This image is created for use with my lighttpd image. It is, however, a pretty straight forward generic php-fpm7 image. Use it as you please.
docker build -t php-fpm7 .
docker run \
--detach \
--name php-fpm7 \
-v /absolute/path/to/docroot/on/host:/var/www/localhost/htdocs:rw \
php-fpm7
The above creates a detached container named php-fpm7 and mounts a directory from the host's filesystem as a volume to the designated docroot inside the container.