CentOS 7 is an open source Linux distribution based on Red Hat Enterprise Linux (RHEL). It is a robust Linux distribution with active community. CentOS has been widely adopted as the major operating system for web servers and application servers of many small and medium enterprises. In this tutorial, we will learn how to install CentOS in just a few steps.

In our demonstration, we will use the Oracle VM virtual box for the OS installation. For those who may not know this, VirtualBox is a free, open source software, which act as a hypervisor and allows the users to create and run multiple OS (operating system) on their machine. First of all, we assumed that you have already installed the VirtualBox on your desktop PC or Mac.

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For the CentOS installation files, you may download from the official website:
https://www.centos.org/download/

Alternatively, you may also find the source ISO images in the following website mount point:
http://isoredirect.centos.org/centos/7/isos/x86_64/

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Part 1: Create the VM for the CentOS 7 installation

Step 1. On your local machine, launch the VirtualBox, then click the "New" button, and enter the details as below.

Name:	Enter the name of the virtual machine
Type:	Choose Linux
Version:	Select Red Hat (64bit)

Then Click the "Next" button


Step 2. On the next page, enter the desired memory size of your guest OS. Then click the "Next" button


Step 3. On next screen, choose "Create a virtual hard disk now" and click "Create"


Step 4. On the next screen, choose "VDI (Virtualbox disk image)" as the hard disk file type, and then click "Next"


Step 5. On the next screen, choose "Fixed size" and then click "Next"


Step 6. Enter the desired hard disk size (For example: 20 GB) and then click "Create"




It may take some time to create the virtual hard disk file. Just wait for it:


Then, you will see your guest OS has been created successfully in Virtual Box:


Step 7. Right click your Virtual machine (CentOS_7) and then select "Setting". You will then open the setting window of the guest OS.


Step 8. On the storage tab, select the "Empty" Controller IDE. Then in the optical drive icon, choose the virtual optical drive file just downloaded:

Part 2: Begin the CentOS 7 installation

Step 9. Now, on the Virtualbox Manager, just right click your newly created virtual machine and select "Normal Start". The guest OS interface will be prompted. In the interface, select: "Install CentOS 7"


Step 10. You will then see the CentOS 7 installation screen. Please choose your preferred language


Step 11. On the next screen, you will see the "Installation Summary" page. Now, select "Date & Time"


Step 12. You may configure your time and location in this page. Click "Done" when you completed.


Step 13. Next, Choose "Software Selection". Then select the required software for installation. Click "Done" when you completed.


Step 14. Next, select the "Installation Destination" option. In the "Installation Destination" window, choose "I will configure partitioning"


Step 15. Then you will enter the "Manual Paritiioning" window. In this window, you will start creating mount point on your disk.


Step 16. Now, click the "+" button to add the new mount point.


Please add the following mount point. (Or you may create the mount point and size based on your needs)

/boot	Non LVM	1 GB
/(root)	LVM	15 GB
Swap	LVM	2 GB

Step 17. Next, in "Network and Hostname", turn on the network card


Step 18. Configure the IP address and DNS


Step 19. Now click "Begin installation", then enter the root password


Step 20. Ensure you entered a strong password


Step 21. The installation is started. Just wait for it to complete


Step 22. After it is completed. Reboot it


Step 23. Congratulations! Your CentOS 7 linux OS is ready for use now. You may try the following command to verify the OS version. That's all.

Conclusion

This tutorial explains how to install CentOS 7 on Virtualbox step by step in details. By following this installation guide, you should be able to install CentOS succesfully. Let's try it out!