Hello && Welcome @icsj2007
Ill be honest, I’m not good with Docker but I maybe able to help troubleshoot this issue with you.
This would help, what i found about GL Docker was from here
And this…
And I ran into this forum for Docker.
I believe if you can find your log4j2.xml ( Should be in your Graylog Directory) this should point where your log files are.
As for your Elasticsearch logs with Docker, I have found this. It may help later on.
Normally your Graylog log files would be located in /var/log/graylog-server