURE_STORAGE_CONNECTION_STRING.

Step 5: Migrate a repository

You can migrate repositories with the gh bbs2gh migrate-repo command.

When you migrate a repository, by default, the BBS2GH extension of the GitHub CLI performs the following steps:

1. Connects to your Bitbucket Server instance and generates a migration archive per repository
2. Downloads the migration archive from the Bitbucket Server instance to the machine where you're running the BBS2GH extension of the GitHub CLI, using SFTP (Linux) or SMB (Windows)
3. Uploads the migration archives to the blob storage provider of your choice
4. Starts your migration in GitHub Enterprise Cloud, using the URLs of the archives stored with your blob storage provider
5. Deletes the migration archive

Alternatively, you can use the GitHub CLI to generate the archive, download that archive manually, and then use the GitHub CLI to continue the migration.

• "Allowing the GitHub CLI to download the migration archive"
• "Downloading the migration archive manually"

Allowing the GitHub CLI to download the migration archive

To migrate a single repository, use the gh bbs2gh migrate-repo command.

You must follow this step from a computer that can access:

• Your Bitbucket Server instance via HTTPS
• Your Bitbucket Server instance via SFTP, if your Bitbucket Server instance runs on Linux. In general, if you can access the server via SSH, then you can also use SFTP.
• Your Bitbucket Server instance via SMB, if your Bitbucket Server instance runs on Windows
• Your chosen blob storage provider

gh bbs2gh migrate-repo --bbs-server-url BBS-SERVER-URL \
  --bbs-project PROJECT --bbs-repo CURRENT-NAME \
  --github-org DESTINATION --github-repo NEW-NAME \
  # Use the following options if your Bitbucket Server instance runs on Linux
  --ssh-user SSH-USER --ssh-private-key PATH-TO-KEY
  # Use the following options if your Bitbucket Server instance runs on Windows
  --smb-user SMB-USER
  # Use the following option if you're using AWS S3 as your blob storage provider
  --aws-bucket-name AWS-BUCKET-NAME

Replace the placeholders in the command above with the following values.

Downloading the migration archive manually

By default, the BBS2GH extension of the GitHub CLI performs the entire migration, including downloading the migration archive from the Bitbucket Server instance using SFTP or SMB.

However, some customers prefer to download the migration archive manually, because their server does not offer SFTP access, for example. In that case, you can use the GitHub CLI to generate the archive, download that archive manually, and then use the GitHub CLI to continue the migration.

You must follow this step from a computer that can access:

• Your Bitbucket Server instance via HTTPS
• Your chosen blob storage provider

First, use the gh bbs2gh migrate-repo command with only the following arguments:

gh bbs2gh migrate-repo --bbs-server-url BBS-SERVER-URL \
  --bbs-project PROJECT \
  --bbs-repo CURRENT-NAME

Replace the placeholders in the command above with the following values.

Your migration archive will be generated, and its path will be printed in the command output:

[12:14] [INFO] Export completed. Your migration archive should be ready on your
instance at $BITBUCKET_SHARED_HOME/data/migration/export/Bitbucket_export_9.tar

In general, $BITBUCKET_SHARED_HOME will be set to /var/atlassian/application-data/bitbucket/shared on Linux and C:\Atlassian\ApplicationData\Bitbucket\Shared on Windows, but this may differ depending on your server configuration. To help you identify your shared home directory, see "Troubleshooting your migration with GitHub Enterprise Importer."

Download the migration archive from your Bitbucket Server instance, and store the archive on the machine where you're running the GitHub CLI.

To import your migration archive into GitHub, use the gh bbs2gh migrate-repo command again, with a different set of arguments:

gh bbs2gh migrate-repo --archive-path ARCHIVE-PATH \
  --github-org DESTINATION --github-repo NEW-NAME \
  # Use the following option if you're using AWS S3 as your blob storage provider
  --aws-bucket-name AWS-BUCKET-NAME

Replace the placeholders in the command above with the following values.

Step 6: Validate your migration and check the error log

When your migration is complete, we recommend reviewing your migration log. For more information, see "Accessing your migration logs for GitHub Enterprise Importer."

We recommend that you review your migrated repositories for a soundness check.

Step 7: Migrate multiple repositories

If you want to migrate multiple repositories to GitHub Enterprise Cloud at once, use the GitHub CLI to generate a migration script. The resulting script will contain a list of migration commands, one per repository.

Generating a migration script

You must follow this step from a computer that can access your Bitbucket Server instance via HTTPS.

To generate a migration script, run the gh bbs2gh generate-script command.

gh bbs2gh generate-script --bbs-server-url BBS-SERVER-URL \
  --github-org DESTINATION \
  --output FILENAME \
  # Use the following options if your Bitbucket Server instance runs on Linux
  --ssh-user SSH-USER --ssh-private-key PATH-TO-KEY
  # Use the following options if your Bitbucket Server instance runs on Windows
  --smb-user SMB-USER

If you want the script to download the migration log for each migrated repository, add the --download-migration-logs flag. For more information about migration logs, see "Accessing your migration logs for GitHub Enterprise Importer."

Replace the placeholders in the command above with the following values.

Reviewing the migration script

After you generate the script, review the file and, optionally, edit the script.

• If there are any repositories you don't want to migrate, delete or comment out the corresponding lines.
• By default, repository names in GitHub will follow a projectKey-repositoryName convention. For example, a Bitbucket Server repository named airports that is part of the open-source project, which has the key OS, would be called OS-airports in GitHub. If you want any repositories to have a different name on GitHub, update the value for the corresponding --github-repo flag.

Running your migration script

To migrate your repositories, run the generated script.

You must follow this step from a computer that can access:

• Your Bitbucket Server instance via HTTPS
• Your Bitbucket Server instance via SFTP, if your Bitbucket Server instance runs on Linux. In general, if you can access the server via SSH, then you can also use SFTP.
• Your Bitbucket Server instance via SMB, if your Bitbucket Server instance runs on Windows
• Your chosen blob storage provider

Before running the script, you must set additional environment variables to authenticate to your blob storage provider.

• For AWS S3, set the following environment variables.
  • AWS_ACCESS_KEY: The access key for your bucket
  • AWS_SECRET_KEY: The secret key for your bucket
  • AWS_REGION: The AWS region where your bucket is located
  • AWS_SESSION_TOKEN: The session token, if you're using AWS temporary credentials (see Using temporary credentials with AWS resources in the AWS documentation)
• For Azure Blob Storage, set AZURE_STORAGE_CONNECTION_STRING to the connection string for your Azure storage account.

Only connection strings using storage account access keys are supported. Connection strings which use shared access signatures (SAS) are not supported. For more information about storage account access keys, see Manage storage account access keys in the Azure documentation.

To migrate multiple repositories, run the script you generated above. Replace FILENAME in the commands below with the filename you provided when generating the script.

• If you're using Terminal, use ./.
  Shell

  ./FILENAME
  

• If you're using PowerShell, use .\.
  Shell

  .\FILENAME