问题：

在chentos7中安装了selenium和chrome后启动程序报错：

raise exception_class(message, screen, stacktrace)
selenium.common.exceptions.WebDriverException: Message: unknown error: Chrome failed to start: exited abnormally
  (unknown error: DevToolsActivePort file doesn't exist)
  (The process started from chrome location /usr/bin/google-chrome is no longer running, so ChromeDriver is assuming that Chrome has crashed.)

原因：

1.chromedriver没有安装

2.chromedriver的版本和chrom浏览器的版本不对应

解决办法：

1.在 https://blog.csdn.net/huilan_same/article/details/51896672 网站中找到chrom浏览器和chromedriver对应的版本号

2.在 http://chromedriver.storage.googleapis.com/index.html 网站中下载chromedriver并放到对应的python环境（虚拟环境）下的.../site-packages目录下

完毕！