Virtualization on the plant floor
Joel Conover, Paul Hodge, Grant Le Sueur, Anthony Baker, Jim Tessler
Building reusable engineering
Using templates with virtual machines can save reinventing your software wheel.
VMware vCenter templates provide opportunities for corporate engineering, system integrators, and other engineering teams to standardize work and simplify deployment of common system elements across multiple sites and customers. Templates provide a common starting point for the installation and configuration of automation software. Deploying a control system can take days of effort per workstation and/or server: it takes time to plan out system architecture, check for compatibility, install and patch the OS (operating system), and configure application content. Each of these steps also introduces risk if not done correctly.
With virtualization, the time and risk can be reduced drastically. Through the use of virtual machine (VM) templates, deployment can take minutes instead of days. Templates for workstations and servers are provided by some automation vendors with predefined software and OS builds or can be created by users for their specific systems.
Duplicate existing configurations
VMware vCenter Server allows system administrators to create templates from an existing VM. Your engineers can build a standardized VM for different defined workstations, such as operator or engineering workstations, that contain a defined build of OS and software content. This standardized VM is turned into a template and becomes a “golden image” for deployment for the rest of the system stations during implementation. It can also be reused in the future should the user decide to expand.
When expanding in the future, the user no longer has to worry about locating the exact installation media and hardware or worry about compatibility with the rest of the system. If the user requires an additional operator workstation, he or she can simply deploy a new VM from the template at any time.
Standardizing an image in such a manner can be extremely beneficial in validated industries. It reduces the amount of effort that needs to go into testing each station—not just on initial installation, but over the lifetime of the system when stations need to be maintained and replaced. Should the hardware (e.g., a thin client) fail at a station, it can be replaced without change to the image, reducing the need to revalidate the OS and software portion of that station.
Choosing the right applications
To determine when it makes sense to create a template, a user should keep a few things in mind. Not all software or services are appropriate for this type of deployment. Microsoft SQL Server and Windows components, such as the Active Directory, should not be installed on a template. Software packages that cannot tolerate changes, such as computer name and/or IP addresses, may cause conflicts if the user would like to replicate multiple instances in the same system.
VMware vCenter Server utilizes Sysprep for creating templates based on Windows OSs. Each version of Windows requires its own version of Sysprep that can be found on the install media provided or downloaded from the Microsoft website.
Each time an instance is deployed from a template with Sysprep loaded in vCenter Server, the user is able to customize the new VM. Upon initial boot, the user will be prompted to enter the information for computer name, network configuration (workgroup/domain), administrator credentials, and Windows licensing as required. Once this setup process is completed, the VM will reboot and bring the user to the desktop of the new instance, ready for use.
As concepts such as reusable engineering are increasingly promoted to improve engineering efficiency, VM Templates will prove to be an interesting opportunity for system deployment.
Anthony Baker is PlantPAx characterization and lab manager for Rockwell Automation.