you could also wrap this entire section of resources in a conditional

```
if node['ntp']['sync_clock']
  execute "Stop #{node['ntp']['service']} in preparation for ntpdate" do
    ...
  end

  execute "Sync system clock with ntp server" do
    ...
  end

  unless platform_family?('windows')
    execute "Sync hardware clock with system clock" do
      ..
    end
  end
```