WSUS cleaning wizard fails 'Database Error'

If while running the WSUS cleaning wizard you get a Database error that looks like this:

You could reboot the server that WSUS is running on, but if it's used for other things also (e-mail, dhcp, dns, file, printing, etc...), you'll have to wait till there's downtime, before trying again.

Another option though is to restart the database service.
If you go to administrative tools -> services (or runbox services.msc), look for 'Windows Internal Database" and right click on it, and select restart

or from an admin command prompt:
sc stop mssql$microsoft##wid
sc start mssql$microsoft##wid

Then go back to the wsus management console, click on reset server node, and you should now be able to run the cleaning wizard (it'll probably take a couple hours or more, but it shouldn't give you an error),

And you were able to do this without interrupting whatever else may be running on it.

installing ssh fedora

Fedora nowadays doesn't have the ssh server by default, if you want it here's how (fedora no longer uses /etc/init.d):

yum install openssh
service sshd start
service sshd enable

note: if you want to start/enable other services on fedora you can replace sshd with the name of the other service.