Log4j 2.17.2 added the needed building blocks via LOG4J2-3341 at the request of
the Hadoop and HBase projects.
For example, the out of the box HBase log4j2.properties file includes several
references to system properties, including this for the root logger:
```
rootLogger = ${sys:hbase.root.logger:-INFO,console}
```
And then our out of the box bootstrapping scripts include setting the parameter
based on an environment variable:
```
HBASE_OPTS="$HBASE_OPTS -Dhbase.root.logger=${HBASE_ROOT_LOGGER:-INFO,console}"
```
We could implement something similar to allow setting a system property to
change the root logger.
> On Jun 13, 2022, at 4:33 PM, Tristan Stevens <tris...@apache.org> wrote:
>
> Hi Ralph,
> That's the one that I had trouble with. Is there an equivalent system
> parameter that you can set to get the same behaviour with log4j2?
>
> Tristan
>
> Get Outlook for Android<https://aka.ms/AAb9ysg>
>
> ________________________________
> From: Ralph Goers <ralph.go...@dslextreme.com>
> Sent: Monday, 13 June 2022, 22:04
> To: dev@flume.apache.org <dev@flume.apache.org>
> Subject: Log4j & user doc
>
> Tristan,
>
> Although I see references to -Dflume.root.logger I see no place that actually
> implements support for it. So I removed those from the documentation.
>
> There are still references to Log4j 1 but those are all for Flume’s Log4j
> Appender, which still targets Log4j 1.
>
> Please review the Flume web site for any other issues there.
>
> Ralph
>
