Docker: MySQL[2002] when trying to setup 2 DB containers - mysql

Question

Hi I'm trying to learn Docker.
As a starting point, I've followed DigitalOcean's setup tutorial for Laravel here.
I've managed to get all containers up and even finished building my Laravel app. Now I want to setup a 2nd DB for testing.
I duplicated the settings of the db part of docker-compose, and changed the container name and ports.
All containers setup fine, but whenever I try do run docker exec in either of the db containers, I get a 2002 error, which I did not encounter while I had only 1 DB container running:
ERROR 2002 (HY000): Can't connect to local MySQL server through socket '/var/run/mysqld/mysqld.sock' (2)
Dockerfile:
FROM php:7.2-fpm
# Copy composer.lock and composer.json
COPY composer.lock composer.json /var/www/
# Set working directory
WORKDIR /var/www
# Install dependencies
RUN apt-get update && apt-get install -y \
build-essential \
mysql-client \
libpng-dev \
libjpeg62-turbo-dev \
libfreetype6-dev \
locales \
zip \
jpegoptim optipng pngquant gifsicle \
vim \
unzip \
git \
curl
# Clear cache
RUN apt-get clean && rm -rf /var/lib/apt/lists/*
# Install extensions
RUN docker-php-ext-install pdo_mysql mbstring zip exif pcntl
RUN docker-php-ext-configure gd --with-gd --with-freetype-dir=/usr/include/ --with-jpeg-dir=/usr/include/ --with-png-dir=/usr/include/
RUN docker-php-ext-install gd
# Install composer
RUN curl -sS https://getcomposer.org/installer | php -- --install-dir=/usr/local/bin --filename=composer
# Add user for laravel application
RUN groupadd -g 1000 www
RUN useradd -u 1000 -ms /bin/bash -g www www
# Copy existing application directory contents
COPY . /var/www
# Copy existing application directory permissions
COPY --chown=www:www . /var/www
# Change current user to www
USER www
# Expose port 9000 and start php-fpm server
EXPOSE 9000
CMD ["php-fpm"]
docker-compose.yml:
version: '3'
services:
#PHP Service
app:
build:
context: .
dockerfile: Dockerfile
image: digitalocean.com/php
container_name: todo_app
restart: unless-stopped
tty: true
environment:
SERVICE_NAME: app
SERVICE_TAGS: dev
working_dir: /var/www
volumes:
- ./:/var/www
- ./php/local.ini:/usr/local/etc/php/conf.d/local.ini
networks:
- app-network
#Nginx Service
web:
image: nginx:alpine
container_name: todo_web
restart: unless-stopped
tty: true
ports:
- "80:80"
- "443:443"
volumes:
- ./:/var/www
- ./nginx/conf.d/:/etc/nginx/conf.d/
networks:
- app-network
#MySQL Service
db:
image: mysql:5.7.22
container_name: todo_db
restart: unless-stopped
tty: true
ports:
- "3306:3306"
environment:
MYSQL_DATABASE: todo
MYSQL_ROOT_PASSWORD: ent3r1n
SERVICE_TAGS: dev
SERVICE_NAME: mysql
volumes:
- dbdata:/var/lib/mysql/
- ./mysql/my.cnf:/etc/mysql/my.cnf
networks:
- app-network
db_test:
image: mysql:5.7.22
container_name: todo_db_test
restart: unless-stopped
tty: true
ports:
- "3307:3306"
environment:
MYSQL_DATABASE: todo
MYSQL_ROOT_PASSWORD: ent3r1n
SERVICE_TAGS: dev
SERVICE_NAME: mysql
volumes:
- dbdata:/var/lib/mysql/
- ./mysql/my.cnf:/etc/mysql/my.cnf
networks:
- app-network
#Docker Networks
networks:
app-network:
driver: bridge
#Volumes
volumes:
dbdata:
driver: local
Output of docker ps:
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
f5ccebc57f9d digitalocean.com/php "docker-php-entrypoi…" 15 seconds ago Up 13 seconds 9000/tcp todo_app
7cc53434d7d7 nginx:alpine "nginx -g 'daemon of…" 15 seconds ago Up 13 seconds 0.0.0.0:80->80/tcp, 0.0.0.0:443->443/tcp todo_web
7aab5318e7af mysql:5.7.22 "docker-entrypoint.s…" 15 seconds ago Up 13 seconds 0.0.0.0:3307->3306/tcp todo_db_test
5b72306f63a4 mysql:5.7.22 "docker-entrypoint.s…" 15 seconds ago Up 13 seconds 0.0.0.0:3306->3306/tcp todo_db

Answer 1

I have ever got the problem like this, because of image you use: image: mysql:5.7.22
You should use: image: mysql/mysql-server:5.7.
Hope it can help you.