How to install and configure CentOS using the “Minimal ISO” image

Hey there!

Recently I had to create a new VM with CentOS on it and thought that I could write these things down to help myself in the future. Hopefully, these notes will help you too 🙂

Create the Virtual Machine

First of all, let’s get an iso image withe CentOS, to start fresh I’ll be using the “Minimal ISO”, you can download it from https://www.centos.org/download/, just click on the “Minimal ISO” button.

While downloading create a new VM using your favorite software, I’ll be using VMware Workstation 14 Player.

Everything is quite self-explanatory so I’ll just paste the screenshots.

 

Install CentOS using the Minimal ISO image

When booting from the ISO downloaded before firstly check if it isn’t corrupted. This will only take a moment of your time.

When everything is ok you can continue installing the operating system on your VM.

Once again I’ll paste some screenshots from the process because once again it’s not really complicated.

Now just restart the VM. After rebooting you can log in to your machine using the root account or the other one which was created during the installation process. I’ve logged in as miko

Next thing I encourage you to do is to run the sudo yum update command. It will update all packages with available updates.

When executing this command with a non-root user miko we’ll get this error:

Add user to sudoers file

We can’t really do anything fun with this account, let’s switch to the root user and fix this problem by adding my non-root user miko to the sudoers file located in /etc/sudoers. The fastest way to doing so is by running these commands:

1. Switch to the root account

   su root
   

2. Open the sudoers file

   visudo
   

   OR

   vi /etc/sudoers
   

   Tips for using vi:

   • to edit a document press INSERT
   • to stop editing press Esc
   • to quit type :q and press Enter
   • to save and quit type :wq and press Enter

3. Find the line which contains the phrase ## Allow root to run any commands anywhere and add a new line underneath the one regarding the root user

   USERNAME    ALL=(ALL)       ALL
   

   In the end it should look something like this:

   ## Allow root to run any commands anywhere
   root    ALL=(ALL)       ALL
   miko    ALL=(ALL)       ALL
   

4. Save the file by pressing ESC, typing :wq and pressing Enter
5. To check if everything works like it should switch back to the non-root account

   su username
   

6. Once more try to update all of the installed packages

   sudo yum update
   

Setup network on CentOS Minimal install

It looks like we have the required privileges but can’t connect to the repository due to a network error. That’s because when installing CentOS from the Minimal ISO you have to manually turn on the network adapter and ideally make it to connect automatically every time we spin up the OS. To do so we have to:

1. List the Ethernet cards installed on your machine

   nmcli d
   

2. Start Network Manager

   nmtui
   

3. Choose Edit a connection
4. Choose your network interface and press Edit...
5. Check on the Automatically connect option, press OK and quit Network Manager
6. Reset network services (not always required)

   service network restart
   

7. Once again list ethernet cards installed on the machine

   nmcli d
   

Now when running the command sudo yum update you will get this:

 

Installing GUI on CentOS

The fastest way to install the GUI is to use the yum group option, let’s do it:

1. List all groups that are available to install

   yum group list
   

2. Install the GNOME Desktop environment

   sudo yum group install "GNOME Desktop"
   

3. Wait till it’s done installing…
4. Start GUI

   startx
   

5. To autostart the GUI run this command

   sudo ln -sf /lib/systemd/system/runlevel5.target /etc/systemd/system/default.target
   

6. Reboot the VM to check if everything works

   reboot
   

Looks great, doesn’t it?

I hope that this post was helpful. If you have any questions feel free to leave a comment below.