I suppose that the Datum is also the timestamp of the event.
In this case, please try something like this:
| rex "(?ms).*Description:\s(?<Description>.*).*Node:\s+(?<Node>.*).*Severity:\s+(?<Severity>.*)"
| table _time Description Node Severity
That you can test at https://regex101.com/r/tCns4x/1
If Datum isn't also the timestamp, you have two ways:
- modify your props.conf to use Datum as timestamp (_time),
- insert datum in the regex
I hint the first solution.