I am looking at migrating my GitHub repositories to GitLab self-managed instance with no internet access, having looked at the documentation regarding migrating repositories the Github rake task was an option but it requires internet access in order to communicate with GitHub and import the repository into GitLab therefore is of no use in my situation.
Is there a solution for importing GutHub repositories into a GitLab instance which has no internet access?
In short, no not really. You would have to do it manually.
Click the “Code” button and then download it as a zip file. Repeat this for all your repositories. Then create projects in your self-hosted Gitlab, and then clone these to your machine. Unpack the zip file into each of your projects and then push them to your gitlab instance.
Alternatively, why not temporarily give your self-hosted gitlab instance access to the internet. Click create new project in gitlab, and then click import project, choose the github option and then it will download everything from your github project, including issues, etc. Then repeat for each project. Then when finished, disable internet access for your self-hosted gitlab.
Thanks for the options, the first option of doing it manually will not include any previous commit history, issues, PRs etc. Am I correct?
Yes, this is why I suggest temporarily opening internet access to allow you to get all history by using the import method during project creation.