Rollback and return of Ubuntu?

Question

ubuntu

iRedMail didn't want to install. It turns out that the hostname and dns-name of the mail server must be different, otherwise Postfix goes into error. I removed IRedMail and it affected MySQL. Now aptit can't install mysql-server. For stable operation, you need to roll back ubuntu. How to reset Ubuntu to its original state?

Answer 1

reinstall broken packages.
You can stupidly reinstall all the packages of the system.
for the future - set up backups

Answer 2

apt-get install -f
To start.

-f, --fix-broken
Fix; attempt to correct a system with broken dependencies in place. This option, when used with install/remove, can omit any packages to permit APT to deduce a likely solution. If packages are specified, these have to completely correct the problem. The option is sometimes necessary when running APT for the first time; APT itself does not allow broken package dependencies to exist on a system. It is possible that a system's dependency structure can be so corrupt as to require manual intervention (which usually means using dpkg --remove to eliminate some of the offending packages). Use of this option together with -m may produce an error in some situations. Configuration Item: APT::Get::Fix-Broken.