In cloud service provider (CSP) environments, the standard and recommended method for achieving high availability (HA) across multiple availability zones (AZs) is to use a native cloud load balancer. The load balancer distributes traffic to multiple Palo Alto Networks NGFW instances, each located in a different AZ. It uses health probes to continuously monitor the status of each firewall. If a firewall instance or an entire AZ fails, the health probe detects the failure, and the load balancer automatically stops sending traffic to the unhealthy instance, redirecting it to the remaining healthy firewalls in other AZs. This architecture provides seamless failover and resilience.

A. Deploying Ansible scripts for zone-specific scaling: Ansible is an automation tool used for configuration and deployment, not the architectural mechanism that provides high availability and failover.

B. Implementing Terraform templates for redundancy within one availability zone: This option is incorrect because the question explicitly requires a solution for HA across multiple availability zones, not within a single one.

D. Configuring active/active HA: Traditional Palo Alto Networks active/active HA relies on Layer 2 connectivity for state synchronization, which is not available across different cloud availability zones. Cloud HA architectures depend on load balancers.

1. Palo Alto Networks - VM-Series on AWS Reference Architecture Guide: "To provide high availability for the VM-Series firewalls

you deploy an active/active pair of firewalls that are fronted by an Elastic Load Balancer (ELB). The ELB distributes traffic between the firewalls and provides health checks to ensure that traffic is only sent to a healthy firewall." (Section: Security VPC with an Internet Gateway

subsection: High Availability)

2. Palo Alto Networks - VM-Series on Azure Deployment Guide: "For high availability and resiliency

you can deploy the VM-Series firewalls in an active/active configuration across multiple availability zones. The Azure Load Balancer distributes sessions between the firewalls and uses health probes to detect firewall failure." (Chapter: VM-Series Firewall for Azure Reference Architecture

Section: High Availability for the VM-Series Firewall on Azure)

3. Palo Alto Networks - High Availability for VM-Series Firewall on AWS: "The VM-Series firewall on AWS supports high availability (HA) between instances deployed in different Availability Zones (AZs). This solution uses AWS services such as Elastic Load Balancing (ELB)

Lambda

and S3 to provide a resilient firewall solution." (Document ID: 86453

Section: Overview)