Static IP addresses on bare-metal servers for OKD4.x

[alrf]

Is there an official way to configure a static IP address on an:
a) existing bare-metal node in a cluster?
b) new bare-metal node in a cluster?

What was attempted unsuccessfully:

1. NMState operator - doesn't work because the NIC is managed by OVN/OVS. NMState cannot assign IPs to interfaces controlled by OVN/OVS, so applying static IPs on these nodes always results in FailedToConfigure:

[2026-02-04T11:24:17Z INFO  nmstate::ifaces::inter_ifaces] Ignoring interface ovn-k8s-mp0 type ovs-interface
[2026-02-04T11:24:17Z INFO  nmstate::ifaces::inter_ifaces] Ignoring interface 0127c5b0e39d39b type ethernet
[2026-02-04T11:24:17Z INFO  nmstate::ifaces::inter_ifaces] Ignoring interface 50642e8164c688f type ethernet
[2026-02-04T11:24:17Z INFO  nmstate::ifaces::inter_ifaces] Ignoring interface b9bbd6745cc0a09 type ethernet
[2026-02-04T11:24:17Z INFO  nmstate::ifaces::inter_ifaces] Ignoring interface genev_sys_6081 type ethernet
NmstateError: InvalidArgument: Interface enp0s31f6 cannot have IP enabled as it is attached to a controller where IP is not allowed:
failed to execute nmstatectl apply --no-commit --timeout 480: exit status 1 
LastHeartbeatTime:2026-02-04 11:24:17.353620922 +0000 UTC m=+70040.249587601 
LastTransitionTime:2026-02-04 11:24:17.353620922 +0000 UTC m=+70040.249587601} 
{Type:Available Status:False Reason:FailedToConfigure Message: LastHeartbeatTime:2026-02-04 11:24:17.353621125 +0000 UTC m=+70040.249587803 LastTransitionTime:2026-02-04 11:24:17.353621125 +0000 UTC m=+70040.249587803}



# nmcli connection show
NAME                UUID                                  TYPE           DEVICE
ovs-if-br-ex        a0356562-ebb7-4147-adeb-6d6be11181ce  ovs-interface  br-ex
br-ex               94d7fc7f-b1a7-4855-ab42-d9d87f0ad097  ovs-bridge     br-ex
ovs-if-phys0        69d98a89-c432-47ea-a580-c12c4119ade4  ethernet       enp0s31f6
ovs-port-br-ex      b32b1993-320d-4903-8bcc-348d1c65e41a  ovs-port       br-ex
ovs-port-phys0      af6e72d5-7773-4294-b099-de074981a07b  ovs-port       enp0s31f6
lo                  11aa90a0-fda3-4163-bcca-e25979a79149  loopback       lo
Wired connection 1  c28ff3d3-5f1b-3e43-ac39-658115e462d1  ethernet       --

2. nmcli - manual changes are temporary. Each node is controlled by the Machine Config Operator (MCO), if you change network settings manually, MCO sees that as an error and resets it during reboot or reconciliation.

@JaimeMagiera please help

[forzamehlano]

For new nodes absolutely yes.

How do you build your nodes? You can assign static addresses when building via PXE, or by ISO (https://docs.okd.io/4.17/nodes/nodes/nodes-nodes-adding-node-iso.html#:~:text=You%20can%20add%20worker%20nodes,how%20you%20installed%20your%20cluster.) by specifying the relevant nmstate config at build time.

[alrf]

Solved.
The commands below are used for static network configuration and ensuring network connectivity on CoreOS (OKD4), both on an existing system and during a fresh installation.

Assign static IP on an existing server in OKD4 cluster, reboot is required:

rpm-ostree kargs --append="ip=<IP>::<GATEWAY>:<NETMASK>:<HOSTNAME>:<INTERFACE>:<OPTIONS>"
reboot

Assign static IP when installing a server from scratch:

coreos-installer install -i <FILE>.ign -f coreos-raw.xz --insecure /dev/nvme0n1 --append-karg="ip=<IP>::<GATEWAY>:<NETMASK>:<HOSTNAME>:<INTERFACE>:<OPTIONS>" --append-karg="nameserver=<DNS_IP>"

The nameserver parameter is mandatory; otherwise, the server cannot connect to api-int.

[nate-duke]

how does this factor in with systems provisioned with a cloud-init datasource available?

We've found that our systems (IPI) provisioned with a cloud-init NoCloud datasource (iso9660 in our case) will maintain their cloud-init provided configuration following the pivot from FCOS to SCOS (and beyond?).