How to connect locally hosted MySQL database with the docker container

If anybody is using mac os then please use docker.for.mac.host.internal instead of host.docker.internal as the environment variable.

Just use host.docker.internal instead of localhost.

To make it work on Linux, you just need to start your Docker container passing the parameter --add-host host.docker.internal:host-gateway

Find the host machine ip in the docker network. If you use docker-compose.yml version: "3" it's probably that that IP is: 172.18.0.1, but confirm it searching for the "Gateway" of your container (your host):

docker inspect <container-id-or-name> | grep Gateway
"Gateway": "",
            "IPv6Gateway": "",
            "Gateway": "172.18.0.1",
            "IPv6Gateway": "",

So inside your docker application point to MySQL as this: 172.18.0.1:3306 (maybe in a configuration file). Take into account that that IP is fixed as long as the docker network still the same (the network is created by docker-compose, and it is not removed unless you do docker-compose down)

Also, check that your MySQL is listening to all of its interfaces. In your my.cnf search for bind-address that should be 0.0.0.0 (consider security issues if your server has public IP).

---

As an alternative you can bring to the container the same networking as your host, in order to share the localhost, so the container will find mysql there. Use network mode as "host":

version: '3'
services:
  web-app:
    build:
      context: .
      dockerfile: web-app/Dockerfile
    ports:
       - 8080:8080
    network_mode: "host"

Then, point in your hibernate.properties to mysql as this: localhost:3306

Allow permission using mysqld.cnf

sudo nano /etc/mysql/mysql.conf.d/mysqld.cnf
bind-address            = 0.0.0.0

save your file and restart mysql server

sudo systemctl restart mysql.service

login to Mysql

mysql -h localhost -u root -p
GRANT ALL ON *.* TO 'root'@'localhost' IDENTIFIED BY 'yourpassword' WITH GRANT OPTION;
GRANT ALL ON *.* TO 'root'@'%' IDENTIFIED BY 'yourpassword' WITH GRANT OPTION;
FLUSH PRIVILEGES; 
EXIT;

Find your IP

ip addr show

And use it in your docker container 192.168.x.x