On Mon 17 Feb 2020 at 15:27:06 (+0000), Graham Seaman wrote:
I hadn't thought of running a VM clone of the server - might be
generally useful. But the server's main jobs are as a router,
firewall, dnsmasq, mail server, which is where the main problems
usually are in upgrades, and I think it would be hard to duplicate the
low-level comms stuff meaningfully in a VM
Would it be possible to run a live stretch system (or install one)
on another machine, onto which you copy the files from your server.
You should be able to install a version of gitlab old enough to
handle your old data. (If necessary, for stretch, read jessie.)
You might not know which non-Debian files *are* necessary for gitlab
to run but presumably you know which trees of files you *don't* need
on this system: anything to do with the "main jobs" you mentioned,
for example.