Unable to apply Tier-0 Active-Standby configuration to an Edge for set-ups not running BGP with Route-Maps configured
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Unable to apply Tier-0 Active-Standby configuration to an Edge for set-ups not running BGP with Route-Maps configured

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Article ID: 306206

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Updated On:

Products

VMware NSX Networking VMware NSX

Issue/Introduction

Symptoms:


This issue applies only to the following scenarios:

  • NSX-T 2.4.0, 2.4.1, 2.4.2
  • Tier-0 is configured in Active-Standby
  • Only static routes in use.  No BGP configuration
  • Route-Maps are configured
  • Customers upgrading to 2.4.x or greenfield deployment running 2.4.x with above scenario will be impacted.



During the failed state:

  • Tier-0 static routes are missing (including the default route)
  • What should be Tier-1 learned routes are missing, only Tier-0 connected routes are present
  • FRR errors appear in the edge /var/log/syslog files, including:
    • INFO "Coverting routing proto to frrcfg and pushing it to FRR"
    • ERROR "No file /config/vmware/edge/frr/frr-additional-config.txt"
    • ERROR "Unable to push the config to FRR"
    • ERROR "Error in applying the config to FRR"

 

Environment

VMware NSX-T Data Center
VMware NSX-T Data Center 2.x

Cause

In NSX-T, route maps are configured with several criterion, one of which is called "as-prepend." When no BGP AS is configured, the Management Plane tries to send a configuration to the Edge with command "set as-path prepend" without specifying the AS numbers. When the Edge Node tries to apply this configuration to the Routing Daemon, it fails resulting in no routes being applied.

Resolution


This issue will be fixed in NSX-T 2.5, and NSX-T 2.4.3


Workaround:


One of the following workarounds can be used to correct the problem:

  1. Edit the BGP configuration and add dummy AS number. (BGP does not need to be enabled.)
  2. Delete the Route-MAP if it's not required or used by the route-redistribution.