Managing firewall rules across different platforms can be a complex and error-prone task. If you’re migrating from VMware NSX-T to Azure, you may need to replicate the firewall rules defined in NSX-T to Azure’s native Network Security Groups (NSGs). NSX-T and Azure NSGs use different rule formats, but with the right automation, you can simplify the process.
Let’s walk through how to automate the conversion of NSX-T firewall rules to Azure NSG rules using a Python script. This script reads the exported NSX-T rules, parses them, and generates the equivalent Azure CLI commands to create the necessary NSG rules in Azure.
Before diving into the script, make sure you have:
- An exported NSX-T firewall rule set in JSON format.
- Azure CLI installed and authenticated to your Azure environment.
Step 1: Export NSX-T Firewall Rules
You can export the firewall rules from NSX-T either through the NSX-T UI, CLI, or API. For simplicity, let’s assume you’ve already exported the rules in JSON format. The file might look something like this:
[
{
"name": "Allow-HTTP",
"direction": "in",
"action": "allow",
"protocol": "TCP",
"source": ["10.0.0.0/24"],
"destination": ["192.168.1.0/24"],
"destination_ports": ["80"]
},
{
"name": "Deny-All",
"direction": "out",
"action": "deny",
"protocol": "ANY",
"source": ["*"],
"destination": ["*"],
"destination_ports": ["*"]
}
]
Step 2: Python Script to Convert NSX-T Rules to Azure NSG
The following Python script will help automate the conversion of these NSX-T firewall rules into Azure CLI commands that can be used to create NSG rules in Azure.
import json
# Load NSX-T rules from a JSON file
def load_nsx_rules(file_path):
with open(file_path, 'r') as file:
return json.load(file)
# Convert NSX-T rules to Azure CLI commands
def convert_to_azure_nsg(nsx_rules, nsg_name, resource_group):
azure_commands = []
# Create the NSG
azure_commands.append(f"az network nsg create --resource-group {resource_group} --name {nsg_name}")
# Process each rule
for index, rule in enumerate(nsx_rules):
priority = 100 + index # Ensure unique priority for each rule
name = rule.get('name', f'rule-{index}')
direction = 'Inbound' if rule.get('direction', 'in').lower() == 'in' else 'Outbound'
action = 'Allow' if rule.get('action', '').lower() == 'allow' else 'Deny'
protocol = rule.get('protocol', 'Any').upper()
protocol = '*' if protocol == 'ANY' else protocol # Azure uses '*' for any protocol
source = ','.join(rule.get('source', ['*']))
destination = ','.join(rule.get('destination', ['*']))
destination_ports = ','.join(map(str, rule.get('destination_ports', ['*'])))
# Create the NSG rule
azure_command = (
f"az network nsg rule create "
f"--resource-group {resource_group} "
f"--nsg-name {nsg_name} "
f"--name {name} "
f"--priority {priority} "
f"--direction {direction} "
f"--access {action} "
f"--protocol {protocol} "
f"--source-address-prefixes {source} "
f"--destination-address-prefixes {destination} "
f"--destination-port-ranges {destination_ports}"
)
azure_commands.append(azure_command)
return azure_commands
# Save the Azure CLI commands to a file
def save_to_file(commands, output_file):
with open(output_file, 'w') as file:
file.write('\n'.join(commands))
# Example usage
if __name__ == "__main__":
# Path to the NSX-T exported JSON file
nsx_rules_file = 'nsx_rules.json'
# Azure NSG details
azure_nsg_name = 'MyAzureNSG'
azure_resource_group = 'MyResourceGroup'
# Output file for Azure CLI commands
output_file = 'azure_nsg_commands.sh'
# Load and convert the rules
nsx_rules = load_nsx_rules(nsx_rules_file)
azure_commands = convert_to_azure_nsg(nsx_rules, azure_nsg_name, azure_resource_group)
# Save the commands to a file
save_to_file(azure_commands, output_file)
print(f"Azure CLI commands saved to {output_file}")
How the Script Works:
- The script loads NSX-T firewall rules from a JSON file.
- It then converts these rules into Azure CLI commands. Each rule is processed to extract key parameters like the action, source, destination, protocol, and ports.
- The script generates commands to create a Network Security Group (NSG) and its rules in Azure.
- Finally, it saves the generated Azure CLI commands to a
.sh
file that can be executed to create the NSG rules in Azure.
Example Input and Output
Example Input (NSX-T JSON File)
[
{
"name": "Allow-HTTP",
"direction": "in",
"action": "allow",
"protocol": "TCP",
"source": ["10.0.0.0/24"],
"destination": ["192.168.1.0/24"],
"destination_ports": ["80"]
},
{
"name": "Deny-All",
"direction": "out",
"action": "deny",
"protocol": "ANY",
"source": ["*"],
"destination": ["*"],
"destination_ports": ["*"]
}
]
Example Output (Azure CLI Commands)
az network nsg create --resource-group MyResourceGroup --name MyAzureNSG
az network nsg rule create --resource-group MyResourceGroup --nsg-name MyAzureNSG --name Allow-HTTP --priority 100 --direction Inbound --access Allow --protocol Tcp --source-address-prefixes 10.0.0.0/24 --destination-address-prefixes 192.168.1.0/24 --destination-port-ranges 80
az network nsg rule create --resource-group MyResourceGroup --nsg-name MyAzureNSG --name Deny-All --priority 101 --direction Outbound --access Deny --protocol * --source-address-prefixes * --destination-address-prefixes * --destination-port-ranges *
Step 4: Executing the Commands
Once you have the .sh
file with the Azure CLI commands, simply execute the commands in your terminal to create the NSG and its rules in Azure:
bash azure_nsg_commands.sh
By automating the conversion of NSX-T firewall rules into Azure NSG rules, you can streamline your migration process and ensure consistency in your network security configurations. This Python script can be easily adapted to accommodate more complex rules or to generate ARM templates for even more advanced automation.