Running a netinstall over HTTP to install CentOS

In this Tutorial we will learn how to initiate the process of running a netinstall over HTTP
(using the URL method) in order to install CentOS 6.

The CentOS network installation is a process by which a small image file is used to boot the computer and enable the download of all the necessary files that will be required to complete the installation of the full operating system.

Using this approach implies the advantage of not being required to download the DVD-based image files and for computers that do not have access to DVD drive; this can be of enormous benefit. Moreover, where you will only download the packages you need, unless you are intending to install more than one server then the entire netinstall-based approach (starting from downloading the initial installation image to finalizing the installation of your computer) not only provides greater flexibility, but it will also save time and offers the benefit of the full installer.

Minimum requirements

Before we begin, it is assumed that you have followed a previous recipe in which you downloaded the netinstall image of Centos 6, confirmed the checksum values of the image file, and that you have already created the relevant installation disk.

To complete this tutorial you will need an active Internet connection, and because this tutorial will serve as a starting point to the graphical installation process, you should be confident that your server can meet the following minimum requirements:

An Intel-based or AMD-based CPU (Pentium, AMD, Via, AMD64/EM64T)
At least 768 MB RAM (1GB or more recommended)
At least 10 GB hard disk space

How to do it

insert the netinstall disc, boot your computer from the optical drive, and wait for the welcome screen to appear:

1. On the welcome splash screen, use the Up and Down arrow keys to select and highlight install or upgrade and existing system. When you are ready, press the Return key to proceed.

2. Having unpacked the necessary files, you will be presented with the disc found screen and asked if you would like to test the integrity of your installation disc. Remember, file integrity in this context refers to the quality of the data on the disc only, so if you are confident that your installation media is error-free and wish to continue with the installation, simply use the Left and Right arrow keys to choose Skip and press the Return key to proceed.

3. Alternatively, if you would prefer to test the integrity of your optical media, choose OK and follow the onscreen instructions. A single test should take a few minutes depending on your hardware. When this process is complete, choose Continue to exit this phase and return to the main installation menu.

4. On the Language Selection screen, use the Up and Down arrow keys to select the preferred language. When ready, press the Return key to proceed.

5. On the Keyboard Selection screen, use the Up and Down arrow keys to select the preferred keyboard settings and press the Return key to proceed.

6. At this point you will now be asked to confirm the installation method. As we will be installing over HTTP (also referred to as the URL method), you should choose URL and press the Return key to proceed.

7. On the Configure TCP/IP screen, you will be asked to configure your network settings. By using the Up and Down arrow keys in conjunction with the Space bar, place a * in the preferred values. If your local area network supports dynamic IP assignment, then choose DHCP and when you are ready, highlight OK and press the Return key to proceed.

8. At this stage, your server will now attempt to configure the Ethernet devices before inviting you to complete the URL Setup screen. So depending on whether you have chosen a 32-bit or 64-bit installation, in the first dialog box use one of the following values:

For a 64-bit installation use

http://mirror.centos.org/centos/7/os/x86_64

For a 32-bit installation use

http://mirror.centos.org/centos/7/os/i386

Otherwise, you can obtain a list of local mirror sites from

http://www.centos.org/mirrors

Alternatively, you can also use a personal repository on your local network should you have access to such a facility.

Remember, if you need to enable an HTTP proxy, do this now by entering the relevant details. If you are in doubt, know that you do not use a Proxy or you are unaware of such a feature on your network then leave this section blank.

When you are ready, by using the Tab key, highlight OK and press the Return key to proceed.

9. On success, the installer will begin to retrieve the appropriate install.img file. This may take several minutes to complete, but once resolved a progress bar will then indicate all the download activity. When this process has finished, the installer will prepare the onscreen environment and present you with the installation welcome screen.