Your VMs are running in a subnet that has a subnet mask of 255.255.255.240
The current subnet has no more free IP addresses and you require an additional 10 IP addresses for new VMs.
The existing and new VMs should all be able to reach each other without additional routes.
What should you do?
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A. B. C. D.C.
The current subnet mask of 255.255.255.240 allows for a total of 16 IP addresses, with 14 usable IPs after accounting for the network and broadcast addresses. Since all existing IPs are already in use, we need to expand the subnet to accommodate 10 additional IP addresses for new VMs.
Option A: Using gcloud to expand the IP range of the current subnet is a valid approach, but it requires that there is enough space in the IP range that the subnet is using. If there is enough space, you can update the IP range of the subnet by using the gcloud command gcloud compute networks subnets update SUBNET_NAME --range NEW_IP_RANGE where SUBNET_NAME is the name of the subnet, and NEW_IP_RANGE is the new IP range in CIDR notation. However, since there are no free IP addresses in the current subnet, this option is not viable.
Option B: Deleting the subnet and recreating it with a wider range of IP addresses is an option, but it is not the most efficient approach. Recreating the subnet will require downtime for the VMs and additional configuration steps to ensure that the VMs are properly connected to the network. Additionally, deleting the subnet will remove any network configurations, firewall rules, and routes associated with the subnet, which may cause disruptions or require additional configuration steps.
Option C: Creating a new project and using Shared VPC to share the current network with the new project is a viable option. Shared VPC allows for multiple projects to share a common virtual private cloud (VPC) network, which enables VMs in different projects to communicate with each other over a common network. By creating a new project and using Shared VPC, you can create a new subnet within the same IP range as the existing subnet, which will allow the new VMs to communicate with the existing VMs. This option does not require downtime or reconfiguration of the existing VMs, and it also allows for better management and organization of resources across projects.
Option D: Creating a new subnet with the same starting IP but a wider range to overwrite the current subnet is not a recommended approach. Overwriting the current subnet will cause all existing VMs to lose connectivity until they are reconfigured to use the new subnet. This approach also has the same downsides as option B, including downtime and additional configuration steps.
In conclusion, the best option for adding 10 additional IP addresses to the current subnet without downtime or reconfiguration of existing VMs is to create a new project and use Shared VPC to share the current network with the new project.