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Setting the MetalLB logging levels

MetalLB uses FRRouting (FRR) in a container with the default setting of info generates a lot of logging. You can control the verbosity of the logs generated by setting the logLevel as illustrated in this example.

Gain a deeper insight into MetalLB by setting the logLevel to debug as follows:

Prerequisites
  • You have access to the cluster as a user with the cluster-admin role.

  • You have installed the OpenShift CLI (oc).

Procedure
  1. Create a file, such as setdebugloglevel.yaml, with content like the following example:

    apiVersion: metallb.io/v1beta1
    kind: MetalLB
    metadata:
      name: metallb
      namespace: metallb-system
    spec:
      logLevel: debug
      nodeSelector:
        node-role.kubernetes.io/worker: ""
  2. Apply the configuration:

    $ oc replace -f setdebugloglevel.yaml

    Use oc replace as the understanding is the metallb CR is already created and here you are changing the log level.

  3. Display the names of the speaker pods:

    $ oc get -n metallb-system pods -l component=speaker
    Example output
    NAME                    READY   STATUS    RESTARTS   AGE
    speaker-2m9pm           4/4     Running   0          9m19s
    speaker-7m4qw           3/4     Running   0          19s
    speaker-szlmx           4/4     Running   0          9m19s

    Speaker and controller pods are recreated to ensure the updated logging level is applied. The logging level is modified for all the components of MetalLB.

  4. View the speaker logs:

    $ oc logs -n metallb-system speaker-7m4qw -c speaker
    Example output
    {"branch":"main","caller":"main.go:92","commit":"3d052535","goversion":"gc / go1.17.1 / amd64","level":"info","msg":"MetalLB speaker starting (commit 3d052535, branch main)","ts":"2022-05-17T09:55:05Z","version":""}
    {"caller":"announcer.go:110","event":"createARPResponder","interface":"ens4","level":"info","msg":"created ARP responder for interface","ts":"2022-05-17T09:55:05Z"}
    {"caller":"announcer.go:119","event":"createNDPResponder","interface":"ens4","level":"info","msg":"created NDP responder for interface","ts":"2022-05-17T09:55:05Z"}
    {"caller":"announcer.go:110","event":"createARPResponder","interface":"tun0","level":"info","msg":"created ARP responder for interface","ts":"2022-05-17T09:55:05Z"}
    {"caller":"announcer.go:119","event":"createNDPResponder","interface":"tun0","level":"info","msg":"created NDP responder for interface","ts":"2022-05-17T09:55:05Z"}
    I0517 09:55:06.515686      95 request.go:665] Waited for 1.026500832s due to client-side throttling, not priority and fairness, request: GET:https://172.30.0.1:443/apis/operators.coreos.com/v1alpha1?timeout=32s
    {"Starting Manager":"(MISSING)","caller":"k8s.go:389","level":"info","ts":"2022-05-17T09:55:08Z"}
    {"caller":"speakerlist.go:310","level":"info","msg":"node event - forcing sync","node addr":"10.0.128.4","node event":"NodeJoin","node name":"ci-ln-qb8t3mb-72292-7s7rh-worker-a-vvznj","ts":"2022-05-17T09:55:08Z"}
    {"caller":"service_controller.go:113","controller":"ServiceReconciler","enqueueing":"openshift-kube-controller-manager-operator/metrics","epslice":"{\"metadata\":{\"name\":\"metrics-xtsxr\",\"generateName\":\"metrics-\",\"namespace\":\"openshift-kube-controller-manager-operator\",\"uid\":\"ac6766d7-8504-492c-9d1e-4ae8897990ad\",\"resourceVersion\":\"9041\",\"generation\":4,\"creationTimestamp\":\"2022-05-17T07:16:53Z\",\"labels\":{\"app\":\"kube-controller-manager-operator\",\"endpointslice.kubernetes.io/managed-by\":\"endpointslice-controller.k8s.io\",\"kubernetes.io/service-name\":\"metrics\"},\"annotations\":{\"endpoints.kubernetes.io/last-change-trigger-time\":\"2022-05-17T07:21:34Z\"},\"ownerReferences\":[{\"apiVersion\":\"v1\",\"kind\":\"Service\",\"name\":\"metrics\",\"uid\":\"0518eed3-6152-42be-b566-0bd00a60faf8\",\"controller\":true,\"blockOwnerDeletion\":true}],\"managedFields\":[{\"manager\":\"kube-controller-manager\",\"operation\":\"Update\",\"apiVersion\":\"discovery.k8s.io/v1\",\"time\":\"2022-05-17T07:20:02Z\",\"fieldsType\":\"FieldsV1\",\"fieldsV1\":{\"f:addressType\":{},\"f:endpoints\":{},\"f:metadata\":{\"f:annotations\":{\".\":{},\"f:endpoints.kubernetes.io/last-change-trigger-time\":{}},\"f:generateName\":{},\"f:labels\":{\".\":{},\"f:app\":{},\"f:endpointslice.kubernetes.io/managed-by\":{},\"f:kubernetes.io/service-name\":{}},\"f:ownerReferences\":{\".\":{},\"k:{\\\"uid\\\":\\\"0518eed3-6152-42be-b566-0bd00a60faf8\\\"}\":{}}},\"f:ports\":{}}}]},\"addressType\":\"IPv4\",\"endpoints\":[{\"addresses\":[\"10.129.0.7\"],\"conditions\":{\"ready\":true,\"serving\":true,\"terminating\":false},\"targetRef\":{\"kind\":\"Pod\",\"namespace\":\"openshift-kube-controller-manager-operator\",\"name\":\"kube-controller-manager-operator-6b98b89ddd-8d4nf\",\"uid\":\"dd5139b8-e41c-4946-a31b-1a629314e844\",\"resourceVersion\":\"9038\"},\"nodeName\":\"ci-ln-qb8t3mb-72292-7s7rh-master-0\",\"zone\":\"us-central1-a\"}],\"ports\":[{\"name\":\"https\",\"protocol\":\"TCP\",\"port\":8443}]}","level":"debug","ts":"2022-05-17T09:55:08Z"}
  5. View the FRR logs:

