I have clients who want Docker on closed (air gapped) systems. Does anyone have any experience or advice to share?
What exactly do you mean by closed and air gapped? Is it some kind of “offline” environment without internet access?
Yes, that is a much better adjective, Ákos. The systems are in a secured environment and new software must come in via a CD/DVD that is scanned and analyzed before getting loaded onto the target system.
This is what I have actually done before so I am pretty sure you could create a mirror repository for Docker saved on a hard drive, attach it to one of the offline servers and set up an NginX server to make the repository available for each offline server machine.
If you have a debian based system, you can create the mirror using debmirror
On other systems you need to find an alternative to debmirror.
This way you could install everything offline not just Docker. Of course from time to time you would need to update the repositories.
Other solution could be downloading the installers like the deb packages in case of a debian based system but then you would have to deal with the dependencies.