Ubuntu worker nodes are now natively available on Oracle Kubernetes Engine (OKE), with Console, CLI and Terraform support, without any need for custom images. Please see my recent blog here:
https://ubuntu.com/blog/ubuntu-worker-nodes-for-oracle-oke-now-in-limited-availability
With this developers can now enjoy a consistent Ubuntu experience across worker nodes on the managed Kubernetes offerings of Amazon AWS, Google Cloud Platform, IBM Cloud, Microsoft Azure and Oracle OCI.
Please give it a try and let us know how you get on!