Docker with apache2 and PHP 5.6: mysqli & pdo extension installed, but not enabled

So Im trying to set up a docker server to use with some old applications that arent compatible with PHP 7

FROM php:5.6-apache

RUN apt-get -y update && apt-get upgrade -y

# Install tools && libraries
RUN apt-get -y install --fix-missing apt-utils nano wget dialog \
    build-essential git curl libcurl3 libcurl3-dev zip \
    libmcrypt-dev libsqlite3-dev libsqlite3-0 mysql-client \
    zlib1g-dev libicu-dev libfreetype6-dev libjpeg62-turbo-dev libpng-dev \
    && rm -rf /var/lib/apt/lists/*

# Composer
RUN curl -sS https://getcomposer.org/installer | php -- --install-dir=/usr/local/bin --filename=composer

# PHP5 Extensions
RUN docker-php-ext-install curl \
    && docker-php-ext-install tokenizer \
    && docker-php-ext-install json \
    && docker-php-ext-install mcrypt \
    && docker-php-ext-install pdo_mysql \
    && docker-php-ext-install pdo_sqlite \
    && docker-php-ext-install mysqli \
    && docker-php-ext-install zip \
    && docker-php-ext-install -j$(nproc) intl \
    && docker-php-ext-install mbstring \
    && docker-php-ext-configure gd --with-freetype-dir=/usr/include/ --with-jpeg-dir=/usr/include/ \
    && docker-php-ext-install -j$(nproc) gd \
    && pecl install xdebug-2.5.5 && docker-php-ext-enable xdebug \
    && echo "xdebug.remote_enable=1" >> /usr/local/etc/php/php.ini

# Enable apache modules
RUN a2enmod rewrite headers

EXPOSE 80

ENTRYPOINT ["/usr/sbin/apache2ctl", "-D", "FOREGROUND"]

All seems right, it builds without errors.

Except that both mysqli and PDO arent working, they are not enabled. I cant use them and I cant see then on php_info, they are really not being loaded

php_info says its loading these additional inis:

/usr/local/etc/php/conf.d/docker-php-ext-gd.ini, /usr/local/etc/php/conf.d/docker-php-ext-intl.ini, /usr/local/etc/php/conf.d/docker-php-ext-mcrypt.ini, /usr/local/etc/php/conf.d/docker-php-ext-mysqli.ini, /usr/local/etc/php/conf.d/docker-php-ext-pdo_mysql.ini, /usr/local/etc/php/conf.d/docker-php-ext-xdebug.ini, /usr/local/etc/php/conf.d/docker-php-ext-zip.ini

Checking pdo_mysql.ini & docker-php-ext-pdo_mysql.ini, the exnstions are being loaded correctly. Still, they arent there

Dont know what else to try. What am I doing wrong?

You can just issue a command to enable it so just before your EXPOSE 80 command you can do

RUN echo "extension=pdo_mysql" >> /usr/local/etc/php/php.ini \
 && service apache2 restart

This will right the enable extension code into the php.ini and restart apache2 so the new config gets loaded

Actually, I found the problem: there was a wrong php.ini in /var/www/html that was being loaded instead of the right one, this one was setting the exetension_dir wrongly and so no extensions were being loaded