You can find the shiny new documentation here, which is replacing over time this one.
Thus, this article is obsolete and may be not valid anymore - however, the new one is not finished yet!
1. General Information
Nagstamon is a Nagios status monitor used on desktops. It show up as tray icon in the system tray or as floating statusbar.
Nagstamon uses the classic Nagios CGIs to fetch the status information about Nagios hosts and services. This leads to a lot of load on the Nagios system when several clients are running Nagstamon at the same time.
To reduce the load on the Nagios system Multisite provides a new JSON based web service since version 1.1.9i8. This web service can be used by clients like Nagstamon to fetch Nagios status information using a fast and lightweight protocol.
To use the web service there is a server module included in Nagstamon since 0.9.5. It can connect directly to the Multisite web service to fetch status information from one or multiple sites.
The web service in multisite is implemented as regular view which can be shown with JSON output instead of regular HTML output. Mutlisite comes with two default views named nagstamon_hosts and nagstamon_svc which are used when connecting Nagstamon to Multisite.
2. Configuring Nagstamon
To connect Nagstamon to multisite right click on the Nagstamon icon, open the settings dialog and click on New server....
In the following dialog select Checkmk Multisite as server type, insert a server name of your choice. Then add the URL you use to open Multisite in your browser to as value for the server url parameter. For example if you use http://192.168.0.70/check_mk/ to access Multisite just put http://192.168.0.70/check_mk/ into the input field.
The server cgi url parameter is not used by the backend. You can leave the value at it's default value.
At last you need to enter a valid username of your choice and if you like to store the users password enter the password.
Now confirm the new server dialog and the settings dialog. On next update interval Nagstamon should connect to the new server.