PHPMyadmin show host instead localhost when login - docker

Question

This is my first web stack using Docker with Nginx - PHP - MariaDB phpmyadmin for my side projects.
Everything work perfectly. But im confusing a bit about my phpmyadmin.
I noticed that when i login to phpmyadmin, why phpmyadmin pop-up a host-address behind my username?
Example: I have username call "test" - when i login to myadminphp , it show up error below
mysqli::real_connect(): (HY000/1045): Access denied for user 'test'#'192.168.0.4' (using password: YES)
When i create the user in mariadb terminal, it give me test#localhost, not test'#'192.168.0.4' .
By using
CREATE USER 'test'#'localhost';
Give my test#localhost user with full permission
GRANT ALL ON my_db.* TO 'test'#'localhost';
FLUSH PRIVILEGES;
And i can login as user by using mysql -u test -p
That im confusing here.
What is occured in my case? Can i switch from 'test'#'192.168.0.4' to test#localhost in PHPmyadmin?
Docker-compose.yml
version: '3.9'
services:
web:
image: nginx:latest
restart: 'always'
ports:
# Use port 80
- "80:80"
# Copy default config file to default folder
# By using volumes keywords
volumes:
- /home/hoangtho/Projects/:/usr/share/nginx/html/
- ./nginx.conf:/etc/nginx/conf.d/default.conf
php:
image: php:7.3-fpm-alpine
restart: "always"
build:
context: './php/'
volumes:
- /home/hoangtho/Projects/:/usr/share/nginx/html/
# PHP
mariadb:
image: mysql
restart: "always"
environment:
MYSQL_ROOT_PASSWORD: root
ports:
- "3306:3306"
# PHPMYADMIN
phpmyadmin:
image: phpmyadmin
restart: always
volumes:
- ./mysql:/var/lib/mysql
environment:
PMA_ARBITRARY: 1
PMA_HOST: mariadb
PMA_HOSTS: localhost,127.0.0.1
ports:
- "81:80"
Nginx.conf
server {
listen 80;
index index.php index.html;
server_name localhost;
error_log /var/log/nginx/error.log;
access_log /var/log/nginx/access.log;
root /usr/share/nginx/html;
autoindex on;
location ~ \.php$ {
try_files $uri =404;
fastcgi_split_path_info ^(.+\.php)(/.+)$;
fastcgi_pass php:9000;
fastcgi_index index.php;
include fastcgi_params;
fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name;
fastcgi_param PATH_INFO $fastcgi_path_info;
}
}
Dockerfile
FROM php:7.3-fpm-alpine
RUN docker-php-ext-install mysqli

Answer 1

The reason this happens is because MySQL returns the error message based on how you're connecting to the server. When you connect to 'localhost' it uses sockets and when you connect through any other host (including 127.0.0.1) it uses TCP/IP networking. MySQL/MariaDB users require a host field, which can be localhost, an IP address or hostname, or the wildcard operator %. The catch is that the wildcard operator does not include localhost connections.
Since you are connecting to a database that is not running on the same server as phpMyAdmin, your connection is not through localhost, so your user cannot have the host field of 'locahost'. Switching to test#localhost will not work because the connection is not local due to how Docker networking functions.
The other part of the problem here is that you're telling phpMyAdmin to connect to three servers, mariadb, localhost, and 127.0.0.1, which is odd and probably not needed. Based on what you've described, you should completely remove the array PMA_HOSTS from your docker-compose.yml and keep the PMA_HOST: mariadb.
So tweak your PMA_HOSTS and change your user to be #'%' or #'192.168.0.4', that should resolve these problems.