Create VM in QEMU/KVM environment

Here I am going to create a VM. Since I’ve never tried CentOS 5, I decided to give it a shot. It has the old good sysv init system, it’s old, not obsolete. By this examle I will show you how to create and manage QEMU/KVM virtual machine without GUI utilities. First of all create a virtual disk of the desired size. Here for example, we will create a 20 GB disk with the raw disk format: You can also try to use qcow2 format which gives you some additional benefits.

qemu-img create -f raw -o size=10G /media/tb/qemu/centos5.img

Then start virt-install by running the following command:

virt-install \
  --name Centos5 \
  --ram 1024 \
  --disk path=/media/tb/qemu/centos5.img \
  --vcpus 1 \
  --os-type linux \
  --os-variant rhel5 \
  --network bridge=virbr0 \
  --graphics vnc,port=5999,listen=0.0.0.0 \
  --console pty,target_type=serial \
  --cdrom /media/tb/iso/CentOS-5.11-x86_64-netinstall.iso

Meaning of options are quite clear. By the way, you can check the list of OS variants with

virt-install --os-variant list

Check if the VM is up

virsh list --all

If you don’t see your VMs, try to add connection line

virsh -c qemu:///system list

or to make it permanent, uncomment the line in /etc/libvirt/libvirt.conf

uri_default = "qemu:///system"

Once the VM is running, you can connect to it via VNC and continue installation. I used VNC Viever for Mac OS. Pay attention, that VNC port was set to 5999.

Let the installation begin.

Configure CentOS 5 repo

Since CentOS 5 is not supported anymore, I replaced the preconfigured repo with:

# cat /etc/yum.repos.d/CentOS-Vault.repo
[C5.11-base]
name=CentOS-5.11 - Base
baseurl=http://vault.centos.org/5.11/os/$basearch/
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-5

[C5.11-updates]
name=CentOS-5.11 - Updates
baseurl=http://vault.centos.org/5.11/updates/$basearch/
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-5

[C5.11-extras]
name=CentOS-5.11 - Extras
baseurl=http://vault.centos.org/5.11/extras/$basearch/
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-5

[C5.11-centosplus]
name=CentOS-5.11 - Plus
baseurl=http://vault.centos.org/5.11/centosplus/$basearch/
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-5

As a result I got my CentOS 5 machine. To be honest, I removed it after a couple of hours playing around. It is mostly useles in modern world, but that was worth it.