まずdockerのipを確認しておく

$ docker-machine ip
192.168.99.101

php7つきの仮想imageを探す
$ docker search centos:php7
NAME DESCRIPTION STARS OFFICIAL AUTOMATED
padster83/centos7-php7-laravel5 centos7 php7 and larvel5.1 4 [OK]
skywidesoft/centos-apache-php7 1
bobbydvo/centos-php7 Docker container running Centos7 and the O… 0 [OK]
miyamotota/php7-centos67 PHP7 based CentOS6.7 0 [OK]

一番下の仮想imageが良さそうだったので、imageをpullする

$ docker pull miyamotota/php7-centos67

80port開放の状態で起動

$ docker run -it –publish 80:80 –name webphp7 miyamotota/php7-centos67:latest /bin/bash
apacheをinstallし起動させる
[root@8ff8c5a8cb27 /]# yum install httpd
[root@8ff8c5a8cb27 /]# /etc/rc.d/init.d/httpd start

dockerを再接続したい場合
$ docker start webphp7
$ docker attach webphp7

ローカルマシンからhttp://192.168.99.101へアクセスすると画面が開く

php -v
PHP 7.0.3 (cli) (built: Feb 3 2016 11:40:05) ( NTS )
Copyright (c) 1997-2016 The PHP Group
Zend Engine v3.0.0, Copyright (c) 1998-2016 Zend Technologies
with Zend OPcache v7.0.6-dev, Copyright (c) 1999-2016, by Zend Technologies
with Xdebug v2.4.0RC4, Copyright (c) 2002-2016, by Derick Rethans

php7の動作検証にdockerは使えそうです。