Deploying a Barracuda CloudGen Firewall HA cluster in the Microsoft Azure Public Cloud requires a custom deployment and configuration to integrate the CloudGen Firewall with the Azure networking stack. Since the IP addresses are fixed and non-transferable between VMs, incoming traffic is handled and delivered via the Azure Load Balancer. This load balancer polls a service on the CloudGen Firewall's virtual server or a service that is reachable through the Forwarding Firewall service on the active firewall. When the virtual server fails over to the other unit, the load balancer will follow with a latency of a couple of seconds. For backend servers to be able to send traffic through the currently active unit, the CloudGen Firewall can directly manipulate the Azure routing table so that routing entries always point to the active unit of the HA cluster. Due to the limitation of Azure networking, all active sessions will time out whenever a failover occurs. Barracuda Firewall Control Centers in Azure do not support high availability configurations.
Deploy a High Availability Cluster
Create a high availability cluster by deploying two CloudGen Firewall VMs in the same subnet and availability zone. Incoming traffic is then forwarded to the active firewall by an Azure Load Balancer. User defined routing and the rewriting of the routes by the active firewall ensures that the backend VMs always use the active firewall as the gateway device.
For more information, see How to Configure a High Availability Cluster in Azure using PowerShell and ARM.
Azure Route Table Rewriting with Azure Cloud Integration
User Defined Routing is limited to one VM as the gateway device when creating a route. When you are using a high availability cluster as the gateway, the VM that is used changes when the virtual server fails over. Both firewalls are configured to access the Azure fabric and reconfigure the routing table when a failover occurs. For the firewall to rewrite the routes, you must configure Azure cloud integration.
For more information, see How to Configure Azure Cloud Integration using ARM.
Watch the following video to see an high availability firewall cluster using Traffic Intelligence for a hybrid cloud setup.