Recommended configuration
For a three-node Kubernetes cluster, each VM/host in the cluster should have a minimum of:

Ubuntu 20 LTS or higher

8 vcpus / 8 cores

28Gb memory

500Gb disk space

If
/var is a separate filesystem, it should have at least 150Gb of storage

If
/opt is a separate filesystem, it should have at least 150Gb of storage

Solid State Disk (SSD) is
strongly recommended

If spinning disk (HDD) is used, the rating should be
at least 10000rpm