Additional setup for RHCOS virtual machine on KVM hypervisor

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There are some special requirements if you want to provision a RHCOS virtual machine on KVM hypervisor.

Here are the details:

  1. As RHCOS virtual machine provision depends on DHCP service, if the compute node is configured with RoCE Express network, network administrator is needed to setup a DHCP server manually to control the IP address allocation to RHCOS virtual machines in this network.

  2. Use administrator's username and password to get the authority to run IBM® Cloud Infrastructure Center CLI according to Setting environment variables.

  3. The OVN network that is created through Adding a network needs to be a DHCP network. If not, the administrator needs to enable the DHCP for the subnet in the network. The commands are:

    openstack subnet list --network <network-name>

    openstack subnet set --dhcp <subnet-name-or-ID>

    Note: the network-name is the network name that you want to use to provision the RHCOS virtual machine, the subnet-name-or-ID is from the output of the previous command, is the subnet name or ID in the network.

  4. When use L3 network in the environment, DHCP also needs to be enabled when you deploy the RHCOS virtual machine.

  5. For KVM OVN multiple flat or vlan networks that are created through Add multiple KVM flat and Add multiple KVM vlan, they must all be DHCP network as well. For example, create a KVM flat subnet: openstack subnet create --allocation-pool start= <IP range start> ,end= <IP range end> --network <network-name> --dhcp --subnet-range <subnet-range IP> --gateway <gateway IP> <subnetwork-name>

  6. It is possible to specify an IP address to a virtual machine when using the DHCP network. You can specify the virtual machine's ip address in Image Deploy page.