NSX appliance may fail to boot after a storage outage

Products

• VMware NSX Networking

Issue/Introduction

Underlying storage infrastructure issues may impact on NSX appliances.

An alarm may indicate an appliance is in read-only mode and should be rebooted.

If the appliance still has a problem after reboot, it may boot into emergency mode similar to this example
 

You are in emergency mode. 
After logging in, type "journalctl -xb" to view system logs, 
"systemctl reboot" to reboot, "systemctl default" 
or "exit" to boot into default mode". 
Give root password for maintenance
(or press Control-D to continue):

Environment

VMware NSX 4.1.0

Resolution

NSX appliances that will not boot should be recovered following VMware documentation.

NSX Managers: Restore from backup

• 3.x Restore a Backup
• 4.x Restore a Backup

NSX Edges: Redeploy the Edge or deploy a new Edge and replace the impacted node

• 3.x: Replace an NSX Edge Transport Node Using the NSX Manager UI
• 4.x: Replace an NSX Edge Transport Node Using the NSX Manager UI

It is not supported to recover NSX appliances via alternative methods such as fsck etc.