Provisioning Fedora CoreOS on VMware

This guide shows how to provision new Fedora CoreOS (FCOS) nodes on the VMware hypervisor.

Prerequisites

Before provisioning a FCOS machine, you must have an Ignition configuration file containing your customizations. If you do not have one, see Producing an Ignition File.

You also need to have access to a working VMware infrastructure, supporting VMs with at least hardware version 13. The examples below use the govc command-line tool.

Downloading the OVA

Fedora CoreOS is designed to be updated automatically, with different schedules per stream. Once you have picked the relevant stream, you can download the latest OVA:

STREAM="stable"
mkdir ova-templates
coreos-installer download -s "${STREAM}" -p vmware -f ova -C ./ova-templates/

Alternatively, OVA images can be manually downloaded from the download page.

Encoding Ignition configuration

For the vmware provider, Ignition requires two "guestinfo" fields to be present when the VM is first booted:

  • guestinfo.ignition.config.data.encoding: the encoding of the Ignition configuration.

  • guestinfo.ignition.config.data: the content of the Ignition configuration, encoded according to the format above.

For maximum compatibility, it is recommended to use base64 encoding and to prepare the Ignition configuration as such:

CONFIG_B64=`cat example.ign | base64 -w0 -`

Booting a new VM on vSphere

This section shows how to use vSphere facilities to configure and run VMs from the command-line. Similar steps can be performed via the graphical UI too.

Importing the OVA

The downloaded OVA has to be first imported into vSphere library:

FCOS_OVA='./ova-templates/fedora-coreos-31.20200210.3.0-vmware.x86_64.ova'
LIBRARY='fcos-images'
TEMPLATE_NAME='fcos-31.20200210.3.0'
govc session.login -u 'user:password@host'
govc library.create "${LIBRARY}"
govc library.import -n "${TEMPLATE_NAME}" "${LIBRARY}" "${FCOS_OVA}"

Setting up a new VM

You can now deploy a new VM, starting from the template in the library and the encoded Ignition configuration:

VM_NAME='fcos-node01'
govc library.deploy "${LIBRARY}/${TEMPLATE_NAME}" "${VM_NAME}"
govc vm.change -vm "${VM_NAME}" -e "guestinfo.ignition.config.data.encoding=base64"
govc vm.change -vm "${VM_NAME}" -e "guestinfo.ignition.config.data=${CONFIG_B64}"

A new fcos-node01 VM is now available for booting. Its hardware configuration can be further customized at this point, and then powered-up:

govc vm.info -e "${VM_NAME}"
govc vm.power -on "${VM_NAME}"

First-boot networking and Ignition

Ignition supports referencing remote content in configuration and fetching it at provisioning time. For this reason, on first-boot FCOS instances try to perform network autoconfiguration via DHCP.

If your VMware setup employs static network configuration instead, you can override this automatic DHCP setup with your own custom configuration. Custom networking command-line ip= parameter can be configured via guestinfo properties as shown below, before booting a VM for the first time.

The provisioning flow follows the usual steps, plus an additional guestinfo.afterburn.initrd.network-kargs entry.

if you are using a provisioning method other than govc, make sure that the guestinfo attribute is provisioned in the VM’s Advanced Configuration Parameters (also known as ExtraConfig). Some management tools may default to a vApp Property instead, which does not work in this scenario. 
VM_NAME='fcos-node02'
IFACE='ens192'
IPCFG="ip=192.0.2.42::192.0.2.1:255.255.255.0:${VM_NAME}:${IFACE}:off"

govc library.deploy "${LIBRARY}/${TEMPLATE_NAME}" "${VM_NAME}"
govc vm.change -vm "${VM_NAME}" -e "guestinfo.ignition.config.data.encoding=base64"
govc vm.change -vm "${VM_NAME}" -e "guestinfo.ignition.config.data=${CONFIG_B64}"
govc vm.change -vm "${VM_NAME}" -e "guestinfo.afterburn.initrd.network-kargs=${IPCFG}"
govc vm.info -e "${VM_NAME}"
govc vm.power -on "${VM_NAME}"

The full syntax of the ip= parameter is documented in Dracut manpages.

For further information on first-boot networking, see Afterburn documentation.