Hi, everyone, and welcome to this lecture. In this lecture, we're going to cover instance templates. Instance templates are used to create VM instances and manage instance groups. When you create an instance template, what you're really doing is defining the machine type, the boot disk image, the container image, if necessary, any labels, and any other properties that will be used to deploy your instance or instance group.

Once the instance template settings are defined, you can use the template to create either a managed instance group or to create individual VM instances. The purpose of an instance template is to facilitate the creation of identically configured instances. That being the case, it's not possible to update or change an existing instance template once it's been created. If you need to make changes to a configuration, you need to create a new instance template.

It's important to note that instance templates are global resources; they are not bound to a specific zone nor to a specific region. However, when you create an instance template, you may need to specify some zonal resources. This, in essence, restricts the template to whatever zone in which those zonal resources reside. For example, if an instance template includes a persistent disk from the US-Central-1A zone, you won't be able to use that instance template in any other zone since the disk exists only in zone US-Central-1A.

Join me in the next lesson where I'll show you how to create and assign an instance template.