Some OpenShift nodes show two different IP addresses on the same host network interface

Solution Verified - Updated -

Environment

  • Red Hat OpenShift Container Platform 4.x.

Issue

  • Some OpenShift nodes show two different IP addresses on the network interface that they use to communicate with the host network and therefore other nodes in the cluster.
# ip a show ens192
2: ens192: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq state UP group default qlen 1000
    link/ether D1:5F:07:5A:B1:6D brd ff:ff:ff:ff:ff:ff
    inet 10.154.56.81/24 brd 10.154.56.255 scope global dynamic noprefixroute ens192
       valid_lft 68375sec preferred_lft 68375sec
    inet 10.154.56.4/32 scope global ens192
       valid_lft forever preferred_lft forever
    inet6 fe80::107d:c22f:dac4:6e88/64 scope link noprefixroute 
       valid_lft forever preferred_lft forever
  • Is this expected or is it an anomalous behavior?

Resolution

  • This is an expected behavior if there is any egress IP configured in the cluster.
    • If there is a cluster where this is not the case and it is suspected that there may be something wrong, feel free to contact Red Hat Support to debug the potential issue.

Root Cause

  • As explained on our documentation, Red Hat OpenShift Container Platform implements the egress IP functionality by configuring these additional IP addresses in its nodes.

This solution is part of Red Hat’s fast-track publication program, providing a huge library of solutions that Red Hat engineers have created while supporting our customers. To give you the knowledge you need the instant it becomes available, these articles may be presented in a raw and unedited form.

Comments