Preventing DHCP from assigning an IP address on node reboot

Red Hat OpenShift Container Platform supports deploying an installer-provisioned cluster with static IP addresses on nodes from the baremetal network for environments without a DHCP server. If a DHCP server is present on the baremetal netowrk, to prevent a DHCP server from assigning an IP address in lieu of a static IP address, use this procedure.

Procedure

1. Before installation, create machineconfig manifests for both control plane nodes and worker nodes:

    apiVersion: machineconfiguration.openshift.io/v1
    kind: MachineConfig
    metadata:
      labels:
        machineconfiguration.openshift.io/role: <role> 
        name: 10-static-workaround-<role>
    spec:
      config:
        ignition:
          version: 3.2.0
        systemd:
          units:
          - contents: |
              [Unit]
              Description=Static IP Workaround
              Wants=NetworkManager-wait-online.service
              After=NetworkManager-wait-online.service
              Before=ovs-configuration.service
              [Service]
              Type=oneshot
              ExecStart=/bin/bash -c "for i in $(nmcli --fields NAME,UUID -t con show | grep 'Wired Connection' | awk -F : '{print $2}'); do nmcli con modify $i match.interface-name '!<interface_name>'; done"
              [Install]
              WantedBy=multi-user.target
           enabled: true
              name: static-workaround.service
   

   Replace <role> with the role of the node. This should be master or worker. Replace <interface_name> with the name of the network interface. For example, enp2s0.

2. Copy the manifests to the same directory as the generated manifests. They must be in the same directory as other manifests as detailed in Creating the OpenShift Container Platform manifests. Ensure that you create a manifest for each role.

3. Proceed with installation.