White Paper

Creating Windows Virtual Machine images for use with ESXi compute clusters in HP CloudSystem
• Firewalls are often disabled. OpenStack security groups provide a method for creating and applying firewalls as
each VM is instantiated by the end user. If default or minimum firewalls are already set in the image, network
troubleshooting can be difficult.
• Use a secure user login authentication mechanism that provides each end user with a unique password or key.
Configuring passwords into a common image is not a recommended solution. Instead, for Windows, end users
should set a password for an account in the launch dialog. For Linux, end users should choose a key pair for the
VM instance when the image is created.
• OpenStack supports the ‘cloud-init’ mechanism for passing data and scripts to a newly created VM instance. A
common practice is to perform final customization of the image when it first boots as a VM instance, using specific
information provided in the ‘create’ or ‘launch’ request.
• Make sure to log information to the console. When troubleshooting image issues during startup or issues related
to networking, it is extremely helpful to have the image log information to its console. You can access the console
through the CloudSystem Portal or through the virtualization layer using vSphere client, KVM command line
virsh commands, or Virtual Network Computing (VNC).
• Confirm the supported guest OS against the underlying hypervisor. VMware guest OS support is fairly broad; Red
Hat less so. To ensure a vendor supported configuration, make sure to conform to the vendor’s guest OS support
list.
• Make use of hypervisor tools and optimizations. CloudSystem provides a complete management environment for
images and provisioned VM instances. In addition, the virtualization layers (ESXi or KVM) have a critical role in
troubleshooting, development and performance optimization.
• Whenever possible, image size should be minimized. Image size impacts actions such as moving, using, and storing
images.
• You must account for any OS and software licensing for images instantiated as VMs. When a site license is available,
it can be configured in the image. Another approach is to connect images to license management frameworks
during configuration or after the VM instance is created.
Cloud-init tool for cloud images
Many of the issues described in the previous list have been solved for Linux and Windows images by the open source project
cloud-init. You can find information on cloud-init at https://cloudinit.readthedocs.org/en/latest/.
Originally developed for Amazon Web Service (AWS) and Amazon Elastic Compute Cloud (Amazon EC2) images, cloud-init is fully
functional in an OpenStack environment..
Where do images come from?
Images used in CloudSystem provisioning come from three major sources:
1. Images created in the hypervisor platform and then imported for use into CloudSystem.
2. Images downloaded from a public source and then imported for use into CloudSystem.
3. Snapshots of running VM instances in CloudSystem that are saved as images, and then used to provision new VM instances.
Option 1: Creating images from scratch
This approach is covered in detail in later sections of this paper. It gives you complete control over the contents, behavior and
features of the images used by your users.
2