The node-exporter pods throws following errors if `symbolic_name` is not present or provided by fibre channel vendor.  

$ oc logs node-exporter-m6lbc -n openshift-monitoring -c node-exporter | tail -2
2023-09-27T12:13:39.403106561Z ts=2023-09-27T12:13:39.403Z caller=collector.go:169 level=error msg="collector failed" name=fibrechannel duration_seconds=0.000249813 err="error obtaining FibreChannel class info: failed to read file \"/host/sys/class/fc_host/host0/symbolic_name\": open /host/sys/class/fc_host/host0/symbolic_name: no such file or directory"

https://github.com/prometheus/node_exporter/blob/master/collector/fibrechannel_linux.go#L116C28-L116C28

The ibmvfc kernel module does not supply `symbolic_name`.

    https://github.com/torvalds/linux/blob/master/drivers/scsi/ibmvscsi/ibmvfc.c#L6308

1. grep -v "zZzZ" -H /sys/class/fc_host/host*/port_state
   /sys/class/fc_host/host0/port_state:Online
   /sys/class/fc_host/host1/port_state:Online

sh-5.1# cd  /sys/class/fc_host/host0
sh-5.1# ls -ltr
total 0
rrr-. 1 root root 65536 Sep 28 19:43 speed
rrr-. 1 root root 65536 Sep 28 19:43 port_type
rrr-. 1 root root 65536 Sep 28 19:43 port_state
rrr-. 1 root root 65536 Sep 28 19:43 port_name
rrr-. 1 root root 65536 Sep 28 19:43 port_id
rrr-. 1 root root 65536 Sep 28 19:43 node_name
rrr-. 1 root root 65536 Sep 28 19:43 fabric_name
rw-rr-. 1 root root 65536 Sep 28 19:43 dev_loss_tmo
rw-rr-. 1 root root 65536 Oct  3 09:24 uevent
rw-rr-. 1 root root 65536 Oct  3 09:24 tgtid_bind_type
rrr-. 1 root root 65536 Oct  3 09:24 supported_classes
lrwxrwxrwx. 1 root root     0 Oct  3 09:24 subsystem -> ../../../../../../class/fc_host
drwxr-xr-x. 2 root root     0 Oct  3 09:24 power
rrr-. 1 root root 65536 Oct  3 09:24 maxframe_size
-w------. 1 root root 65536 Oct  3 09:24 issue_lip
lrwxrwxrwx. 1 root root     0 Oct  3 09:24 device -> ../../../host0