Unbuntu has installed Mysql 8 and nothing works

SYSTEM INFORMATION
OS type and version Ubuntu Linux 20.04.4
Webmin version 1.991
Virtualmin version 7.0-4
Related packages SUGGESTED

The last update of ubuntu has put Mysql 8
It wad before that a 5.7
Since, nothing works !
How can I do ?
Is there any support of Virtualmin, even if I must pay.
Can anyone help me ?

Hello,

Have you performed distro-upgrade by any chance, as Ubuntu 20.04 has MySQL 8 installed by default.

Start from restarting and then checking on MySQL status:

systemctl restart mysql
systemctl status mysql

20.04 always had MySQL 8: Ubuntu – Package Search Results -- mysql

If you have an upgrade, it was either because you were on 18.04 and dist-upgraded, or you had a third party package of the older version.

Going across major database versions usually requires a dump/restore. If you really did have 5.7 before, and you didn’t do a dump before upgrading, you’ll probably need to downgrade and then optionally dump, upgrade, and restore.

But, I would recommend you make sure that’s actually what the problem is, because unless you did something to make a major version change happen, it’s not what happened.

I have put 5.7 back and nothing works.
I shouldn’t trust upgrade proposed by webmin.
For a week, no more working websites, it’s awful, inimaginable.

You haven’t explained how you ever had MySQL 5.7, though? Ubuntu 20.04 has always had MySQL 8. You should not downgrade MySQL to a version that was never in use.

It was proposed by apt. Webmin is not a package manager, it only shows you what your package manager says is available.

If you’ll give us the information we need to be able to help you, we can help you get your sites back online. It’s probably a relatively easy fix. But, right now, I still have no idea what is going on with your system. You just seem interested in blaming someone.

there is trouble with innodb
some websites don’t appear anymore, no connection to the db.
others appeards, but the connection to the admin doesn’t work anymore.
this bug can be found on the web but no solutions here
And yes, I don’t understand how such a upgrade can be proposed if it causes the db on mysql not working anymore.
There are too many things to explains
I have spent hours trying to find a way to repair.
If you have a solution…

I’ve asked repeatedly how you ever had MySQL 5.7 on this system. Are you absolutely sure you had MySQL 5.7? Because Ubuntu 20.04 has MySQL 8. There is no reasonable scenario where you would have had 5.7 on an Ubuntu 20.04 system; unless you did a dist-upgrade from Ubuntu 18.04 (which is not something Webmin would do…it does not offer a dist-upgrade in the Software Packages module…since you say this was an update in Webmin, it cannot have been a dist-upgrade, so it cannot have gone from MySQL 5.7 to MySQL 8).

What is the exact error from the MySQL log? (And, by the way, downgrading to 5.7 was almost certainly a very bad idea, and I’ve said so several times in this thread, because I do not think you had 5.7 before the update.)