Fix the apt-get install error: “Media change: please insert the disc labeled ...” on your debian8 VPS

In order to avoid Debian to search for packages on a non-existent CDROM, which is most likely not present on a Linux VPS, you should change a simple parameter on the /etc/apt/sources.list file. You need to modify the aforementioned file if you get an output like this while using apt-get to install default packages:

Media change: please insert the disc labeled
 'Debian GNU/Linux 7.0.0 _Wheezy_ - Official amd64 CD Binary-1 20130504-14:44'
in the drive '/media/cdrom/' and press enter

Open and modify the file /etc/apt/sources.list

nano /etc/apt/sources.list

把这一行注释掉即可：

deb cdrom:[Debian GNU/Linux 8.2.0 _Jessie_ - Official amd64 CD Binary-1 20150906-11:13]/ jessie main