用基于浏览器(webdriver)的selenium技术爬取数据，所以程序需运行在GUI环境下。本文分三个部分简要介绍安装GUI界面及远程连接的步骤。

安装GUI界面

大多数云服务器厂商提供的镜像都无GUI界面，所以要先安装图形环境。本文使用GNOME桌面环境：

yum -y groups install "GNOME Desktop"

这条命令将安装GNOME桌面的必要软件包，执行完后配置X系统使用GNOME:

echo "exec gnome-session" >> ~/.xinitrc

安装KDE或者MATE桌面环境的两个命令稍微不一样：

# kde
yum -y groups install "KDE Plasma Workspaces"
echo "exec startkde" >> ~/.xinitrc

# mate
yum --enablerepo=epel -y groups install "MATE Desktop"
​echo "exec /usr/bin/mate-session" >> ~/.xinitrc

以上便安装好了GUI桌面环境。

启动桌面环境有两种方式：

一次性的：在终端里输入startx； 系统启动时默认进入桌面环境： systemctl set-default graphical.target，然后重启；

安装vnc-server

有了桌面环境，一般可以通过云服务器厂商提供的web终端远程连接进入桌面。用web终端每次都需要打开浏览器，然后登陆云管理后台再连接，比较麻烦。我们采取直接从桌面客户端远程连接的方式，省去打开浏览器和登录云管理后台的操作。

远程桌面技术有多种，例如VNC, TeamViewer, RDP等，本文使用免费且广泛使用的VNC。

在服务器上先安装服务端(tigervnc是tightvnc的分支)：

yum install -y tigervnc-server

接着复制一份VNC配置：

cp /lib/systemd/system/vncserver@.service /etc/systemd/system/vncserver@:1.service

注意上述命令参数重的“@:1”，可以将数字1换成30000内的任意数字，“5900+数字”即为程序的显示（监听）端口，如”@:1″表示监听5901端口。

编辑该配置文件，将文件内的<USER>替换成远程连接时的登录用户名（如果是root，注意将第二个<USER>所在行的”/home”移除掉）。以root身份的配置示例：

# The vncserver service unit file
#
# Quick HowTo:
# 1. Copy this file to /etc/systemd/system/vncserver@.service
# 2. Replace <USER> with the actual user name and edit vncserver
#  parameters appropriately
#  (ExecStart=/usr/sbin/runuser -l <USER> -c "/usr/bin/vncserver %i"
#   PIDFile=/home/<USER>/.vnc/%H%i.pid)
# 3. Run `systemctl daemon-reload`
# 4. Run `systemctl enable vncserver@:<display>.service`
#
# DO NOT RUN THIS SERVICE if your local area network is
# untrusted! For a secure way of using VNC, you should
# limit connections to the local host and then tunnel from
# the machine you want to view VNC on (host A) to the machine
# whose VNC output you want to view (host B)
#
# [user@hostA ~]$ ssh -v -C -L 590N:localhost:590M hostB
#
# this will open a connection on port 590N of your hostA to hostB's port 590M
# (in fact, it ssh-connects to hostB and then connects to localhost (on hostB).
# See the ssh man page for details on port forwarding)
#
# You can then point a VNC client on hostA at vncdisplay N of localhost and with
# the help of ssh, you end up seeing what hostB makes available on port 590M
#
# Use "-nolisten tcp" to prevent X connections to your VNC server via TCP.
#
# Use "-localhost" to prevent remote VNC clients connecting except when
# doing so through a secure tunnel. See the "-via" option in the
# `man vncviewer' manual page.


[Unit]
Description=Remote desktop service (VNC)
After=syslog.target network.target

[Service]
Type=forking

# Clean any existing files in /tmp/.X11-unix environment
ExecStartPre=/bin/sh -c '/usr/bin/vncserver -kill %i > /dev/null 2>&1 || :'
ExecStart=/usr/sbin/runuser -l root -c "/usr/bin/vncserver %i"
PIDFile=/root/.vnc/%H%i.pid
ExecStop=/bin/sh -c '/usr/bin/vncserver -kill %i > /dev/null 2>&1 || :'

[Install]
WantedBy=multi-user.target