    $ oc logs -n metallb-system speaker-7m4qw -c frr
    Example output
    Started watchfrr
    2022/05/17 09:55:05 ZEBRA: client 16 says hello and bids fair to announce only bgp routes vrf=0
    2022/05/17 09:55:05 ZEBRA: client 31 says hello and bids fair to announce only vnc routes vrf=0
    2022/05/17 09:55:05 ZEBRA: client 38 says hello and bids fair to announce only static routes vrf=0
    2022/05/17 09:55:05 ZEBRA: client 43 says hello and bids fair to announce only bfd routes vrf=0
    2022/05/17 09:57:25.089 BGP: Creating Default VRF, AS 64500
    2022/05/17 09:57:25.090 BGP: dup addr detect enable max_moves 5 time 180 freeze disable freeze_time 0
    2022/05/17 09:57:25.090 BGP: bgp_get: Registering BGP instance (null) to zebra
    2022/05/17 09:57:25.090 BGP: Registering VRF 0
    2022/05/17 09:57:25.091 BGP: Rx Router Id update VRF 0 Id 10.131.0.1/32
    2022/05/17 09:57:25.091 BGP: RID change : vrf VRF default(0), RTR ID 10.131.0.1
    2022/05/17 09:57:25.091 BGP: Rx Intf add VRF 0 IF br0
    2022/05/17 09:57:25.091 BGP: Rx Intf add VRF 0 IF ens4
    2022/05/17 09:57:25.091 BGP: Rx Intf address add VRF 0 IF ens4 addr 10.0.128.4/32
    2022/05/17 09:57:25.091 BGP: Rx Intf address add VRF 0 IF ens4 addr fe80::c9d:84da:4d86:5618/64
    2022/05/17 09:57:25.091 BGP: Rx Intf add VRF 0 IF lo
    2022/05/17 09:57:25.091 BGP: Rx Intf add VRF 0 IF ovs-system
    2022/05/17 09:57:25.091 BGP: Rx Intf add VRF 0 IF tun0
    2022/05/17 09:57:25.091 BGP: Rx Intf address add VRF 0 IF tun0 addr 10.131.0.1/23
    2022/05/17 09:57:25.091 BGP: Rx Intf address add VRF 0 IF tun0 addr fe80::40f1:d1ff:feb6:5322/64
    2022/05/17 09:57:25.091 BGP: Rx Intf add VRF 0 IF veth2da49fed
    2022/05/17 09:57:25.091 BGP: Rx Intf address add VRF 0 IF veth2da49fed addr fe80::24bd:d1ff:fec1:d88/64
    2022/05/17 09:57:25.091 BGP: Rx Intf add VRF 0 IF veth2fa08c8c
    2022/05/17 09:57:25.091 BGP: Rx Intf address add VRF 0 IF veth2fa08c8c addr fe80::6870:ff:fe96:efc8/64
    2022/05/17 09:57:25.091 BGP: Rx Intf add VRF 0 IF veth41e356b7
    2022/05/17 09:57:25.091 BGP: Rx Intf address add VRF 0 IF veth41e356b7 addr fe80::48ff:37ff:fede:eb4b/64
    2022/05/17 09:57:25.092 BGP: Rx Intf add VRF 0 IF veth1295c6e2
    2022/05/17 09:57:25.092 BGP: Rx Intf address add VRF 0 IF veth1295c6e2 addr fe80::b827:a2ff:feed:637/64
    2022/05/17 09:57:25.092 BGP: Rx Intf add VRF 0 IF veth9733c6dc
    2022/05/17 09:57:25.092 BGP: Rx Intf address add VRF 0 IF veth9733c6dc addr fe80::3cf4:15ff:fe11:e541/64
    2022/05/17 09:57:25.092 BGP: Rx Intf add VRF 0 IF veth336680ea
    2022/05/17 09:57:25.092 BGP: Rx Intf address add VRF 0 IF veth336680ea addr fe80::94b1:8bff:fe7e:488c/64
    2022/05/17 09:57:25.092 BGP: Rx Intf add VRF 0 IF vetha0a907b7
    2022/05/17 09:57:25.092 BGP: Rx Intf address add VRF 0 IF vetha0a907b7 addr fe80::3855:a6ff:fe73:46c3/64
