Use these steps if you are locked out of your Fedora CoreOS instance or need to change passwords or SSH keys. You must boot into single-user mode to regain access.
Access the instance console in the Vultr customer portal.
Click the Send CtrlAltDel button on the top right of the web console.
You can also click the Server Restart icon.
As the system boots, press E to edit the GRUB boot options. This happens quickly, you have approximately one second to intercept the boot process. If you miss the prompt, restart the server and try again.
Remove the console option that reads
single to the end of the kernel line.
Press CTRL+X to start.
The system will boot to rescue mode. Press ENTER for single-user (maintenance) mode.
As root, use the
passwd utility to change the core user password.
# passwd core Changing password for user core. New password: Retype new password: passwd: all authentication tokens updated successfully.
Reboot the system:
# /sbin/reboot -f
Add a new public key to
~/.ssh/authorized_keys.d/. Choose a logical filename for the key.
📝 Note: The web console does not support copy and paste. The easiest method is to upload the key to a public site, then use
curl. Delete the key from the website when finished.
$ curl https://example.com/id_rsa.pub >> ~/.ssh/authorized_keys.d/new_public_key
Set the permissions for the new public key.
$ chmod 600 ~/.ssh/authorized_keys.d/new_public_key
Recommended: Lock the core user password.
$ sudo passwd -l core passwd: success
Log out of the web console.