You need to create agent and run it on all the nodes to read log files of node. In activity you need to put logic to grab log file of each node.
You can create DSS containing the log file location for each node. May be node ID as setting name and location as value.
Then in agent activity just determine the Node ID and read corresponding DSS and its value to read the file content. Not tried this approach so might need some correction as well but this could help you to achieve your goal.