Last week, I was working happily in the vSphere fat client, and suddenly received the error, “The request failed because the server closed the connection. The underlying connection was closed: A connection that was expected to be kept alive was closed by the server.” What does this VMware actually mean?
Turns out that I was doing basic host maintenance tasks at the time. One of the commands I initiated was on a host that was already in maintenance mode, and which I wanted to reboot. Unbeknownst to me, the host was already being rebooted by a different administrator.
Note that had the other administrator issued a command via the vSphere fat client, or the web client, then VMware would have known the server was coming down. But, instead, they had logged into the CLI via SSH and issued the reboot command at the prompt.
So, in summary, it was just a matter of coordinating amongst us humans.