This is just to document something that felt odd (aka FTR)
The installation of said service (done by prepare_vra_template.sh) includes a link of /opt/vmware-appdirector/agent-bootstrap/vmware_vra_software_agent to /etc/init.d. For some reason I could not find, RHEL7 and CentOS7 do not run scripts that are not real files (i.e. symlinks) during system initialization and as a result, the template install succeeds but the VMs fail to deploy the vra software agent.
The fix is available elsewhere, and documents how to edit the file to remove the import of "functions", which I don't think matters, and then to create a copy of the file instead of a link to /etc/init.d/vmware_vra_software_agent.
If you failed to do that, then any software deployment request will get stuck at "processing". This is AFAIK another interesting situation as there is no standar way to cancel or destroy the request in this state. You have to go into CLI mode and access the DB directly to get read of it.
For a VRA6 document discussing this, see VMware KB: Requests get stuck at In Progress or Pending Approval status in VMware vRealize Automation 6.x. For a VRA7 writeup see http://open902.com/vra7-delete-stuck-in-progress-deployments/ (external).