add external documentation links

howto/ganeti.md

@@ -1596,6 +1596,8 @@ There is no issue tracker specifically for this project, [File][] or
  [File]: https://gitlab.torproject.org/tpo/tpa/team/-/issues/new
  [search]: https://gitlab.torproject.org/tpo/tpa/team/-/issues
 
+Ganeti has of course its own [issue tracker on GitHub](https://github.com/ganeti/ganeti/issues).
+
 ## Monitoring and testing
 
 <!-- TODO: describe how this service is monitored and how it can be tested -->
@@ -1606,6 +1608,20 @@ There is no issue tracker specifically for this project, [File][] or
 <!-- TODO: where are the logs? how long are they kept? any PII? -->
 <!-- what about performance metrics? same questions -->
 
+## Other documentation
+
+ * [Ganeti](http://www.ganeti.org/)
+   * [Ganeti documentation home](http://docs.ganeti.org/)
+   * [Main manual](http://docs.ganeti.org/ganeti/master/html/)
+   * [Manual pages](http://docs.ganeti.org/ganeti/master/man/)
+   * [Wiki](https://github.com/ganeti/ganeti/wiki)
+   * [Issues](https://github.com/ganeti/ganeti/issues)
+   * [Google group](https://groups.google.com/forum/#!forum/ganeti)
+ * [Wikimedia foundation documentation](https://wikitech.wikimedia.org/wiki/Ganeti)
+ * [Riseup documentation](https://we.riseup.net/riseup+tech/ganeti)
+ * [DSA](https://dsa.debian.org/howto/install-ganeti/)
+ * [OSUOSL wiki](https://wiki.osuosl.org/ganeti/)
+
 # Discussion
 
 ## Overview