A. Yes, there are two ways to delete the abandoned machine agent, either from controller UI by creating a dummy application or through a manual step to delete the agent from the database. The steps for both are located here: Delete abandoned machine agent.
A. There are two solutions for this, found here: Agent Status on .NET
A. The message indicates that account key generated by AppDynamics controller during the registration may be changed at this point in time. This could happen if you migrate the Controller without shutting down the agents. Restart the agent to resolve this error.
A. Follow these steps to troubleshoot:
-XX:MaxPermSize=<value>) to a higher value (256m at least) and try again.
A. Reset agent before requesting the agent log.
A. We need to run one machine agent process for each application on a machine.
-Dappdynamics.agent.uniqueHostId=<<some unique value per application>>) to both Machine Agent and the App Agent. Provide the same value to the machine - app agent pair.
-Dappdynamics.agent.uniqueHostId=a1for n1 and m1. and
-Dappdynamics.agent.uniqueHostId=a2for n2 and m2.
A. It's not out of the box, but there is a workaround.