I am now running my Docker run just like the example provided AND can prove that I can connect to the MySQL db from within the container. There is nothing special here.
Can you show me an example of yours using Docker?
docker run -d \
-v /var/invoiceninja/public:/var/app/public \
-v /var/invoiceninja/storage:/var/app/storage \
-e APP_ENV='production' \
-e APP_DEBUG=0 \
-e APP_URL='http://ninja.dev' \
-e APP_KEY='base64:Qs7h2EtHleBdaLR+FsAKrBXtDAkzfzPKRfDDgTnxZSA=' \
-e APP_CIPHER='AES-256-CBC' \
-e DB_TYPE='mysql' \
-e DB_STRICT='false' \
-e DB_HOST='mysql-01.myhost.com' \
-e DB_DATABASE='ninja' \
-e DB_USERNAME='ninja' \
-e DB_PASSWORD='ninja123' \
-p '9321:9000' \
invoiceninja/invoiceninja
Connect to MySQL within the container:
ubuntu@ip-172-26-8-7:~$ sudo docker exec -it sharp_lewin /bin/sh
~ $ mysql -h mysql-01.myhost.com -u ninja -pninja123 ninja
Reading table information for completion of table and column names
You can turn off this feature to get a quicker startup with -A
Welcome to the MariaDB monitor. Commands end with ; or \g.
Your MySQL connection id is 3824725
Server version: 8.0.21 Source distribution
Copyright (c) 2000, 2018, Oracle, MariaDB Corporation Ab and others.
Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
MySQL [ninja]> show tables
-> ;
+-----------------+
| Tables_in_ninja |
+-----------------+
| NewTable |
+-----------------+
1 row in set (0.003 sec)
MySQL [ninja]>