Creating Centos-7 Image for Openstack

Download the Centos-7 Minimal ISO from the centos ISO repo

http://isoredirect.centos.org/centos/7/isos/x86_64/

Setting up the KVM environment to create the custom images.

yum install kvm qemu-kvm python-virtinst libvirt libvirt-python virt-manager libguestfs-tools

Script for starting the KVM installation  cat createcentos7.sh
=============
IMAGE=Centos7.qcow2
VIRTIO_ISO=/root/virtio-win-0.1-81.iso
ISO=/ISO/CentOS-7.0-1406-x86_64-Minimal.iso

KVM=/usr/libexec/qemu-kvm
if [ ! -f "$KVM" ]; then
    KVM=/usr/bin/kvm
fi

qemu-img create -f qcow2 -o preallocation=metadata $IMAGE 8G

$KVM -m 2048 -smp 2 -cdrom $ISO -drive file=$VIRTIO_ISO,index=3,media=cdrom  -drive file=$IMAGE,if=virtio,boot=off -boot d -vga std -k en-us -vnc 192.168.2.10:4 -usbdevice tablet
=============
using any VNC client connect to 192.168.2.10:4  and do the rest of configuration.

Complete the installation do the following configurations after starting the image in openstack


cat <<EOF >/etc/sysconfig/network-scripts/ifcfg-eth0
DEVICE="eth0"
BOOTPROTO="dhcp"
ONBOOT="yes"
TYPE="Ethernet"
PERSISTENT_DHCLIENT=1
EOF

cat <<EOF > /etc/sysconfig/network
NETWORKING=yes
NOZEROCONF=yes
EOF
yum update -y

yum -y install https://dl.fedoraproject.org/pub/epel/7/x86_64/e/epel-release-7-2.noarch.rpm -y

yum install cloud-init

yum history new
yum clean all
truncate -c -s 0 /var/log/yum.log
rm -rf /var/lib/yum/*
rm -rf /var/lib/random-seed
rm -rf /root/install.log
rm -rf /root/install.log.syslog
rm -rf /root/anaconda-ks.cfg
rm -rf /var/log/anaconda*


Now save the Vm as a snapshot and use it again :)