    2022/05/17 09:57:25.092 BGP: Rx Intf add VRF 0 IF vethf35a4398
    2022/05/17 09:57:25.092 BGP: Rx Intf address add VRF 0 IF vethf35a4398 addr fe80::40ef:2fff:fe57:4c4d/64
    2022/05/17 09:57:25.092 BGP: Rx Intf add VRF 0 IF vethf831b7f4
    2022/05/17 09:57:25.092 BGP: Rx Intf address add VRF 0 IF vethf831b7f4 addr fe80::f0d9:89ff:fe7c:1d32/64
    2022/05/17 09:57:25.092 BGP: Rx Intf add VRF 0 IF vxlan_sys_4789
    2022/05/17 09:57:25.092 BGP: Rx Intf address add VRF 0 IF vxlan_sys_4789 addr fe80::80c1:82ff:fe4b:f078/64
    2022/05/17 09:57:26.094 BGP: 10.0.0.1 [FSM] Timer (start timer expire).
    2022/05/17 09:57:26.094 BGP: 10.0.0.1 [FSM] BGP_Start (Idle->Connect), fd -1
    2022/05/17 09:57:26.094 BGP: Allocated bnc 10.0.0.1/32(0)(VRF default) peer 0x7f807f7631a0
    2022/05/17 09:57:26.094 BGP: sendmsg_zebra_rnh: sending cmd ZEBRA_NEXTHOP_REGISTER for 10.0.0.1/32 (vrf VRF default)
    2022/05/17 09:57:26.094 BGP: 10.0.0.1 [FSM] Waiting for NHT
    2022/05/17 09:57:26.094 BGP: bgp_fsm_change_status : vrf default(0), Status: Connect established_peers 0
    2022/05/17 09:57:26.094 BGP: 10.0.0.1 went from Idle to Connect
    2022/05/17 09:57:26.094 BGP: 10.0.0.1 [FSM] TCP_connection_open_failed (Connect->Active), fd -1
    2022/05/17 09:57:26.094 BGP: bgp_fsm_change_status : vrf default(0), Status: Active established_peers 0
    2022/05/17 09:57:26.094 BGP: 10.0.0.1 went from Connect to Active
    2022/05/17 09:57:26.094 ZEBRA: rnh_register msg from client bgp: hdr->length=8, type=nexthop vrf=0
    2022/05/17 09:57:26.094 ZEBRA: 0: Add RNH 10.0.0.1/32 type Nexthop
    2022/05/17 09:57:26.094 ZEBRA: 0:10.0.0.1/32: Evaluate RNH, type Nexthop (force)
    2022/05/17 09:57:26.094 ZEBRA: 0:10.0.0.1/32: NH has become unresolved
    2022/05/17 09:57:26.094 ZEBRA: 0: Client bgp registers for RNH 10.0.0.1/32 type Nexthop
    2022/05/17 09:57:26.094 BGP: VRF default(0): Rcvd NH update 10.0.0.1/32(0) - metric 0/0 #nhops 0/0 flags 0x6
    2022/05/17 09:57:26.094 BGP: NH update for 10.0.0.1/32(0)(VRF default) - flags 0x6 chgflags 0x0 - evaluate paths
    2022/05/17 09:57:26.094 BGP: evaluate_paths: Updating peer (10.0.0.1(VRF default)) status with NHT
    2022/05/17 09:57:30.081 ZEBRA: Event driven route-map update triggered
    2022/05/17 09:57:30.081 ZEBRA: Event handler for route-map: 10.0.0.1-out
    2022/05/17 09:57:30.081 ZEBRA: Event handler for route-map: 10.0.0.1-in
    2022/05/17 09:57:31.104 ZEBRA: netlink_parse_info: netlink-listen (NS 0) type RTM_NEWNEIGH(28), len=76, seq=0, pid=0
    2022/05/17 09:57:31.104 ZEBRA: 	Neighbor Entry received is not on a VLAN or a BRIDGE, ignoring
    2022/05/17 09:57:31.105 ZEBRA: netlink_parse_info: netlink-listen (NS 0) type RTM_NEWNEIGH(28), len=76, seq=0, pid=0
    2022/05/17 09:57:31.105 ZEBRA: 	Neighbor Entry received is not on a VLAN or a BRIDGE, ignoring

