HA Clustering Best Practices and Provisioning

Follow provisioning requirements and best practices for HA clustering.
These are the provisioning requirements and best practices for HA clustering.
  • Provisioning Requirements and Best Practices
    • HA cluster members must be the same firewall model and run the same PAN-OS
      When upgrading, firewall members will continue to synchronize sessions with one member at a different version.
    • It is highly recommended and a best practice to use Panorama to provision HA cluster members to keep all configuration and policies synchronized among all cluster members.
    • HA cluster members must be licensed for the same components to ensure consistent policy enforcement and content inspection capabilities.
    • The licenses must expire at the same time to prevent mismatched licenses and loss of functionality.
    • All cluster members should be running with the same version of dynamic Content Updates for consistent security enforcement.
    • HA cluster members must share the same zone names in order for sessions to successfully fail over to another cluster member. For example, suppose sessions going to an ingress zone named
      are dropped because the link is down. For those sessions to fail over to an HA firewall peer in the cluster, that peer must also have a zone named
    • Client-to-server and server-to-client flows must go back to the same firewall under normal (non-failure) conditions in order for security content scanning to occur. Asymmetric traffic won’t be dropped, but it cannot be scanned for security purposes.
  • Session Synchronization Best Practices
    • Dedicated HA communication interfaces should be used over dataplane interfaces. HSCI interfaces aren’t used for HA4. This allows separation of HA pair and cluster session synchronization to ensure maximum bandwidth and reliability for session syncing.
    • HA4 should be adequately sized if you use dataplane interfaces. This ensures best effort session state synchronizing between cluster members.
    • Best practice is to have a dedicated cluster network for the HA4 communications link to ensure adequate bandwidth and non-congested, low-latency connections between cluster members.
    • Architect your networks and perform traffic engineering to avoid possible race conditions, in which a network steers traffic from the session owner to a cluster member before the session is successfully synced between the firewalls. Layer2 HA4 connections must have sufficient bandwidth and low latency to allow timely synchronization between HA members. The HA4 latency must be lower than the latency incurred when the peering devices switch traffic between cluster members.
    • Architect your networks to minimize asymmetric flows. Session setup requires one cluster member to see the complete TCP three-way handshake.
  • Health Check Best Practices
    • On HA pairs in a cluster, configure an Active/Passive pair with HA backup communication links for HA1, HA2, and HA4. Configure an Active/Active pair with HA backup communications links for HA1, HA2, HA3, and HA4.
    • Configure HA4 backup links on all cluster members.

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