uncloud/doc/README-how-to-configure-remote-uncloud-clients.org

* What is a remote uncloud client?
** Systems that configure themselves for the use with uncloud
** Examples are VMHosts, VPN Servers, cdist control server, etc.
* Which access do these clients need?
** They need read / write access to the database
* Possible methods
** Overview
|                          | pros                                                      | cons                                 |
| SSL based                | Once setup, can access all django parts natively, locally | X.509 infrastructure                 |
| SSH -L tunnel            | All nodes can use [::1]:5432                              | SSH setup can be fragile             |
| ssh djangohost manage.py | All DB ops locally                                        | Code is only executed on django host |
| https + token            | Rest alike / consistent access                            | Code is only executed on django host |
| from_django              | Everything is on the django host                          | main host can become bottleneck      |
** remote vs. local Django code execution
   - If manage.py is executed locally (= on the client), it can
     check/modify local configs
   - However local execution requires a pyvenv + packages + db access
   - Local execution also *could* make use of postgresql notify for
     triggering actions (which is quite neat)
   - Remote execution (= on the primary django host) can acess the db
     via unix socket
   - However remote execution cannot check local state
** from_django
   - might reuse existing methods like celery
   - reduces the amount of things to be installed on the client to
     almost zero
   - follows the opennebula model
   - has a single point of failurebin