Backup creation fails since 17.1.0

[tDo]

After upgrading to the 17.1.x branch I noticed that the the automatic back creation would not create new backup-files anymore. Thus to check what's happening on the system, I tried to manually trigger the backup-task, which ran just fine until this last happened:

2024-07-02 08:14:40 +0200 -- Deleting tar staging files ... done
2024-07-02 08:14:40 +0200 -- Deleting backups/tmp ...
2024-07-02 08:14:40 +0200 -- Deleting backups/tmp ... done
2024-07-02 08:14:40 +0200 -- Deleting backup and restore PID file ... done
rake aborted!
Errno::ENOENT: No such file or directory @ rb_check_realpath_internal - /home/git/data/shared/external-diffs
/home/git/gitlab/lib/backup/targets/files.rb:178:in `realpath'
/home/git/gitlab/lib/backup/targets/files.rb:178:in `storage_realpath'
/home/git/gitlab/lib/backup/targets/files.rb:68:in `dump'
/home/git/gitlab/lib/backup/tasks/task.rb:25:in `backup!'
/home/git/gitlab/lib/backup/manager.rb:57:in `run_create_task'
/home/git/gitlab/lib/backup/manager.rb:145:in `block in run_all_create_tasks'
/home/git/gitlab/lib/backup/manager.rb:145:in `each_value'
/home/git/gitlab/lib/backup/manager.rb:145:in `run_all_create_tasks'
/home/git/gitlab/lib/backup/manager.rb:32:in `create'
/home/git/gitlab/lib/tasks/gitlab/backup.rake:12:in `block in create_backup'
/home/git/gitlab/lib/tasks/gitlab/backup.rake:75:in `lock_backup'
/home/git/gitlab/lib/tasks/gitlab/backup.rake:10:in `create_backup'
/home/git/gitlab/lib/tasks/gitlab/backup.rake:114:in `block (3 levels) in <top (required)>'
/home/git/gitlab/vendor/bundle/ruby/3.2.0/gems/rake-13.0.6/exe/rake:27:in `<top (required)>'
/usr/local/bin/bundle:25:in `load'
/usr/local/bin/bundle:25:in `<main>'
Tasks: TOP => gitlab:backup:create

It seems that it's missing the folder "/home/git/data/shared/external-diffs". I'll check if just creating the folder helps in the process.

Still do you know of any change that happened between 17.0.x and 17.1.x which resulted in this behavior difference?

[kkimurak]

This should be caused by upstream change https://gitlab.com/gitlab-org/gitlab/-/merge_requests/154914

I think we can take a similar approach to #2790 (fixed by #2901).

[tDo]

Also just verified that creating the folder manually with the git user as the owner also made the backup work again. So if anyone needs a quick workaround to create a backup for now.