node-exporter 9100 port is open on nodes which node-exporter pods are running at, for example:
# netstat -anlp | grep 9100
tcp6 0 0 :::9100 :::* LISTEN 54236/node_exporter
tcp6 0 0 172.16.120.88:9100 10.128.0.10:56394 ESTABLISHED 54236/node_exporter
and node-exporter target could be accessed without error
# openshift version
Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.
For information on the advisory, and where to find the updated
files, follow the link below.
If the solution does not work for you, open a new bug report.