How I connected a network_mode: host container to its database container

I have setup my FreePBX to use network_mode: 'host' but faced issues when it couldn’t connect to the MariaDB container which was not using network_mode: 'host'.

I fixed this by:

• Setting the MariaDB container to network_mode: 'host'
• Setting the FreePBX container to connect to 127.0.0.1 (DB_HOST=127.0.0.1). Setting it to localhost did NOT allow FreePBX to connect to MariaDB!