FRRouting (FRR) log levels

The following table describes the FRR logging levels.

Table 1. Log levels
Log level Description

all

Supplies all logging information for all logging levels.

debug

Information that is diagnostically helpful to people. Set to debug to give detailed troubleshooting information.

info

Provides information that always should be logged but under normal circumstances does not require user intervention. This is the default logging level.

warn

Anything that can potentially cause inconsistent MetalLB behaviour. Usually MetalLB automatically recovers from this type of error.

error

Any error that is fatal to the functioning of MetalLB. These errors usually require administrator intervention to fix.

none

Turn off all logging.

Troubleshooting BGP issues

The BGP implementation that Red Hat supports uses FRRouting (FRR) in a container in the speaker pods. As a cluster administrator, if you need to troubleshoot BGP configuration issues, you need to run commands in the FRR container.

Prerequisites
  • You have access to the cluster as a user with the cluster-admin role.

  • You have installed the OpenShift CLI (oc).

Procedure
  1. Display the names of the speaker pods:

    $ oc get -n metallb-system pods -l component=speaker
    Example output
    NAME            READY   STATUS    RESTARTS   AGE
    speaker-66bth   4/4     Running   0          56m
    speaker-gvfnf   4/4     Running   0          56m
    ...
  2. Display the running configuration for FRR:

    $ oc exec -n metallb-system speaker-66bth -c frr -- vtysh -c "show running-config"
    Example output
    Building configuration...
    
