In today’s cloud-first world, it might seem strange, but air-gapped environments are more common than you’d think. These are systems that must stay physically isolated — no internet, no public dependencies. But how do DevOps teams manage to work with code that lives entirely online?
They use mirroring tools. Tools that can fetch open-source repositories and release archives, and store them locally. No need to pray your build won’t break after the next “npm install” or “git clone”.
TLDR:
If you’re prepping an air-gapped environment, you need to mirror public git repos and large release archives. Tools like GitLab, Artifactory, reposync, and GitHub Archive Program can help. Each serves a different purpose — from storing artifacts to full Git-based backup. Use a combo for the best results. No internet? No problem.
Why Mirror Repos and Binary Archives?
You mirror because you want control. No external dependencies. No version drift. No surprises before a critical deployment.
DevOps teams preparing air-gapped environments must download everything they’ll need in advance — source code, Docker images, Python wheels, RPM or DEB packages, Node modules, and more. And not just once. You’ll want continuous updates until the day of lockdown, and reproducible builds even after that.
Here are the top tools that teams rely on to get the job done right.
1. GitLab with Repository Mirroring
Best for: Keeping full backups of git repos and managing internal repos in air-gapped zones.
GitLab isn’t just a code-hosting platform — it’s also a powerful mirroring solution. GitLab Premium and higher allow automatic repository mirroring from any public Git repository. You can pull changes from a public repo into your private GitLab server on a schedule.
Why it’s awesome:
- You can mirror GitHub, Bitbucket, or any remote git repo.
- Preserves commit history and repo structure.
- Supports SSH keys and credentials so you can mirror even from private repos.
Once mirrored, everything lives inside your private GitLab in the air-gapped network. Developers can fork, clone, and push as if it’s any regular git server — because it is!
Pair this with GitLab CI/CD runners for fully offline builds and releases.
2. JFrog Artifactory
Best for: Storing and managing binary packages and release archives offline.
If code lives in Git, binaries live in Artifactory. Think of it as your warehouse for release tarballs, Docker images, Helm charts, Maven packages, Python wheels, and Node.js modules. Artifactory supports remote repositories that sync with public package registries like npm, PyPI, Docker Hub, etc.
Why it’s awesome:
- Can set up “remote repositories” that proxy public registries.
- Downloads are cached and kept locally forever (or as long as you want).
- Supports dozens of formats — you’re covered whether you’re using Conan or CocoaPods.
Once you’re ready to go fully offline, you just export your Artifactory data and bring it into your air-gapped environment. You now have your own private package universe.
3. reposync and dnf repos (for RPM-based systems)
Best for: Cloning entire Linux package repositories locally for Red Hat, CentOS, Fedora, and similar.
If you’re using an RPM-based Linux OS in your air-gapped setup, you’re going to need every possible package available from your desired repo — maybe thousands. The reposync tool makes this easy. It’s part of the yum-utils or dnf-utils package.
Why it’s awesome:
- Syncs the entire package list with metadata.
- Creates a usable local yum/dnf repository.
- Supports incremental syncing.
Running a local web server inside the air-gapped environment gives you access to fast, searchable, internal package repos. Say goodbye to pulling RPMs one by one.
If you’re working on a Debian-based system, don’t worry — there’s an equivalent called apt-mirror.
4. The GitHub Archive Program (and GH Archive Downloads)
Best for: Bulk downloading public GitHub activity and project data.
The GitHub Archive Program stores public repositories in cold storage (like the Arctic and other vaults), but it also opens doors for DevOps engineers needing mass downloads. While it’s more of a data preservation project, people use the GH Archive tools to dump vast amounts of repo data for local indexing or backups.
Why it’s awesome:
- You can get snapshots of entire directories of open-source projects.
- Snapshot-based mirroring ensures build consistency for years.
- Some tools (like github-dl or git clone –mirror + scripts) let you organize and automate download jobs.
This approach mixes a bit of scripting, some open data, and a ton of local storage — but for some security-sensitive teams, it’s worth it.
Bonus Tip: Combine and Automate!
DevOps folks rarely rely on one tool alone. Here’s how some teams glue them together:
- Use reposync weekly to update Red Hat packages.
- Use Artifactory to cache Docker, PyPI, and Maven releases.
- Mirror critical application repos with GitLab.
- Bundle everything together with rsync or rclone and move to your secured environment.
Then, throw in some automation magic — scheduled jobs, hooks, version tracking — and you’ve got a living, breathing, package and source-mirrored paradise.
Final Thoughts
Mirroring tools aren’t just about fixing bad Wi-Fi. They’re about control, repeatability, and resilience. Whether you’re securing military software, running a factory with no outside access, or preparing for compliance inspections, these tools make it possible to work entirely offline — and still keep up with the world.
Don’t rely on public resources at runtime. Download smart, store smart, and sleep soundly.
Recap: The Top 4 Tools
- GitLab – Great for Git repo mirroring and internal DevOps flows.
- Artifactory – Ideal for release archives, Docker images, and binary formats.
- reposync – Sync RPM package repos for secure Linux installs.
- GitHub Archive Program – For mass public repo backups and historical snapshots.
So build your offline DevOps toolkit. And go bravely where no Wi-Fi signal dares to reach.
