Example: Fedora image¶

Download a Fedora install ISO¶

1. Visit the Fedora download site.

2. Navigate to the Download Fedora Server page for a Fedora Server ISO image.

3. Choose the ISO image you want to download.

   For example, the Netinstall Image is a good choice because it is a smaller image that downloads missing packages from the Internet during installation.

Start the installation process¶

Start the installation process using either the virt-manager or the virt-install command as described previously. If you use the virt-install command, do not forget to connect your VNC client to the virtual machine.

Assume that:

• The name of your virtual machine image is fedora; you need this name when you use virsh commands to manipulate the state of the image.
• You saved the netinstall ISO image to the /tmp directory.

If you use the virt-install command, the commands should look something like this:

# qemu-img create -f qcow2 /tmp/fedora.qcow2 10G
# virt-install --virt-type kvm --name fedora --ram 1024 \
  --disk /tmp/fedora.qcow2,format=qcow2 \
  --network network=default \
  --graphics vnc,listen=0.0.0.0 --noautoconsole \
  --os-type=linux --os-variant=fedora23 \
  --location=/tmp/Fedora-Server-netinst-x86_64-25-1.3.iso

Step through the installation¶

After the installation program starts, choose your preferred language and click Continue to get to the installation summary. Accept the defaults.

# virsh dumpxml fedora
<domain type='kvm' id='30'>
  <name>fedora</name>
...
    <disk type='file' device='cdrom'>
      <driver name='qemu' type='raw'/>
      <source file='/tmp/Fedora-Server-netinst-x86_64-25-1.3.iso'/>
      <backingStore/>
      <target dev='hda' bus='ide'/>
      <readonly/>
      <alias name='ide0-0-0'/>
      <address type='drive' controller='0' bus='0' target='0' unit='0'/>
    </disk>
...
</domain>

# virsh attach-disk --type cdrom --mode readonly fedora "" hda
# virsh reboot fedora

Install the ACPI service¶

To enable the hypervisor to reboot or shutdown an instance, you must install and run the acpid service on the guest system.

Log in as root to the Fedora guest and run the following commands to install the ACPI service and configure it to start when the system boots:

# dnf install acpid
# systemctl enable acpid

Configure cloud-init to fetch metadata¶

An instance must interact with the metadata service to perform several tasks on start up. For example, the instance must get the ssh public key and run the user data script. To ensure that the instance performs these tasks, use the cloud-init package.

The cloud-init package automatically fetches the public key from the metadata server and places the key in an account. Install cloud-init inside the Fedora guest by running:

# yum install cloud-init

The account varies by distribution. On Fedora-based virtual machines, the account is called fedora.

You can change the name of the account used by cloud-init by editing the /etc/cloud/cloud.cfg file and adding a line with a different user. For example, to configure cloud-init to put the key in an account named admin, use the following syntax in the configuration file:

users:
  - name: admin
    (...)

Install cloud-utils-growpart to allow partitions to resize¶

In order for the root partition to properly resize, install the cloud-utils-growpart package, which contains the proper tools to allow the disk to resize using cloud-init.

# dnf install cloud-utils-growpart

Disable the zeroconf route¶

For the instance to access the metadata service, you must disable the default zeroconf route:

# echo "NOZEROCONF=yes" >> /etc/sysconfig/network

Configure console¶

For the nova console-log command to work properly on Fedora, you might need to do the following steps:

1. Edit the /etc/default/grub file and configure the GRUB_CMDLINE_LINUX option. Delete the rhgb quiet and add console=tty0 console=ttyS0,115200n8 to the option. For example:

   ...
   GRUB_CMDLINE_LINUX="rd.lvm.lv=fedora/root rd.lvm.lv=fedora/swap console=tty0 console=ttyS0,115200n8"
   

2. Run the following command to save the changes:

   # grub2-mkconfig -o /boot/grub2/grub.cfg
   Generating grub configuration file ...
   Found linux image: /boot/vmlinuz-4.10.10-200.fc25.x86_64
   Found initrd image: /boot/initramfs-4.10.10-200.fc25.x86_64.img
   Found linux image: /boot/vmlinuz-0-rescue-c613978614c7426ea3e550527f63710c
   Found initrd image: /boot/initramfs-0-rescue-c613978614c7426ea3e550527f63710c.img
   done
   

Shut down the instance¶

From inside the instance, run as root:

# poweroff

Clean up (remove MAC address details)¶

The operating system records the MAC address of the virtual Ethernet card in locations such as /etc/sysconfig/network-scripts/ifcfg-eth0 during the instance process. However, each time the image boots up, the virtual Ethernet card will have a different MAC address, so this information must be deleted from the configuration file.

There is a utility called virt-sysprep, that performs various cleanup tasks such as removing the MAC address references. It will clean up a virtual machine image in place:

# virt-sysprep -d fedora

Undefine the libvirt domain¶

Now that you can upload the image to the Image service, you no longer need to have this virtual machine image managed by libvirt. Use the virsh undefine vm-image command to inform libvirt:

# virsh undefine fedora

Image is complete¶

The underlying image file that you created with the qemu-img create command is ready to be uploaded. For example, you can upload the /tmp/fedora.qcow2 image to the Image service by using the openstack image create command. For more information, see the Create or update an image.