monitoring-plugin can not be started on IPv6 disabled cluster as the pod listen on [::]:9443. 

Monitoring-plugin should listen on [::]:9443 on IPv6 enabled cluster
Monitoring-plugin should listen on 0.0.0.0:9443 on IPv6 disabled cluster.


$oc logs monitoring-plugin-dc84478c-5rwmm2023/10/14 13:42:41 [emerg] 1#0: socket() [::]:9443 failed (97: Address family not supported by protocol)nginx: [emerg] socket() [::]:9443 failed (97: Address family not supported

4.14.0-rc.5

Always

cat <<EOF |oc create -f -
apiVersion: machineconfiguration.openshift.io
kind: MachineConfig
metadata:
  labels:
    machineconfiguration.openshift.io/role: master
  name: 99-openshift-machineconfig-master-kargs
spec:
  kernelArguments:
  - ipv6.disable=1
EOF
 
cat <<EOF |oc create -f -
apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
metadata:
  labels:
machineconfiguration.openshift.io/role: worker
  name: 99-openshift-machineconfig-worker-kargs
spec:
  kernelArguments:
   -  ipv6.disable=1
EOF

$ oc get mcp |grep worker.
worker   rendered-worker-ba1d1b8306f65bc5ff53b0c05a54143f   False     True       False      5              3                   3                     0                      3h59m

$oc logs machine-config-controller-5b96788c69-j9d7k
I1014 13:05:57.767217       1 drain_controller.go:350] Previous node drain found. Drain has been going on for 0.025260005567777778 hours
I1014 13:05:57.767228       1 drain_controller.go:173] node anlim14-c6jbb-worker-b-rgqq5.c.openshift-qe.internal: initiating drain
E1014 13:05:58.411241       1 drain_controller.go:144] WARNING: ignoring DaemonSet-managed ……
I1014 13:05:58.413116       1 drain_controller.go:144] evicting pod openshift-monitoring/monitoring-plugin-dc84478c-92xr4
E1014 13:05:58.422164       1 drain_controller.go:144] error when evicting pods/"monitoring-plugin-dc84478c-92xr4" -n "openshift-monitoring" (will retry after 5s): Cannot evict pod as it would violate the pod's disruption budget.
I1014 13:06:03.422338       1 drain_controller.go:144] evicting pod openshift-monitoring/monitoring-plugin-dc84478c-92xr4
E1014 13:06:03.433295       1 drain_controller.go:144] error when evicting pods/"monitoring-plugin-dc84478c-92xr4" -n "openshift-monitoring" (will retry after 5s): Cannot evict pod as it would violate the pod's disruption budget.

$oc extract cm/monitoring-plugin
$cat nginx.conf 
error_log /dev/stdout info;
events {}
http {
  include            /etc/nginx/mime.types;
  default_type       application/octet-stream;
  keepalive_timeout  65;
  server {
    listen              9443 ssl;
    listen              [::]:9443 ssl;
    ssl_certificate     /var/cert/tls.crt;
    ssl_certificate_key /var/cert/tls.key;
    root                /usr/share/nginx/html;
  }
}

Monitoring-plugin listens on [::]:9443 on IPv6 enabled cluster

Monitoring-plugin listens on 0.0.0.0:9443 on IPv6 disabled cluster.

The PR about how logging fix this issue. https://github.com/openshift/cluster-logging-operator/pull/2207/files#diff-dc6205a02c6c783e022ae0d4c726327bee4ef34cd1361541d1e3165ee7056b38R43