could not connect to MySQL server

[bluesailor]

Hi all,
I have installed joomla through the "Container Station" in QTS 4.4.1. Have SQL Server (MariaDB 5.5.57) enabled. In the initialisation of joomla I have Database type "MySQLi" (I think MariaDB ist synonymous to MySQLi ?). I can connect via phpMyAdmin with the user name/password as configured in the joomla initialisation page. Servername defined in joomla init page is "localhost". When connecting to PHPmyAdmin with the name/pw as in joomla init page i see in the section "Database Server":
Server: Localhost via UNIX socket
Server type: MariaDB
Server connection: SSL is not being used Documentation
Server version: 5.5.57-MariaDB - MariaDB Server
Protocol version: 10
User: joomla@localhost
Server charset: cp1252 West European (latin1)

When joomla is trying to connect to SQL Server in order to initialise the DB, the following error is returned: Could not connect to MySQL server.
When I change Database Type to MySQL (PDO) the following error is returned: Could not connect to PDO: SQLSTATE[HY000] [2002] Can't connect to local MySQL server through socket '/run/mysqld/mysqld.sock' (2 "No such file or directory")

Any suggestions? I do not want to install Postgres SQL as in my humble opinion MariaDB should be capable to accept MySQL connections as defined in joomla.
Thanks for your help.

[dolbyman]

did you install a container that has the sql server inside ?

[bluesailor]

Hi dolbyman
thanks for your help. When I expand "App Joomla" in the Container Station there is an entry for "joomla_web_1 (joomla-without-database 3.8.13) and an entry for joomla_db_1 (MariaDB 10.2). I think that should be joomla with the sql server interface.

[bluesailor]

In container station "App joomla" editing app environement the following is stated:db:
environment:
MYSQL_DATABASE: joomla
MYSQL_PASSWORD: joomla
MYSQL_ROOT_PASSWORD: admin
MYSQL_USER: joomla
image: mariadb:10.2
web:
environment:
DB_HOST: db
DB_NAME: joomla
DB_PASSWORD: joomla
DB_USER: joomla
image: edhongcy/joomla-without-database:3.8.13
links:
- db:db
ports:
- 10082:80