By default, APM server sends all its output to syslog. When you run APM server in the foreground, you can use the -e command line flag to redirect the output to standard error instead. For example:

apm-server -e

The default configuration file is apm-server.yml (the location of the file varies by platform). You can use a different configuration file by specifying the -c flag. For example:

apm-server -e -c myapm-serverconfig.yml

You can increase the verbosity of debug messages by enabling one or more debug selectors. For example, to view publisher-related messages, start APM server with the publisher selector:

apm-server -e -d "publisher"

If you want all the debugging output (fair warning, it’s quite a lot), you can use *, like this:

apm-server -e -d "*"