Idea to recover access to serve is to change RSA key
We will try to login to server when it boot, and get access to single user mode.
After you setup the connection to console - restart server
at startup press F12 to get list of kernels available
YOu may see this screen
Then select Continue
on next screen select kernel and press e
- Next, select the Kernel version from the grub menu item and press e key to edit the first boot option. Now use the Down arrow key to find the kernel line (starts with “linuxefi“), then at the end of the line add the argument "rw init=/sysroot/bin/sh" as shown in the screen shot below
press Ctlr + x
after login execute
chroot /sysroot/
now /home folder is available and we can change ssh key
now you can edit this file
vi authrized_keys
get your new public key and past to this file then reboot
At end of the file add empty line #end
once you done reboot server
reboot -f
Change passwrod for root, or opc account
passwd root
passwd opc
If you have some issies with server - check also selinux, check /var/log/messages and see if something is not correct. Sometimes SELINUX may block your access causing you a problem. Disable it, recover access to server and then enable it again
