docker run vs. docker-compose up: same image, different outcome - docker

Question

TL;DR Using the same image, I get different results on running docker run and docker-compose up.
I am using the official php docker image and I want to install a set of extensions. Here is my Dockerfile:
FROM php:7.1.2-fpm
# Install software and dependencies (for extensions)
RUN apt-get update \
&& apt-get install -qy \
libcurl4-gnutls-dev \
libpng-dev \
libicu-dev \
mcrypt \
libmcrypt-dev \
libxml2-dev \
libfreetype6-dev \
libjpeg62-turbo-dev \
libpng12-dev \
git \
nodejs
# Install required PHP extensions
RUN docker-php-ext-configure gd --with-freetype-dir=/usr/include/ --with-jpeg-dir=/usr/include/ \
&& docker-php-ext-install -j$(nproc) gd \
&& docker-php-ext-enable gd
# Install and setup composer
RUN curl -sS https://getcomposer.org/installer | php \
&& mv composer.phar /usr/local/bin/composer
# Cleanup tasks
RUN apt-get clean
As you see I am trying to install the gd library. This is actually taken from their example. On running docker build I see that it runs the configure and install steps (Step 3/5):
Step 1/5 : FROM php:7.1.2-fpm
---> 7191c638ed10
Step 2/5 : RUN apt-get update && apt-get install -qy libcurl4-gnutls-dev libpng-dev libicu-dev mcrypt libmcrypt-dev libxml2-dev libfreetype6-dev libjpeg62-turbo-dev libpng12-dev git nodejs
---> Using cache
---> 1f53f9211603
Step 3/5 : RUN docker-php-ext-configure gd --with-freetype-dir=/usr/include/ --with-jpeg-dir=/usr/include/ && docker-php-ext-install -j$(nproc) gd && docker-php-ext-enable gd
---> Using cache
---> 4598a07d9fca
Step 4/5 : RUN curl -sS https://getcomposer.org/installer | php && mv composer.phar /usr/local/bin/composer
---> Running in 89c18c9ddf40
All settings correct for using Composer
Downloading...
Composer (version 1.4.0) successfully installed to: /var/www/html/composer.phar
Use it: php composer.phar
---> 059a1da3bb1a
Removing intermediate container 89c18c9ddf40
Step 5/5 : RUN apt-get clean
---> Running in 66c9cb68f684
---> f9543fa8b6e3
Removing intermediate container 66c9cb68f684
Successfully built f9543fa8b6e3
When I now do a plain docker run and ssh into the machine, the gd extension is available:
$ php -m
[PHP Modules]
Core
ctype
curl
date
dom
fileinfo
filter
ftp
gd
hash
iconv
json
libxml
mbstring
mysqlnd
openssl
pcre
PDO
pdo_sqlite
Phar
posix
readline
Reflection
session
SimpleXML
SPL
sqlite3
standard
tokenizer
xml
xmlreader
xmlwriter
zlib
[Zend Modules]
Now, here is the interesting part: When I build (docker build) the image and then run the container with docker-compose up, the extension is not installed.
I narrowed it down to docker-compose up being the problem, as I did a lot of diffent things:
docker-compose build {servicename} + docker run {image-ID} --> extension availabe
removed all running containers and images, removed all docker-compose images (docker-compose down)
tried it with remote registry, using dockerfile, even building the image and then entering the local image in the docker-compose.yml --> same result
UPDATE
My docker-compose.yml:
version: '2'
services:
php:
# this is the variant with the registry
image: registry.example.com/devops/php:base-php-fpm
volumes:
- './src:/code'
- './config/php:/usr/local/etc/php'
links:
- mysql
depends_on:
- mysql
nginx:
image: nginx:1.10
ports:
- "80:80"
volumes:
- './src:/code'
- './config/nginx:/etc/nginx'
depends_on:
- php
links:
- php
mysql:
image: mysql
ports:
- "3306:3306"

Answer 1

Turns out it is the volume mount of the config file into the config folder of php - can only be found in my compose file. It overwrites the auto-generated config of PHP.
One of these things that keep you busy the whole day without delivering the tiniest piece of functionality...
Thanks for your help, guys!