Ask HN: Ever worked with a service that can never be restarted?

The service has current up time of 55 Months. The general consensus therefore is that as long as it is never restarted it will continue to perform its function until a replacement can be put in place. Which seems a little fatalistic to me...

Has anyone experience of doing something sensible in a similar situation?

The problem is that anything you do that's potentially destructive in service of getting the system to be more sustainable is going to be met with heavy criticism. So you must be careful, the company has accepted the risk that they're in and you'll have to contend with that most likely.

First thing is first: is it a VM or a Physical machine? Things get a little easier if it's a VM because there might be vMotion or some kind of live-migration in place meaning hardware failure might not actually bring the service down.

Next thing is you absolutely have to plan for failure because the one thing that I learn as I learn more about computers is that they're basically working "by accident", so much error correction goes into systems that it absolutely boggles my mind and failures still get through. So, it's certainly not a question of "if" but "when" and plan for it being soon.

Now, the obvious technical things are:

* Dump the memory * Grab any files it has open from its file-descriptors (/proc//fd/) Your config file might be there... but somehow I doubt it. Attach a debugger and dump as much state as possible

Be sure to cleanly detatch : https://ftp.gnu.org/old-gnu/Manuals/gdb/html_node/gdb_22.htm...

Don't use breakpoints! They will obviously halt execution.

If it was my service I would also capture packet's and see what kind of traffic it receives most commonly; and I would make some kind of stub component to replace it before working on the machine. Just in case I break it and it causes everything to go down that depends on it.

But, this is a horrible situation, reverse engineering this thing is going to be a pain. Good Luck.

Surely there are options, have you tried de-compiling the source from the binary?

>but the physical config was accidentally overwritten and there are no backups

Any old dev PCs lying around somewhere? It's worth reaching out to the old developers to see if they have a copy, in really old legacy systems it's fairly likely someone will have a copy somewhere.