Mariadb fail to install in utubut 20.04 with previouly mysql installedpackage mariadb-common 1:10.3.25-0ubuntu0.20.04.1 failed to install/upgrade: installed mariadb-common package post-installation script subprocess returned error exit status 2

[Rodolfo]

I remove mysql 8 (apt remove mylsql-server) and try to install mariadb..
It fail to start...
I remove mariadb and manually delete the mysql directories... (/etc/mysql; /var/lib/mysql etc)
Now I can't install mariadb again...

ProblemType: Package
DistroRelease: Ubuntu 20.04
Package: mariadb-common 1:10.3.25-0ubuntu0.20.04.1
ProcVersionSignature: Ubuntu 5.4.0-54.60-generic 5.4.65
Uname: Linux 5.4.0-54-generic x86_64
ApportVersion: 2.20.11-0ubuntu27.12
Architecture: amd64
CasperMD5CheckResult: skip
Date: Thu Nov 19 11:44:01 2020
Dependencies: mysql-common 5.8+1.0.5ubuntu2
ErrorMessage: installed mariadb-common package post-installation script subprocess returned error exit status 2
InstallationDate: Installed on 2020-10-29 (21 days ago)
InstallationMedia: Ubuntu 20.04.1 LTS "Focal Fossa" - Release amd64 (20200731)
PackageArchitecture: all
Python3Details: /usr/bin/python3.8, Python 3.8.5, python3-minimal, 3.8.2-0ubuntu2
PythonDetails: N/A
RelatedPackageVersions:
 dpkg 1.19.7ubuntu3
 apt 2.0.2ubuntu0.1
SourcePackage: mariadb-10.3
Title: package mariadb-common 1:10.3.25-0ubuntu0.20.04.1 failed to install/upgrade: installed mariadb-common package post-installation script subprocess returned error exit status 2
UpgradeStatus: No upgrade log present (probably fresh install)
modified.conffile..etc.mysql.mariadb.cnf: [deleted]

[Faustin (fauust)]

Hi Rodolfo!
Thanks for your help in making Ubuntu better.

Be aware that removing /var/lib/mysql will remove all the data of your databases, so you should probably first create a backup of your databases.

For historical reasons, MariaDB and MySQL share the same PATH (/var/lib/mysql and /etc/mysql) so before installing mariadb over mysql, you should remove all the mysql related package and remove those directories.

More documentation can be found here:
https://mariadb.com/kb/en/migrating-to-mariadb-from-mysql/

Regards,
Faustin