How to recover from running "chown -r ubuntu /"

Question

I ran chown -r ubuntu / on my system, and everything is gone. Is there any way to recover? This is a server server hosted on OHV.

Answer 1

There are (at least) two scenarios:

• You ran this as a regular user (not sudo) and you have locked yourself out of your account on the server (plus probably also caused some collateral damage).

• You ran this as root and have made the entire system unbootable.

In either case, the data is likely still there, but you'll need a way to access the system. Most cloud hosting providers have the ability to boot into a "recovery" or "rescue" mode, and OVH is no exception. See their rescue mode documentation here, and search their help for "rescue mode" for other documents.

I don't use OVH, so I'm going to run through the general recovery concept here based on my experience with other hosting providers. You'll probably need to do something like:

• Boot into rescue mode
• Examine the damage (system files or user files)
• Repair if possible (see this answer which @muru linked in the comments), which may return you to a bootable system.
• Regardless, it may be difficult to ensure that you've properly reset all files. Your best bet will still be to backup, reinstall, and recover.

If you cannot return the existing install to a bootable state ...

• Add storage to your server (this will likely be an additional charge)
• Create a new disk in that storage.
• Boot into rescue mode
• Copy over any critical data from the old disk to the new.
• Reinstall Ubuntu on the old disk.
• Copy the backed-up data back to the newly installed system.
• Delete the new drive
• Drop back to your normal storage tier.

Alternatively:

• Add storage to your server (this will likely be an additional charge) that is equivalent to what you already had.
• Create a new drive in that storage.
• Install Ubuntu on the new disk.
• Set the new disk to be the boot drive for the server.
• Boot into the new Ubuntu.
• Mount the old drive into something like /mnt/old
• Copy the critical data from the old drive to the new one.
• Delete the old drive
• Drop back to your normal storage tier.