2023年の今、PHP5.6の環境をDockerで構築することがあったので
Dockerfileを残しておく
FROM moodlehq/moodle-php-apache:5.6
WORKDIR /www
RUN apt-get -y update
RUN apt-get install -y init
RUN apt-get install -y libxml2-dev
RUN apt-get install -y libpng-dev
RUN apt-get -y install cronolog
RUN apt-get install -y default-mysql-client
RUN a2enmod rewrite
RUN a2ensite default-ssl
RUN a2enmod ssl
RUN apt -y install certbot
RUN docker-php-ext-install pdo pdo_mysql mbstring xml mysql
RUN docker-php-ext-install -j$(nproc) gd
RUN php -r "copy('https://getcomposer.org/installer', 'composer-setup.php');"
RUN php composer-setup.php
RUN php -r "unlink('composer-setup.php');"
RUN cp composer.phar /usr/bin/composer ; chmod 777 /usr/bin/composer
CMD /usr/sbin/apache2ctl -DFOREGROUND