CentOS 6.10 Installation Guide: Step-by-Step

This guide explains how to install CentOS 6.10, the final release of the CentOS 6 series, on a physical machine or virtual machine. You will learn the exact steps from downloading the ISO to completing the post-installation setup, including disk partitioning, network configuration, and common troubleshooting.

Background: Why CentOS 6.10 Still Matters

CentOS 6.10 was released on June 30, 2018, as the last update to the CentOS 6 branch. It is based on Red Hat Enterprise Linux (RHEL) 6.10 and uses the 2.6.32-754 kernel. Although official support ended on November 30, 2020, many legacy systems still run it. Understanding how to install it is useful for maintaining older infrastructure, recovering old servers, or learning about pre-systemd Linux systems.

CentOS 6 uses SysV init, not systemd, and its installer is Anaconda, the same family as later versions but with an older interface. It supports both 32-bit (i386) and 64-bit (x86_64) architectures, though the 32-bit version is harder to find now. The default filesystem is ext4, and it uses GRUB as the bootloader.

Prerequisites and What You Need

Before starting, gather the following:

A CentOS 6.10 ISO image. The official mirrors no longer list it, but archived copies exist at the CentOS Vault. Look for CentOS-6.10-x86_64-bin-DVD1.iso (about 4.4 GB) or the smaller netinstall.iso.
A computer or virtual machine with at least 1 GB of RAM (2 GB recommended) and 10 GB of free disk space.
A blank DVD or a USB drive (at least 4 GB) to boot the installer.
If using a VM (VirtualBox, VMware, KVM), ensure virtualization extensions are enabled.

For physical hardware, note that CentOS 6.10 may not support very new chipsets or UEFI firmware well. If you have a modern PC, you may need to enable Legacy/CSM boot mode in BIOS.

Step-by-Step Installation Process

Here is the complete installation walkthrough:

Boot from the installation media. Insert the DVD or USB and restart. Press the key to enter the boot menu (often F12, F11, or Esc) and select your media. You will see a welcome screen with a boot: prompt. Press Enter to start the graphical installer, or type linux text for a text-based install.
Choose language and keyboard. Select your language (e.g., English) and keyboard layout (e.g., U.S. English).
Select installation method. The default is “Use CD/DVD” if you booted from the ISO. If you have the ISO on a hard drive or network, choose accordingly.
Hostname and network. Enter a hostname (e.g., server1.example.com). Click “Configure Network” to set a static IP if needed. By default, DHCP is used.
Time zone. Pick your timezone from the map or the list.
Root password. Set a strong root password. This is the administrator account.
Disk partitioning. Choose “Use All Space” for automatic partitioning, or “Create Custom Layout” for manual control. For a standard server, automatic is fine. If you want separate /home, /var, etc., create them manually.
Boot loader. The installer installs GRUB to the master boot record by default. Accept the default unless you have a specific reason not to.
Software selection. Choose a preset like “Minimal” for a bare system, “Basic Server”, or “Desktop” for a GUI. For a typical server, “Minimal” or “Basic Server” is recommended.
Begin installation. Review your settings and click “Next”. The installer will format the disk and copy files. This takes 10-30 minutes.
Reboot. When finished, click “Reboot”. Remove the installation media when prompted.

After reboot, you will see a login prompt (or graphical login if you installed a desktop). Log in as root with the password you set.

Post-Installation Configuration

Once booted, do the following to make the system usable:

Update the system. CentOS 6.10 is outdated, but you can still run yum update to get the last patches from the Vault. You must first edit /etc/yum.repos.d/CentOS-Base.repo to point to vault.centos.org instead of the old mirrorlist, since the original mirrors are gone.
Install basic tools. Use yum install -y vim wget net-tools to get essential utilities. Note that ifconfig is in net-tools, not installed by default.
Configure firewall. CentOS 6 uses iptables. To open a port, run iptables -I INPUT -p tcp --dport 22 -j ACCEPT and save with service iptables save.
Set up SSH. The SSH server is usually installed. Enable it with service sshd start and chkconfig sshd on.
Create a regular user. Use adduser username and passwd username for daily work instead of root.

Common Problems and Solutions

Several issues are common when installing CentOS 6.10:

“No valid device found” or disk not detected. This often happens on SATA controllers in AHCI mode. Enter BIOS and switch the SATA mode to IDE or Compatibility. Alternatively, at the boot prompt type linux nodmraid or linux noprobe.
Graphical installer fails to start. Try the text installer by typing linux text at the boot prompt. You can also add nomodeset to avoid graphics driver issues.
USB boot not working. Some USB sticks are not recognized. Use a different USB port (preferably USB 2.0) or use a DVD. Tools like Rufus can write the ISO in DD mode.
yum cannot find a mirror. As mentioned, edit the repo file to use baseurl=http://vault.centos.org/6.10/os/x86_64/ and remove the mirrorlist lines.
Network not coming up. Check if the interface is named eth0 (or em1). Run ifconfig -a to see it. Edit /etc/sysconfig/network-scripts/ifcfg-eth0 and set ONBOOT=yes.

Comparison: CentOS 6.10 vs CentOS 7 and 8

CentOS 6.10 differs significantly from later versions:

Init system: 6 uses SysV init with service and chkconfig; 7 and 8 use systemd with systemctl.
Filesystem: 6 defaults to ext4; 7 and 8 use XFS.
Network configuration: 6 uses ifcfg files and network service; 7+ uses NetworkManager and nmcli.
Firewall: 6 uses iptables directly; 7+ uses firewalld.
Package manager: Both use yum, but 8 uses dnf (which is yum-based).

If you are starting a new project, choose CentOS 7 or 8 (or a modern alternative like Rocky Linux or AlmaLinux). CentOS 6.10 is only for legacy compatibility.

Safety and Security Considerations

CentOS 6.10 is end-of-life and receives no security updates. Running it on an internet-facing machine is risky. If you must use it, follow these precautions:

Isolate it on a private network or behind a strict firewall.
Disable any unnecessary services and close unused ports.
Use strong passwords and consider SSH key authentication.
Do not store sensitive data on it if avoidable.
Migrate to a supported OS as soon as possible.

For offline or isolated environments, the lack of updates is less critical, but still plan for eventual migration.

Frequently Asked Questions

Can I install CentOS 6.10 on a modern PC with UEFI?
Yes, but it may be tricky. CentOS 6.10’s installer supports UEFI, but many modern systems have issues. You may need to disable Secure Boot and enable CSM (Legacy) mode. If you can, use a virtual machine instead.

How do I get the CentOS 6.10 ISO now that the official mirrors are gone?
Use the CentOS Vault repository at http://vault.centos.org/6.10/isos/x86_64/. This is the official archive for old releases. Download the DVD ISO or the netinstall ISO.

Is CentOS 6.10 still safe to use?
No, it is end-of-life since November 30, 2020. There are no security patches. Only use it in isolated test environments or for legacy applications that cannot run elsewhere.

What is the default root filesystem in CentOS 6.10?
The default is ext4, which is recommended. You can also choose ext3 or xfs during manual partitioning.

Can I upgrade from CentOS 6.10 to 7 or 8?
There is no supported in-place upgrade path from 6 to 7. You must do a fresh install. For 6 to 8, the gap is even larger; a fresh install is the only realistic option.

Why does my CentOS 6.10 installer not detect my SATA drive?
This is often due to the SATA controller mode. Go into BIOS and change the SATA mode from AHCI to IDE or Compatibility. Alternatively, boot with the linux nodmraid option.

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