Morning Stefan,
In our instance, the user name is the unix account that starts the mq agent with the "./startMQMonitor.sh &". In our case, we have an account on a Suse Linux server called "wilymq" which owns the wilyMQ directory. We log into the server using our login account then sudo (su) into the wilymq user account. Then when we issue the startMQMonitor, the wilymq user is used to call to the MQ instance on a different host.
On the MQ, you would need to assign the agent user to the groups "mqm" for MQ queue manager group and then the mqbrkrs in order to query the IIB (broker) queues.
You should be able to issue the "groups" command from the command line (linux) while logged into the wilymq account and get back "wilymq mqm mqbrkrs" on both the agent host and the MQ host.
There is a section in the APM for IBM MQ with the title "Set the MCA User ID" which has:
"If you do not specify the MCA User ID at connect time, the server uses the client user ID.
By defining the MCA User ID in the channel definition you can override the privileges of the client user ID"
Now, I'm not an MQ admin so I can't tell you if these accounts are default groups or what permissions from the OS to MQ are assigned to these groups.
For Broker, there is a MBMonitorJMSQueues.mqsc file that will create the reporting queues. I found this down under the agent directory under properties.
Additional, you will need to copy the communication jars from your MQ instance to the agent and place them within the <agent home>/lib then align the start script. The list of jars are listed within the startMQMonitor.sh script at the top.
Hope this helps,
Billy