Latest butane binary is having some issues, it is not able to convert .bu to .yaml.

# butane 98-partition.bu -o 98-partition.yamlError translating config: No translator exists for variant openshift with version 4.14.0

rhcos 4.14.x

Download latest butane binary and try to convert the provided 98-partition.bu 

1. Download the latest butane binary 
"curl https://mirror.openshift.com/pub/openshift-v4/clients/butane/latest/butane --output butane"

2. Convert the file as below :

# cat 98-partition.bu
variant: openshift
version: 4.14.0
metadata:
  labels:
    machineconfiguration.openshift.io/role: worker
  name: 98-var-partition-worker
storage:
  disks:
  - device: /dev/disk/by-id/sda
    partitions:
    - label: var
      start_mib: 30000
      size_mib: 35000
  filesystems:
    - device: /dev/disk/by-partlabel/var
      path: /var
      format: xfs
      mount_options: [defaults, prjquota]
      with_mount_unit: true

# butane 98-partition.bu -o 98-partition.yaml
Error translating config: No translator exists for variant openshift with version 4.14.0 

3. As per below document, it should work.
"https://docs.openshift.com/container-platform/4.14/installing/install_config/installing-customizing.html#installation-special-config-butane-install_installing-customizing"

# butane 98-partition.bu -o 98-partition.yaml Error translating config: No translator exists for variant openshift with version 4.14.0 

It should be able to convert to .yaml file.

Below butane package is able to convert it.

"butane-0.19.0-1.1.rhaos4.14.el8.x86_64.rpm" from below url.
https://access.redhat.com/downloads/content/butane/0.19.0-1.1.rhaos4.14.el8/x86_64/fd431d51/package

And install it on rhel-8 (not RHCOS) server as below:
# rpm -Uvh butane-0.19.0-1.1.rhaos4.14.el8.x86_64.rpm

Then run the command :
# butane 98-partition.bu -o 98-partition.yaml