Chapter 1. Image Service

Start the installation using virt-install as shown below:

[root@host]# qemu-img create -f qcow2 rhel7.qcow2 8G
[root@host]# virt-install --virt-type kvm --name rhel7 --ram 2048 \
--cdrom /tmp/rhel-server-7.2-x86_64-dvd.iso \
--disk rhel7.qcow2,format=qcow2 \
--network=bridge:virbr0 --graphics vnc,listen=0.0.0.0 \
--noautoconsole --os-type=linux --os-variant=rhel7

This launches an instance and starts the installation process.

[root@host]# virt-viewer rhel7

Set up the virtual machine as follows:

Update the /etc/sysconfig/network-scripts/ifcfg-eth0 file so it only contains the following values:

TYPE=Ethernet
DEVICE=eth0
ONBOOT=yes
BOOTPROTO=dhcp
NM_CONTROLLED=no

Update the system:

# yum -y update

Install the cloud-init packages:

# yum install -y cloud-utils-growpart cloud-init

Edit the /etc/cloud/cloud.cfg configuration file and under cloud_init_modules add:

- resolv-conf

The resolv-conf option automatically configures the resolv.conf when an instance boots for the first time. This file contains information related to the instance such as nameservers, domain and other options.

Add the following line to /etc/sysconfig/network to avoid problems accessing the EC2 metadata service:

NOZEROCONF=yes

To ensure the console messages appear in the Log tab on the dashboard and the nova console-log output, add the following boot option to the /etc/default/grub file:

GRUB_CMDLINE_LINUX_DEFAULT="console=tty0 console=ttyS0,115200n8"

Run the grub2-mkconfig command:

# grub2-mkconfig -o /boot/grub2/grub.cfg

The output is as follows:

Generating grub configuration file ...
Found linux image: /boot/vmlinuz-3.10.0-229.7.2.el7.x86_64
Found initrd image: /boot/initramfs-3.10.0-229.7.2.el7.x86_64.img
Found linux image: /boot/vmlinuz-3.10.0-121.el7.x86_64
Found initrd image: /boot/initramfs-3.10.0-121.el7.x86_64.img
Found linux image: /boot/vmlinuz-0-rescue-b82a3044fb384a3f9aeacf883474428b
Found initrd image: /boot/initramfs-0-rescue-b82a3044fb384a3f9aeacf883474428b.img
done

Un-register the virtual machine so that the resulting image does not contain the same subscription details for every instance cloned based on it:

# subscription-manager repos --disable=*
# subscription-manager unregister
# yum clean all

Power off the instance:

# poweroff

Reset and clean the image using the virt-sysprep command so it can be used to create instances without issues:

[root@host]# virt-sysprep -d rhel7

Reduce image size using the virt-sparsify command. This command converts any free space within the disk image back to free space within the host:

[root@host]# virt-sparsify --compress /tmp/rhel7.qcow2 rhel7-cloud.qcow2

This creates a new rhel7-cloud.qcow2 file in the location from where the command is run.

Start the installation using virt-install:

[root@host]# qemu-img create -f qcow2 rhel6.qcow2 4G
[root@host]# virt-install --connect=qemu:///system --network=bridge:virbr0 \
--name=rhel6 --os-type linux --os-variant rhel6 \
--disk path=rhel6.qcow2,format=qcow2,size=10,cache=none \
--ram 4096 --vcpus=2 --check-cpu --accelerate \
--hvm --cdrom=rhel-server-6.8-x86_64-dvd.iso

This launches an instance and starts the installation process.

[root@host]# virt-viewer rhel6

Set up the virtual machines as follows:

Update the /etc/sysconfig/network-scripts/ifcfg-eth0 file so it only contains the following values:

TYPE=Ethernet
DEVICE=eth0
ONBOOT=yes
BOOTPROTO=dhcp
NM_CONTROLLED=no

Update the system:

# yum -y update

Install the cloud-init packages:

# yum install -y cloud-utils-growpart cloud-init

Edit the /etc/cloud/cloud.cfg configuration file and under cloud_init_modules add:

- resolv-conf

The resolv-conf option automatically configures the resolv.conf configuration file when an instance boots for the first time. This file contains information related to the instance such as nameservers, domain, and other options.

To prevent network issues, create the /etc/udev/rules.d/75-persistent-net-generator.rules file as follows:

# echo "#" > /etc/udev/rules.d/75-persistent-net-generator.rules

This prevents /etc/udev/rules.d/70-persistent-net.rules file from being created. If /etc/udev/rules.d/70-persistent-net.rules is created, networking may not function properly when booting from snapshots (the network interface is created as "eth1" rather than "eth0" and IP address is not assigned).

Add the following line to /etc/sysconfig/network to avoid problems accessing the EC2 metadata service:

NOZEROCONF=yes

To ensure the console messages appear in the Log tab on the dashboard and the nova console-log output, add the following boot option to the /etc/grub.conf:

console=tty0 console=ttyS0,115200n8

Un-register the virtual machine so that the resulting image does not contain the same subscription details for every instance cloned based on it:

# subscription-manager repos --disable=*
# subscription-manager unregister
# yum clean all

Power off the instance:

# poweroff

Reset and clean the image using the virt-sysprep command so it can be used to create instances without issues:

[root@host]# virt-sysprep -d rhel6

Reduce image size using the virt-sparsify command. This command converts any free space within the disk image back to free space within the host:

[root@host]# virt-sparsify --compress rhel6.qcow2 rhel6-cloud.qcow2

This creates a new rhel6-cloud.qcow2 file in the location from where the command is run.

Start the installation using virt-install as shown below:

[root@host]# virt-install --name=name \
--disk size=size \
--cdrom=path \
--os-type=windows \
--network=bridge:virbr0 \
--graphics spice \
--ram=RAM

Replace the values of the virt-install parameters as follows:

To complete the setup, download and execute Cloudbase-Init on the Windows system. At the end of the installation of Cloudbase-Init, select the Run Sysprep and Shutdown check boxes. The Sysprep tool makes the guest unique by generating an OS ID, which is used by certain Microsoft services.