Docker php:php7.4-apache boot-loop after installing mysqli extension - php

Question

i am currently trying to run my Website in a Docker container using mysql and php with apache.
Docker-Compose:
version: '3.7'
services:
mysql:
image: mysql:latest
container_name: mysql
restart: always
environment:
//Database configuration variables
volumes:
- ./data/mysql/database:/var/lib/mysql
webserver:
image: php:7.4.12-apache
depends_on:
- mysql
restart: always
volumes:
- ./data/webserver:/var/www/html/
ports:
- 8888:80
command: bash -c "docker-php-ext-install mysqli && kill -HUP 1"
phpmyadmin:
depends_on:
- mysql
image: phpmyadmin:latest
container_name: phpmyadmin
links:
- mysql:db
restart: always
ports:
- 8889:80
volumes:
- /sessions
The problem began after i added the command-block to the webserver-container. Without it, the container runs perfectly and i can access the website. But with the command, the container gets stuck in a boot-loop and it seems that it tries to run the command over and over. At least thats what i guess after looking at the log of the webserver container.
However when i use docker exec -it *webserver* bash and run the installation command directly in the container, it works perfectly. I then restart apache with kill -HUP 1 and the Website works as intended. Does anyone know what the problem is here?

Answer 1

Have you tried doing the install and apache restart inside a Dockerfile instead?
Something like:
FROM php:7.4.12-apache
RUN apt-get clean && apt-get update && apt-get install -y php7.4-mysqli;
RUN service apache2 restart;
Then your docker-compose could be:
[...]
webserver:
build:
context: .
dockerfile: docker/webserver/Dockerfile
depends_on:
- mysql
restart: always
volumes:
- ./data/webserver:/var/www/html/
ports:
- 8888:80
[...]