    Current configuration:
    !
    frr version 7.5.1_git
    frr defaults traditional
    hostname some-hostname
    log file /etc/frr/frr.log informational
    log timestamp precision 3
    service integrated-vtysh-config
    !
    router bgp 64500  (1)
     bgp router-id 10.0.1.2
     no bgp ebgp-requires-policy
     no bgp default ipv4-unicast
     no bgp network import-check
     neighbor 10.0.2.3 remote-as 64500  (2)
     neighbor 10.0.2.3 bfd profile doc-example-bfd-profile-full  (3)
     neighbor 10.0.2.3 timers 5 15
     neighbor 10.0.2.4 remote-as 64500
     neighbor 10.0.2.4 bfd profile doc-example-bfd-profile-full
     neighbor 10.0.2.4 timers 5 15
     !
     address-family ipv4 unicast
      network 203.0.113.200/30   (4)
      neighbor 10.0.2.3 activate
      neighbor 10.0.2.3 route-map 10.0.2.3-in in
      neighbor 10.0.2.4 activate
      neighbor 10.0.2.4 route-map 10.0.2.4-in in
     exit-address-family
     !
     address-family ipv6 unicast
      network fc00:f853:ccd:e799::/124
      neighbor 10.0.2.3 activate
      neighbor 10.0.2.3 route-map 10.0.2.3-in in
      neighbor 10.0.2.4 activate
      neighbor 10.0.2.4 route-map 10.0.2.4-in in
     exit-address-family
    !
    route-map 10.0.2.3-in deny 20
    !
    route-map 10.0.2.4-in deny 20
    !
    ip nht resolve-via-default
    !
    ipv6 nht resolve-via-default
    !
    line vty
    !
    bfd
     profile doc-example-bfd-profile-full
      transmit-interval 35
      receive-interval 35
      passive-mode
      echo-mode
      echo-interval 35
      minimum-ttl 10
     !
    !
    end
    1 The router bgp section indicates the ASN for MetalLB.
    2 Confirm that a neighbor <ip-address> remote-as <peer-ASN> line exists for each BGP peer custom resource that you added.
    3 If you configured BFD, confirm that the BFD profile is associated with the correct BGP peer and that the BFD profile appears in the command output.
    4 Confirm that the network <ip-address-range> lines match the IP address ranges that you specified in address pool custom resources that you added.
  3. Display the BGP summary:

    $ oc exec -n metallb-system speaker-66bth -c frr -- vtysh -c "show bgp summary"
    Example output
    IPv4 Unicast Summary:
    BGP router identifier 10.0.1.2, local AS number 64500 vrf-id 0
    BGP table version 1
    RIB entries 1, using 192 bytes of memory
    Peers 2, using 29 KiB of memory
    
    Neighbor        V         AS   MsgRcvd   MsgSent   TblVer  InQ OutQ  Up/Down State/PfxRcd   PfxSnt
    10.0.2.3        4      64500       387       389        0    0    0 00:32:02            0        1  (1)
    10.0.2.4        4      64500         0         0        0    0    0    never       Active        0  (2)
    
    Total number of neighbors 2
    
    IPv6 Unicast Summary:
    BGP router identifier 10.0.1.2, local AS number 64500 vrf-id 0
    BGP table version 1
    RIB entries 1, using 192 bytes of memory
    Peers 2, using 29 KiB of memory
    
    Neighbor        V         AS   MsgRcvd   MsgSent   TblVer  InQ OutQ  Up/Down State/PfxRcd   PfxSnt
    10.0.2.3        4      64500       387       389        0    0    0 00:32:02 NoNeg
    10.0.2.4        4      64500         0         0        0    0    0    never       Active        0
    
    Total number of neighbors 2
    1 Confirm that the output includes a line for each BGP peer custom resource that you added.
    2 Output that shows 0 messages received and messages sent indicates a BGP peer that does not have a BGP session. Check network connectivity and the BGP configuration of the BGP peer.
  4. Display the BGP peers that received an address pool:

    $ oc exec -n metallb-system speaker-66bth -c frr -- vtysh -c "show bgp ipv4 unicast 203.0.113.200/30"

    Replace ipv4 with ipv6 to display the BGP peers that received an IPv6 address pool. Replace 203.0.113.200/30 with an IPv4 or IPv6 IP address range from an address pool.

    Example output
    BGP routing table entry for 203.0.113.200/30
    Paths: (1 available, best #1, table default)
      Advertised to non peer-group peers:
      10.0.2.3  (1)
      Local
        0.0.0.0 from 0.0.0.0 (10.0.1.2)
          Origin IGP, metric 0, weight 32768, valid, sourced, local, best (First path received)
          Last update: Mon Jan 10 19:49:07 2022
    1 Confirm that the output includes an IP address for a BGP peer.

Troubleshooting BFD issues

The Bidirectional Forwarding Detection (BFD) implementation that Red Hat supports uses FRRouting (FRR) in a container in the speaker pods. The BFD implementation relies on BFD peers also being configured as BGP peers with an established BGP session. As a cluster administrator, if you need to troubleshoot BFD configuration issues, you need to run commands in the FRR container.

Prerequisites
  • You have access to the cluster as a user with the cluster-admin role.

  • You have installed the OpenShift CLI (oc).

