i have seen many times questions about this, so here is a way to upload your own templates or iso in cloudstack.
this may not be the best solution, but this is the way I uploaded my own templates/isos and it works! any suggestion is very welcome!

• I m using 2 machines:
  -management server = 192.168.146.211
  -host = 192.168.146.212
• in my host i have created a directory : /var/www/repo/img
• in this "img" directory, i put all my qcow2, vmdk, iso files, or whatever you need
• it is important to correctly add the extensions to each files, for example a qcow2 must be named "myFile.qcow2"
• I cd in this img directory, and enter "python -m SimpleHTTPServer 443" => This exposes the contents of my "img" directory on the port 443, as a simple http server (as the command lets it guess!)
• now, I can access this content on my web browser:  _http://192.168.146.212:443_
• since it is a local repo, i have to fill in the global settings of CloudStack: "secstorage.allowed.internal.sites" to value "192.168.146.0/24" (since this is my CIDR here)
• I now just have to go to the template tab, select "create template" or "create iso" according to my need
• as URL I enter: _http://192.168.146.212:443/myFile.qcow2_ and fill in the other fields correctly, validate and it should download!

• if you need to restart the download of a template:
  ssh into your SSVM, and enter "service cloud stop", then "service cloud start". This seems to work better thant "service cloud restart", that do not work every time on my machine with CS3.0.1 (the service seems to try to restart before it is actually really stopped)

Hope this can help someone!