Migrate your repositories from GitLab to GitHub

Prerequisites

• You must have completed all previous phases of this guide.
• The GitLab project must be enabled for exports. See Enable project export and Sidekiq configuration for imports in the GitLab documentation.
• Ensure you understand the data that will be migrated and the known support limitations of the Importer. For more information, see Understand migrations from GitLab to GitHub.
• 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.

Performing a trial run

To help uncover problems that might be unique to your enterprise, we highly recommend performing a trial run of your migration. With a trial run, you'll learn:

• Whether the migration for a given repository can complete successfully.
• Whether you can get the migrated repository back to a workable state.
• How long a migration will take to run.

Trial runs can take place at any time, and work does not need to halt during the migration. To reduce the time it takes to complete your trial migrations, you can schedule the batches for your trial runs back-to-back. Users of those repositories can then validate the results on their own time.

1. Create a test organization for your trial migrations.

   You can use a single organization for all trial runs, or you can create one test organization for each intended destination organization. Consider including -sandbox at the end of the organization names, to clarify that the organizations are intended only for migration validation and not for production. You can delete the test organizations after you're done.

2. Run the trial migrations.

3. Confirm that you are able to complete the follow-up tasks in Follow-up tasks.

4. Ask users to validate the results of the migrations.

5. Resolve any issues uncovered by your trial migrations.

6. Optionally, delete the test organization.

Migrating a single repository

To migrate one repository, use the gh gl2gh migrate-repo command.

gh gl2gh migrate-repo \
  --gitlab-server-url GITLAB_SERVER_URL \
  --gitlab-group SOURCE_GROUP \
  --gitlab-project SOURCE_PROJECT \
  --github-org DESTINATION \
  --github-repo NEW_REPO_NAME \
  --use-github-storage

gh gl2gh migrate-repo \
  --gitlab-server-url GITLAB_SERVER_URL \
  --gitlab-group SOURCE_GROUP \
  --gitlab-project SOURCE_PROJECT \
  --github-org DESTINATION \
  --github-repo NEW_REPO_NAME \
  --use-github-storage

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

If you are not using GitHub-owned blob storage, see Configure blob storage.

Additional arguments

Generating a migration script

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 contains one migrate-repo command per repository.

To generate a migration script, run the gh gl2gh generate-script command.

gh gl2gh generate-script \
  --gitlab-server-url GITLAB_SERVER_URL \
  --github-org DESTINATION \
  --output FILENAME \
  --use-github-storage

gh gl2gh generate-script \
  --gitlab-server-url GITLAB_SERVER_URL \
  --github-org DESTINATION \
  --output FILENAME \
  --use-github-storage

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

By default, the script includes every project the token can access. To scope the script, add --gitlab-group GROUP, or --gitlab-group GROUP --gitlab-project PROJECT for a single project.

If you are not using GitHub-owned blob storage, see Configure blob storage.

Additional arguments

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.
• If you want any repositories to have a different name in the destination organization, update the value for the corresponding --github-repo flag.
• If you want to change the visibility of a new repository, add or update the corresponding --target-repo-visibility flag.

Migrate repositories

If your trial run was successful, and you were able to complete the follow-up tasks, you can proceed to the real migration.

Run the script you generated. 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