how does kubernetes change the disk pressure of a node?

Resolved. It turned out I used wrong syntax to configure thresholds. Here is correct way to set those:

evictionSoft:
  memory.available: "100Mi"
  nodefs.available: "100Mi"
  nodefs.inodesFree: "1%"
  imagefs.available: "100Mi"
  imagefs.inodesFree: "1%"
evictionSoftGracePeriod:
  memory.available: 5m
  nodefs.available: 5m
  nodefs.inodesFree: 5m
  imagefs.available: 5m
  imagefs.inodesFree: 5m
evictionHard:
  memory.available: "100Mi"
  nodefs.available: "100Mi"
  nodefs.inodesFree: "1%"
  imagefs.available: "100Mi"
  imagefs.inodesFree: "1%"

(config file is located at /var/lib/kubelet/config.yaml in my case)

Then kubelet needs to be restarted: sudo systemctl restart kubelet

And here is a useful command to get kubelet logs to check if it started correctly: journalctl -u kubelet --since "1min ago"