Using asadmin e.g. to get server variables require a username

[Király Péter]

In administering the service you should be able to use Payara's asadmin command line tool, but by default it fails:

$ docker container exec -ti dataverse /bin/bash
# /opt/payara/appserver/bin/asadmin list-jvm-options | grep dataverse
Authentication failed for user: null 

(Usually, this means invalid user name and/or password)

If one tries it from the host, asadmin asks for credentials:

$ docker container exec -ti dataverse /opt/payara/appserver/bin/asadmin list-jvm-options
Enter admin user name:

Solution: Add the admin user name ('admin') and password ('admin') to README

But pipeline still not works. To prevent to be asked again, you should do the following steps:

1. enter the container command line environment

$ docker container exec -ti dataverse /bin/bash

2. enter credentials ('admin' and 'admin')

# /opt/payara/appserver/bin/asadmin login
Enter admin user name [Enter to accept default]>
Enter admin password>
# exit

3. Test if it works:

$ docker container exec -ti dataverse /opt/payara/appserver/bin/asadmin list-jvm-options | grep dataverse