I created a Docker image for PHP 7.
The official PHP image lacks many commonly used extensions.
My image is extending it, having added most of extensions one uses in every day work, and a composer. It is usable to set up a PHP-FPM service quickly, without compiling extensions manually. Just init the configs in a mounted folders, edit configs, disable unused extensions, and you are done.
The image is here: https://hub.docker.com/r/grigori/phpextensions/
Further I will add docker compose config file to set PHP together with MySQL and Nginx.