Over the weekend, I was looking at a way to install the VMware vCenter Server Appliance 6.0 update 1 from command line. The process is straightforward. We generate a template (JSON) file with all required parameters and give it to vcsa-deploy.exe in the .\vcsa-cli-installer\win32 folder of the mounted or extracted ISO.
For me the real problem was when I started using vcsa-deploy.exe. It started throwing errors just after the JSON validation and while logging into the ESX host specified in the JSON template.
2015-10-04 17:59:44,875 - vCSACliInstallLogger - ERROR - An error occurred when connecting to "ESX-1": Failed to login to host ESX-1, as user root: [Errno socket error] [Errno 8] _ssl.c:499: EOF occurred in violation of protocol
2015-10-04 17:59:44,875 - vCSACliInstallLogger - DEBUG - The vCenter Server Appliance installer log file is at: c:\users\admini~1\appdata\local\temp\2\vcsaCliInstaller-2015-10-04-12-29-wgyrvy\vcsa-cli-installer.log
2015-10-04 17:59:44,875 - vCSACliInstallLogger - DEBUG - The vCenter Server Appliance installer result file is at: c:\users\admini~1\appdata\local\temp\2\vcsaCliInstaller-2015-10-04-12-29-wgyrvy\vcsa-cli-installer.json
I spent sometime looking around for help and tried things like enabling SSH on the ESX host and so on. When nothing solved the issue, I looked at the network trace and realized that vcsa-deploy.exe was trying to use the proxy configured on the local host. Sigh!
So, the solution to this was either disabling proxy settings in Internet Explorer or adding the ESX host FQDN to the bypass list under proxy configuration.