Tier 1 connected route missing from Tier 0 route table on Active Edge which is present on the Standby Edge
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Tier 1 connected route missing from Tier 0 route table on Active Edge which is present on the Standby Edge

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Article ID: 400995

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Updated On:

Products

VMware NSX

Issue/Introduction

  • You may have recently rebooted or upgraded an NSX Edge node.
  • A T1C (Tier-1 Connected) route is not present in the Tier-0 routing table in the Active Tier-0 Edge
  • The T1C route is present in the Tier-0 routing table in the Standby Tier-0 Edge.
  • The following messages may be seen in /var/log/frr/frr.log and also in /var/log/syslog

2025/02/19 17:13:40.190834 ZEBRA: 0:###.###.###.###/## doesn't exist in rib
2025/02/19 17:13:53.299993 OSPF: [EC #########] INTERFACE_STATE: Cannot find IF downlink-<id> in VRF 0
2025/02/19 17:14:05.404121 STATIC: Static Route using downlink-<id> interface not installed because the interface does not exist in specified vrf

  • This issue may also be observed in an Active/Active T0 deployment.

Environment

  • VMware NSX
  • VMware NSX-T Data Center

Cause

Routing controller reads interface kernel notifications via netlink socket. During an Edge reboot, netlink notifications might get dropped/missed. This leads to missed configuration on the interfaces in comparison to the kernel.

Resolution

This is a known issue impacting VMware NSX.

Workaround 1:
To recover the missing IPv4/IPv6 addresses, the interfaces can be rescanned using the below command in the edge node CLI as admin user:

Edge> get logical-routers
Edge> vrf <vrf_id of SERVICE_ROUTER_TIER0>
Edge(tier0_sr)> set debug
Edge(tier0_sr)> start rescan interfaces
Edge(tier0_sr)> exit

NOTE: For VMware NSX versions prior to 4.1.2, do not use the workaround on EVPN enabled setups.

Workaround 2:

  1. Place the Edge into Maintenance Mode.
  2. Take the Edge out of Maintenance Mode.

Workaround 3:

  • Reboot the Edge.

Additional Information

Other symptoms relative to this issue are detailed in the following KB:

VMware NSX Edge routing fails due to the corresponding interface/address missing in zclients

For additional information related to specific scenarios impacting BGP neighbors failing to establish due to IPv4/IPv6 addresses missing on NSX-T edge node interfaces, please refer to the following KB:

BGP neighbors fail to establish due to IPv4/IPv6 addresses missing on NSX-T edge node interfaces

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