I installed CentOS 7 on virtualbox not long ago. A few bumps on the road, this post will help me jolt my memory in case I have to do it again.
1. Download CentOS-7-x86_64-DVD-1503-01.iso
2. Click “New” on Virtualbox Manager, enter your new virtual machine name “CentOS 7”
3. Select mem size, I picked 4G
4. Default “create a virtual hard drive now”
5. In the popup, default “VDI”, default “Dynamically allocated”, pick hard drive name, I picked a name without spaces, I picked 100G size.
6. Your VM “CentOS 7” is created, no OS installed yet.
7. Click on the new machine, then click Settings
8. I have an “empty” under Controller: IDE, click on it to have it selected
9. On the right hand side (under attributes), I see CD/DVD drive, there is a DVD icon, click on the icon, select “choose virtual CD/DVD disk file”
10. Navigate to your CentOS-7-x86_64-DVD-1503-01.iso
11. Start your VM, you may have multiple available ISOs to choose, select “CentOS-7-x86_64-DVD-1503-01.iso” to start your VM
12. Select Install CentOS 7
13. It will complain about input capture, you need to use “right control” key to navigate between host and VM
14. Importantly, select “Software selection”, then select “GNOME Desktop”. Here is why: when I didn’t select a desktop and tried to configure “Guest additions”, I wasted numerous hours trying to patch up the system to get it working, I just couldn't get it to work without the Desktop version. Then I re-installed the system and selected the “GNOME Desktop” version, I didn’t have to patch up anything, “Guest additions” worked flawlessly.
Two other important notes (I had relearn these tricks so many times after a while, hence the notes here):
1. if you get "Fast TSC calibration failed.", don't panic, don't just stare at the black error screen. For me, I just hit return key. That seems to do the trick for me. \
2. when you don't have network connection inside VM, run as (root), dhclient command!