🚀 Proxmox VE P13 – How to Setup High Availability (2-Node Cluster + NAS) | Failover Test

High Availability (HA) is one of the most powerful features in Proxmox VE, allowing virtual machines to automatically restart on another node if a failure occurs.

In this tutorial, we guide you through the complete process of setting up Proxmox HA on a two-node cluster using NAS shared storage.

You will learn how to:

• Configure HA in a 2-node Proxmox cluster

• Use NAS (NFS) as shared storage

• Set quorum votes correctly

• Add VM to HA group

• Simulate a real hardware failure

• Test automatic failover behavior

By the end of this guide, you will have a fully functional HA environment capable of handling node failures automatically.

🧪 Lab Environment

I/ HA Configuration – 2 Nodes

Step 0: Mount storage NFS

Both nodes must use shared storage.

In this lab, we use:

• NAS Synology with shared NFS folder

• Storage mounted on both PVE01 and PVE02

Alternative shared storage options:

• SMB

• OneDrive

• Other centralized storage

Video guide to mount NFS:
https://youtu.be/oXagwrTRzM8

Step 1: Move disk VM to storage NFS

Move the Windows10 VM disk from local storage to the mounted NFS storage.

This ensures the VM can run on either node.

Step 2: Set Vote for PVE02

Initially, both nodes have a vote number of 1 (Cluster Information).

In a 2-node cluster, quorum must be adjusted manually.
In clusters with 3 or more nodes, the system automatically handles votes.

Open the shell of pve01 and run:

Backup and edit corosync configuration:

Edit:

Save the file:

Ctrl + O → Enter
Exit: Ctrl + X

Replace original file:

Check vote number after setup in Cluster Information.

Step 3: Create HA

Add VM resource:

Add node HA (configure via GUI or group policy as needed).

Remove VM from HA (optional):

Restart HA service:

At this stage, HA is enabled.

II/ Simulate PVE01 FAIL Disaster

Now we simulate a real hardware failure.

Demo STOP pve01 (simulate main node hardware failure).

Login to pve02 (backup) and monitor.

After approximately 3–5 minutes:

• VM Windows10 automatically moves to PVE02

• VM automatically starts

This demonstrates Proxmox HA failover capability.

Step 1: Handle Physical Server PVE01

After repairing hardware, reconnect and power on Server PVE01.

If HA node priority was configured:

• PVE01 priority = 2

• PVE02 lower priority

VM will automatically migrate back to PVE01 once it becomes available.

This behavior ensures workload runs on preferred primary node.

Step 2: Restart service system PVE01 (main)

Restart services:

Ensure cluster and HA manager services are fully operational.

Step 3: Migrate VM Windows10 back to PVE01

If both nodes have equal priority (priority set 1):

Manual migration can be performed during low-traffic hours.

This ensures minimal service disruption.

Step 4: Restart service system PVE02 (backup)

Restart services:

Both nodes should now be fully synchronized.

III/ If PVE01 Cannot Be Repaired – Replace with PVE03

In case the main node cannot be recovered:

Step 1: Shutdown all VMs of PVE02

Ensure no running workloads before cluster modification.

Step 2: Remove cluster group

Remove existing cluster configuration.

Step 3: Share NFS

On NAS:

• Add IP permission for PVE03

• Or configure PVE03 to use the same IP as original PVE01

Ensure NFS access is identical.

Step 4: On PVE03, add storage NFS NAS

Mount NFS storage on new node.

Step 5: Create cluster group for PVE02 and PVE03

Recreate cluster.

Create HA group.

Set number of votes.

Cluster is restored with new hardware.

🔐 Best Practices for 2-Node HA

✔ Always use shared storage
✔ Configure vote manually for 2-node cluster
✔ Set priority for primary node
✔ Test failover before production deployment
✔ Monitor HA status regularly

For production:

• Consider adding QDevice for better quorum stability

• Use dedicated network for corosync

• Monitor HA logs for anomalies

🎯 Conclusion

Setting up Proxmox HA in a 2-node cluster with NAS storage provides enterprise-level resilience even in small infrastructure environments.

In this guide, you have:

• Configured HA

• Adjusted quorum votes

• Added VM resource

• Simulated real disaster failover

• Tested recovery process

• Rebuilt cluster after hardware replacement

Understanding HA failover behavior is critical for any system administrator managing virtualization infrastructure.

This tutorial not only teaches configuration steps but also demonstrates real-world disaster recovery scenarios.