Procedure
  1. Display the names of the speaker pods:

    $ oc get -n metallb-system pods -l component=speaker
    Example output
    NAME            READY   STATUS    RESTARTS   AGE
    speaker-66bth   4/4     Running   0          26m
    speaker-gvfnf   4/4     Running   0          26m
    ...
  2. Display the BFD peers:

    $ oc exec -n metallb-system speaker-66bth -c frr -- vtysh -c "show bfd peers brief"
    Example output
    Session count: 2
    SessionId  LocalAddress              PeerAddress              Status
    =========  ============              ===========              ======
    3909139637 10.0.1.2                  10.0.2.3                 up  (1)
    1 Confirm that the PeerAddress column includes each BFD peer. If the output does not list a BFD peer IP address that you expected the output to include, troubleshoot BGP connectivity with the peer. If the status field indicates down, check for connectivity on the links and equipment between the node and the peer. You can determine the node name for the speaker pod with a command like oc get pods -n metallb-system speaker-66bth -o jsonpath='{.spec.nodeName}'.

MetalLB metrics for BGP and BFD

OpenShift Container Platform captures the following Prometheus metrics for MetalLB that relate to BGP peers and BFD profiles.

Table 2. MetalLB BFD metrics
Name Description

metallb_bfd_control_packet_input

Counts the number of BFD control packets received from each BFD peer.

metallb_bfd_control_packet_output

Counts the number of BFD control packets sent to each BFD peer.

metallb_bfd_echo_packet_input

Counts the number of BFD echo packets received from each BFD peer.

metallb_bfd_echo_packet_output

Counts the number of BFD echo packets sent to each BFD.

metallb_bfd_session_down_events

Counts the number of times the BFD session with a peer entered the down state.

metallb_bfd_session_up

Indicates the connection state with a BFD peer. 1 indicates the session is up and 0 indicates the session is down.

metallb_bfd_session_up_events

Counts the number of times the BFD session with a peer entered the up state.

metallb_bfd_zebra_notifications

Counts the number of BFD Zebra notifications for each BFD peer.

Table 3. MetalLB BGP metrics
Name Description

metallb_bgp_announced_prefixes_total

Counts the number of load balancer IP address prefixes that are advertised to BGP peers. The terms prefix and aggregated route have the same meaning.

metallb_bgp_session_up

Indicates the connection state with a BGP peer. 1 indicates the session is up and 0 indicates the session is down.

metallb_bgp_updates_total

Counts the number of BGP update messages sent to each BGP peer.

metallb_bgp_opens_sent

Counts the number of BGP open messages sent to each BGP peer.

metallb_bgp_opens_received

Counts the number of BGP open messages received from each BGP peer.

metallb_bgp_notifications_sent

Counts the number of BGP notification messages sent to each BGP peer.

metallb_bgp_updates_total_received

Counts the number of BGP update messages received from each BGP peer.

metallb_bgp_keepalives_sent

Counts the number of BGP keepalive messages sent to each BGP peer.

metallb_bgp_keepalives_received

Counts the number of BGP keepalive messages received from each BGP peer.

metallb_bgp_route_refresh_sent

Counts the number of BGP route refresh messages sent to each BGP peer.

metallb_bgp_total_sent

Counts the number of total BGP messages sent to each BGP peer.

metallb_bgp_total_received

Counts the number of total BGP messages received from each BGP peer.

Additional resources

About collecting MetalLB data

You can use the oc adm must-gather CLI command to collect information about your cluster, your MetalLB configuration, and the MetalLB Operator. The following features and objects are associated with MetalLB and the MetalLB Operator:

  • The namespace and child objects that the MetalLB Operator is deployed in

  • All MetalLB Operator custom resource definitions (CRDs)

The oc adm must-gather CLI command collects the following information from FRRouting (FRR) that Red Hat uses to implement BGP and BFD:

  • /etc/frr/frr.conf

  • /etc/frr/frr.log

  • /etc/frr/daemons configuration file

  • /etc/frr/vtysh.conf

The log and configuration files in the preceding list are collected from the frr container in each speaker pod.

In addition to the log and configuration files, the oc adm must-gather CLI command collects the output from the following vtysh commands:

  • show running-config

  • show bgp ipv4

  • show bgp ipv6

  • show bgp neighbor

  • show bfd peer

No additional configuration is required when you run the oc adm must-gather CLI command.

Additional resources