AZ-700 Question 4
Single answerYour organization has deployed a three-tier application in Azure within a single virtual network (VNet) using a 10.0.0.0/16 address space. Three subnets are defined for the front-end, mid-tier, and back-end, each sized at /24. Now you need to add several new subnets for additional services and anticipate needing more IP addresses than originally planned. You want to minimize disruption to the current environment. Which action represents the best approach for handling the upcoming expansions?
- A
Add new subnets as 10.0.3.0/24, 10.0.4.0/24, etc. until you exhaust the 10.0.0.0/16 space.
- B
Double the VNet CIDR to 10.0.0.0/15 by removing the existing CIDR and reassigning a larger one.
- C
Remove and recreate the entire VNet with a larger address space, then redeploy all resources.
- D
Add a second CIDR block (e.g., 10.1.0.0/16) to the existing VNet to expand available IP space.
Show answer and explanation
Correct answer: D
Explanation
Azure supports multiple address spaces in a single VNet, providing the flexibility to add new CIDR blocks as IP demands increase. This approach avoids significant reconfiguration or redeployment. For more details, see the official Microsoft documentation on virtual network address spaces: https://learn.microsoft.com/azure/virtual-network/virtual-networks-create-vnet-arm#add-additional-address-space-after-creation
- A. Incorrect.
Option 1: While adding successive /24 subnets within the existing 10.0.0.0/16 is straightforward, it might be insufficient if you further expand. Once the 10.0.0.0/16 range is filled, you must redesign or add another range, potentially disrupting existing services later.
- B. Incorrect.
Option 2: You cannot just 'double' a VNet CIDR by swapping from a /16 to /15 without removing the existing address space. Attempting to modify the current address space in place is not supported if subnets are already in use. This could cause service downtime.
- C. Incorrect.
Option 3: Removing and recreating the VNet would be highly disruptive. All dependent resources, such as virtual machines, would need to be redeployed. This is rarely a recommended approach in production environments.
- D. Correct.
Option 4: Adding a second CIDR to the existing VNet (for example, 10.1.0.0/16) is the best solution. Azure allows multiple address spaces per VNet, letting you continue using current subnets without disruption while also accommodating future growth.