Creating subnets

Create a subnet for setting up VSP One SDS Block.

If you already created a subnet satisfying the following conditions, no more subnets need to be created because you can use the subnet for setting up VSP One SDS Block.

If you use an existing subnet, the number of characters must be from 1 to 76.
Only one IPv4 CIDR block should be allocated for each subnet for control network and internode network for storage node.
The CIDR block to be assigned to each subnet for compute node should be in accordance with the following conditions.
- If IPv4/IPv6 addresses (dual stack) are not used, only one IPv4 CIDR block should be allocated.
- When IPv4/IPv6 addresses (dual stack) are used, one IPv4 CIDR block and one IPv6 CIDR block should be allocated.
Each subnet for control network, internode network, and compute network must be set with the required IP address range.
- For the IP address range for the control network subnet, set a range of IPv4 addresses sufficient to create storage nodes (or tiebreaker nodes), controller nodes, and load balancers.
- For the IP address range for the internode network subnet, set a range of IPv4 addresses sufficient to create storage nodes.
- For the IP address range for the compute network subnet, set a range of IPv4 addresses sufficient to create storage nodes (or tiebreaker nodes) and a compute node.
  
  To use a combination of IPv4 and IPv6 addresses (dual stack), also set a range of IPv6 addresses sufficient to create storage nodes and a compute node.
Communication between the control network subnet and outside subnets must be allowed.
Communication between the internode network subnet and outside subnets must not be allowed.
To mitigate security risks, each subnet for control network, internode network, and compute network must be a private subnet.
When placing a compute node in a virtual network (or subnet) different from the compute network subnet, communication between the compute network subnet and the virtual network (or subnet) in which a compute node is to be placed must be allowed.
To perform remote copy (by using the Universal Replicator function) with a storage system placed in a network different from that for the subnet of VSP One SDS Block compute network, communication between the network for the compute network subnet and the network in which the storage system is installed must be allowed.
The control network must be able to use outbound connection to the internet or resource management private links.

Log in to the Azure portal.
Connect to any environment in which Azure CLI execution is available (Example: Cloud Shell).

The subsequent procedures use Cloud Shell.
To set the desired subscription, use the following command. If you do not want to set a subscription, go to the next step.
```
az account set --subscription <Subscription ID>
```
Place the template file in any directory in which you want to run the Azure CLI command, and then unzip it.
Two methods are available for obtaining the file: 1) through Azure Blob Storage, or 2) upload it from Manage files on Cloud Shell.

If you want to obtain the file from Azure Blob Storage, use the following Azure CLI command. (To obtain the file from Azure Blob Storage, you need to upload the file to a container beforehand.)
```
az storage blob download \
--account-name <account-name> \
--container-name <container-name> \
--name <Blob-name> \
--file <path-of-file-to-be output>
```
Among the extracted template files, edit SubnetConfigurationFile.parameters.json.
Parameter
- virtualNetworkName: Virtual network name to be used for setting up VSP One SDS Block
- controlSubnetName: Any control network subnet name (The valid number of characters is 1 to 76 for this value. Only alphanumerics, underscore, dot, and hyphen can be used. This value must start with an alphanumeric and end with an underscore or alphanumeric.)
- internodeSubnetName: Any internode network subnet name (The valid number of characters is 1 to 76 for this value. Only alphanumerics, underscore, dot, and hyphen can be used. This value must start with an alphanumeric and end with an underscore or alphanumeric.)
- computeSubnetName: Any compute network subnet name (The valid number of characters for this value is 1 to 76. Only alphanumerics, underscore, dot, and hyphen can be used. This value must start with an alphanumeric and end with an underscore or alphanumeric.)
- controlSubnetIPv4CidrBlock: CIDR block for IPv4 addresses of the control network subnet
- internodeSubnetIPv4CidrBlock: CIDR block for IPv4 addresses of the internode network subnet
- computeSubnetIPv4CidrBlock: CIDR block for IPv4 addresses of the compute network subnet
- computeSubnetIPv6CidrBlock: CIDR block for IPv6 addresses of the compute network subnet
- billingCode: Cost management tag
Note:
- When you specify the name of the control network subnet, internode network subnet, and compute network subnet, see the Microsoft Azure documentation to follow the Microsoft Azure naming convention.
- If you did not set IPv6 addresses for the virtual network, do not specify computeSubnetIPv6CidrBlock.
- The range of IPv4 addresses for controlSubnetIPv4CidrBlock, internodeSubnetIPv4CidrBlock, and computeSubnetIPv4CidrBlock should be in the form of CIDR block (Example: 10.160.226.0/24). The size of the subnet mask should be between /16 and /28.
  
  The range of IPv4 addresses for controlSubnetIPv4CidrBlock should be large enough to create storage nodes (or tiebreaker nodes), controller nodes, and load balancers. The range of IPv4 addresses for internodeSubnetIPv4CidrBlock should be large enough to create storage nodes (or tiebreaker nodes). The range of IPv4 addresses for computeSubnetIPv4CidrBlock should be large enough to create storage nodes and compute nodes.
  
  The range of IPv6 addresses for computeSubnetIPv6CidrBlock should be in the form of CIDR block (Example: 2406:da14:1f0f:f080::/64).
  
  The range of IPv6 addresses for computeSubnetIPv6CidrBlock should be large enough to create storage nodes and compute nodes.
  
  Note that IP addresses (reserved by Microsoft Azure) for the subnet created in this procedure cannot be used for VSP One SDS Block resources.

Run the following command.

az deployment group create \
--name mainTemplate \
--resource-group <any-virtual-network-resource-group-name> \
--template-file SubnetConfigurationFile.json \
--parameters SubnetConfigurationFile.parameters.json

Verify the execution results.

Verify that the CLI execution was successful. Alternatively, in the Azure portal, go to the Deployments window of virtual network resource group to verify that deployment was successful.