Q. I created an Azure Virtual Network with a small address space and now need to expand it, is this possible?
A. Unfortunately you cannot modify the address space for a Virtual Network. While individual Virtual Subnets within a Virtual Network can be modified if no resources are within the Virtual Subnet, the address space of the Virtual Network itself cannot be modified post-creation. Therefore, when creating a Virtual Network in Azure always err on the side of being too large. There is really no downside to this approach. If you are in a position of needing to extend the address space of a Virtual Network there are two options:
- Create a new Virtual Network with a larger address space and migrate the VMs to the new Virtual Network
- Delete all VMs and gateways in the Virtual Network then resize the empty Virtual Network and add back the VMs and gateways
Note that both options are very invasive and not desirable.