Final answer:
The interaction events between vCenter Server and ESXi 6.x host are logged in the vpxd.log file. This log is used by vCenter Server to track tasks, events, system failures, changes, and ESXi host statuses.
Step-by-step explanation:
The interactions between the vCenter Server and the ESXi 6.x host can be viewed in the vpxd.log file. This log shows the communication between the vCenter Server and its components. The vCenter Server uses it to track tasks and events performed within the environment, including actions performed by system users, system failures and changes, and ESXi host changes and statuses.
For instance, if an ESXi 6.x host loses its communication link with the vCenter Server, the vpxd.log file would show the event and provide detailed information about the condition and the date and time when it occurred.
Learn more about vpxd.log