Even when we think of on-premises architecture, many of the key requirements were around high availability and scalability. Of course, this does not change when we architect in the public cloud, but these do become a lot easier and cheaper to do!
We have previously seen how we can deploy single GCE instances, but not many organizations will move to the public cloud to host only one VM. Business needs depend on the ability to react to demand and react to any instance failures.
Each of the VM instances deployed into the instance group comes from the same instance template, which defines the machine type, boot disk images, labels, and other instance properties that we spoke about previously in this chapter. Instance templates are global resources, which means they are not tied to a specific zone or region. Zonal resources in the template itself...