It does resolve the initial problem. But then when I continue with the 2nd stage installation, it asks the IP config info again and doesn't let continue with the previously set config! So I had to set the gw to the same range of additional IP with subnet 24 to move on, then in the middle, installation failed 
Encountered an internal error. see /var/log/firstboot/vlcm_firstboot.py_11633_stderr.log
cat /var/log/firstboot/vlcm_firstboot.py_11633_stderr.log
Traceback (most recent call last):
File "/usr/lib/vmware-vlcm/firstboot/vlcm_firstboot.py", line 167, in <module>
main()
File "/usr/lib/vmware-vlcm/firstboot/vlcm_firstboot.py", line 129, in main
fb = VlcmFirstboot(VLCM_COMP, VLCM_SOLUSERNAME)
File "/usr/lib/vmware-vlcm/firstboot/vlcm_firstboot.py", line 50, in __init__
os.path.join(get_install_parameter('upgrade.import.directory'), "vlcm")
File "/usr/lib/vmware/site-packages/cis/tools.py", line 88, in get_install_parameter
raise InstallParameterException('Install-parameter %s not set' % param)
cis.exceptions.InstallParameterException: {
"detail": [
{
"id": "install.ciscommon.internal.error",
"translatable": "Encountered an internal error.\n\n%(0)s",
"args": [
"Install-parameter upgrade.import.directory not set"
],
"localized": "Encountered an internal error.\n\nInstall-parameter upgrade.import.directory not set"
}
],
"componentKey": null,
"problemId": null,
"resolution": {
"id": "install.default.failure.resolution",
"translatable": "This is an unrecoverable error, please retry install. If you encounter this error again, please search for these symptoms in the VMware Knowledge Base for any known issues and possible resolutions. If none can be found, collect a support bundle and open a support request.",
"localized": "This is an unrecoverable error, please retry install. If you encounter this error again, please search for these symptoms in the VMware Knowledge Base for any known issues and possible resolutions. If none can be found, collect a support bundle and open a support request."
}
