Eric Sloof

Introduction

Maintaining the availability of the NSX-T management cluster is crucial for ensuring the stability and performance of your virtualized network environment. This blog post will explore strategies to ensure high availability (HA) of NSX-T managers, outline the recovery process during failures, and discuss best practices for disaster recovery.

NSX-T Management Cluster Overview

The NSX-T management cluster typically consists of three nodes. This configuration ensures redundancy and fault tolerance. If one node fails, the cluster retains quorum, and normal operations continue. However, the failure of two nodes can disrupt management operations, requiring swift recovery actions.

High Availability in NSX-T Management Cluster

1. Quorum Maintenance:

• The management cluster needs at least two out of three nodes operational to maintain quorum. This ensures that the NSX Manager UI and related services remain available.
• If a node fails, the remaining two nodes can still communicate and manage the environment, preventing downtime.

2. Node Failures and Impact:

• Single Node Failure: The cluster continues to function normally with two nodes.
• Two Nodes Failure: The cluster loses quorum, and the NSX Manager UI becomes unavailable. Management operations via CLI and API will also fail.

Recovery Strategies

When a majority of the nodes fail, swift action is required to restore the cluster to a functional state.

1. Deploying a New Manager Node:

• Deploy a new manager node as a fourth member of the existing cluster.
• Use the CLI command detach node <node-uuid> or the API endpoint /api/v1/cluster/<node-uuid>?action=remove_node to remove the failed node from the cluster.
• This command should be executed from one of the healthy nodes.

2. Deactivating the Cluster (Optional):

• Run the deactivate cluster command on the active node to form a single-node cluster.
• Add new nodes to restore the cluster to its three-node configuration.

Best Practices for Disaster Recovery

1. Regular Backups:

• Schedule regular backups of the NSX Manager configurations to facilitate quick recovery.
• Store backups securely and ensure they are easily accessible during a disaster recovery scenario.

2. Geographical Redundancy:

• Deploy NSX Managers across multiple sites to ensure geographical redundancy.
• In case of a site failure, the other site can take over management operations with minimal disruption.

3. Proactive Monitoring:

• Use NSX-T's built-in monitoring tools and integrate with third-party solutions to continuously monitor the health of the management cluster.
• Early detection of issues can prevent major failures and reduce downtime.

4. Disaster Recovery Sites:

• Prepare a disaster recovery site with standby NSX Managers configured to recover from backups.
• This setup allows for quick restoration and ensures continuity of operations in case of a primary site failure.

Conclusion

Ensuring the high availability and disaster recovery of your NSX-T management cluster is essential for maintaining a robust and resilient virtual network environment. By following best practices for node management, deploying a geographically redundant setup, and maintaining regular backups, you can minimize downtime and ensure swift recovery from failures.

For a deeper dive into the technical details, check out these resources:

• VMware NSX-T Data Center Documentation
• Backup and Restore of VMware Cloud Foundation
• NSX Manager cluster is DOWN or UNAVAILABLE if all nodes part of the the NSX Manager cluster is down or majority nodes are down

In this video, I'll demonstrate these concepts in action, explore various failure scenarios, and discuss disaster recovery strategies in detail. You can obtain a copy of the original Excalidraw whiteboard file along with the presentation slides in both PDF and PowerPoint formats from GitHub.