NSX Precheck shows open alarm for BGP, but no BGP alarms are showing in NSX UI

Products

• VMware NSX

Issue/Introduction

• NSX upgrades may be halted due to an alarms stating that BGP is Down even though BGP is up.
• If the upgrade is performed from the SDDC or VCF UI, you may see this as an error that stops the upgrade from continuing.
• You will see this error in upgrade pre-checks from the NSX UI regardless of where the upgrade was started from.
• The main alarms page in NSX UI does not show any current BGP alarms.
• Performing an elastic search of the Edge UUID that is generating the alarm will show open alarms for BGP Down.
• BGP is working as expected.

Environment

• VMware NSX
• VMware NSX-T Data Center

Cause

When BGP goes down, the alarms are generated for all BGP links, including inter-SR BGP, regardless of its state. When BGP is restored, external alarms will be cleared due to state change, but if inter-SR BGP did not change state, the alarms will not clear.  

Inter-SR BGP alarms do not appear in the NSX alarm UI.

Resolution

1. Navigate to the Network section of the NSX UI, and go to the Tier-0 gateway section.
   
2. Click the ellipse next to the affected T0 and select Edit.
   
3. Navigate to the BGP section and toggle the Inter SR iBGP option off.
   
4. Click on the Save button.
   
5. Repeat steps 2 - 4, toggling Inter SR iBGP to On.
6. Rerun the pre-checks for the edges to verify the issue is resolved.