Troubleshooting BGP in Red Hat OpenStack Platform

Diagnosing problems in a Red Hat OpenStack Platform environment that uses BGP begins with examining logs and querying FRR components with VTY shell.

Log Locations

The key log files for troubleshooting BGP issues are:

  • OVN BGP Agent logs: Located on Compute and Networker nodes

    /var/log/containers/stdouts/ovn_bgp_agent.log

  • FRR component logs: Located on all nodes where FRR is running

    /var/log/containers/frr/frr.log

Using VTY Shell for Troubleshooting

VTY shell allows interaction with FRR daemons to diagnose BGP routing issues.

Accessing VTY Shell

  1. Log in to the node where you need to troubleshoot BGP

  2. Enter the FRR container:

    $ sudo podman exec -it frr bash

  3. You can use VTY shell in two different modes:

    • Interactive mode:

      $ sudo vtysh
> show bgp summary

    • Direct mode:

      $ sudo vtysh -c 'show bgp summary'

Useful Troubleshooting Commands

The following commands help diagnose common BGP issues:

  • Display BGP routing tables:

    # For IPv4
> show ip bgp <IPv4_address> | all

# For IPv6 (omit the 'ip' argument)
> show bgp <IPv6_address> | all

  • Show routes advertised to a peer:

    > show ip bgp neighbors <router-ID> advertised-routes

  • Show routes received from a peer:

    > show ip bgp neighbors <router-ID> received-routes

  • Check BGP peer status:

    > show bgp summary

  • Verify BGP configuration:

    > show running-config

Common BGP Issues

Here are some common issues you might encounter and how to address them:

  1. BGP Peers Not Establishing Connection

    • Check IP connectivity between peers

    • Verify ASN configuration matches on both sides

    • Check for firewall rules blocking BGP port (TCP 179)

    • Examine logs for capability negotiation issues

  2. Routes Not Being Advertised

    • Verify the OVN BGP agent is running

    • Check if IP addresses are added to the bgp-nic interface

    • Inspect FRR configuration for proper route redistribution

    • Check for route filtering that might prevent advertisement

  3. Traffic Not Reaching VMs

    • Verify OVS flow rules are correctly installed

    • Check IP rules and routing table entries

    • Ensure ARP/NDP proxy is enabled on the provider bridge

    • Confirm VRF configuration is correct

  4. Slow Convergence After Failures

    • Check if BFD is enabled and configured correctly

    • Verify timers are set appropriately

    • Inspect BGP graceful restart configuration

    • Check for any route dampening that might delay reconvergence