In addition to custom images and Azure Marketplace images, Azure DevTest Labs enables a new way to create VMs: through formulas. A formula is a template in DevTest Labs that captures all the settings that you specify when you create a lab VM. It provides all the following benefits to make VM provisioning even more productive and flexible:
- Unlike a static VM image, changes in the environment can be captured on the fly through formulas, thanks to the lab artifacts. It basically means no more extra cost for you to generate or maintain new custom image files. For example, if you want a VM installed with the latest bits from your release pipeline, you can simply specify an artifact in the formula that deploys the latest bits (together with other settings such as a target base image). Whenever you use this formula to create VMs, you always get the latest bits deployed to the VM. You don't need to create new custom images every time when new bits are available from your pipeline.
- Formulas can define default/recommended settings that custom images cannot provide, including VM sizes and the virtual network.
- Because all the settings saved in a formula are shown as default values, the values can be updated when you use them to create a VM. This gives you more flexibility to feed different needs. For example, you can simply change the base image between different versions of Windows (or Linux) for compatibility testing, but keep all the other VM creation settings (artifacts, virtual networks, etc.) the same.
Using formulas to create VMs is as simple as creating VMs from a custom image or an Azure Marketplace image. All the formulas available in a lab are listed on top of the list in the Choose a base
blade when you create a lab VM. You don't have spend time specifying all the other properties (except the VM name and your credentials) to create the VM.
Figure 1: Create a lab VM by using a formula
Creating formulas is simple and straightforward. There are two ways to do so. You can create one from scratch in the lab by selecting Settings
Figure 2: Create formulas from lab settings
Or from an existing lab VM's blade, select Settings
> Create formula
to capture the settings to use for creating the VM:
Figure 3: Create formulas from an existing lab VM
Please try it today and let us know what you think about it! If you have an idea for how to make it work better, submit your feedback (or vote for others) at the Azure DevTest Labs feedback forum
. Have a question? Check out answers or ask a new question at the MSDN Community forum