Network UPS Tools User Manual

Network UPS Tools User Manual 7 / 84
2.12.1 Access Restrictions
The CGI programs use hosts.conf to see if they are allowed to talk to a host. This keeps malicious visitors from creating queries
from your web server to random hosts on the Internet.
If you get error messages that say "Access to that host is not authorized", you’re probably missing an entry in your hosts.conf.
2.12.2 upsstats
upsstats generates web pages from HTML templates, and plugs in status information in the right places. It looks like a distant
relative of APC’s old Powerchute interface. You can use it to monitor several systems or just focus on one.
It also can generate IMG references to upsimage.
2.12.3 upsimage
This is usually called by upsstats via IMG SRC tags to draw either the utility or outgoing voltage, battery charge percent, or load
percent.
2.12.4 upsset
upsset provides several useful administration functions through a web interface. You can use upsset to kick off instant
commands on your UPS hardware like running a battery test. You can also use it to change variables in your UPS that accept
user-specified values.
Essentially, upsset provides the functions of upsrw and upscmd, but with a happy pointy-clicky interface.
upsset will not run until you convince it that you have secured your system. You must secure your CGI path so that random
interlopers can’t run this program remotely. See the upsset.conf file. Once you have secured the directory, you can enable
this program in that configuration file. It is not active by default.
2.13 Version Numbering
The version numbers work like this: if the middle number is odd, it’s a development tree, otherwise it is the stable tree.
The past stable trees were 1.0, 1.2, 1.4, 2.0, 2.2 and 2.4, with the latest stable tree designated 2.6. The development trees were
1.1, 1.3, 1.5, 2.1 and 2.3. As of the 2.4 release, there is no real development branch anymore since the code is available through
a revision control system (namely Subversion) and snapshots.
Major release jumps are mostly due to large changes to the features list. There have also been a number of architectural changes
which may not be noticeable to most users, but which can impact developers.
2.14 Backwards and Forwards Compatibility
The old network code spans a range from about 0.41.1 when TCP support was introduced up to the recent 1.4 series. It used
variable names like STATUS, UTILITY, and LOADPCT. Many of these names go back to the earliest prototypes of this software
from 1997. At that point there was no way to know that so many drivers would come along and introduce so many new variables
and commands. The resulting mess grew out of control over the years.
During the 1.3 development cycle, all variables and instant commands were renamed to fit into a tree-like structure. There are
major groups, like input, output and battery. Members of those groups have been arranged to make sense - input.voltage and
output.voltage compliment each other. The old names were UTILITY and OUTVOLT. The benefits in this change are obvious.
The 1.4 clients can talk to either type of server, and can handle either naming scheme. 1.4 servers have a compatibility mode
where they can answer queries for both names, even though the drivers are internally using the new format.
When 1.4 clients talk to 1.4 or 2.0 (or more recent) servers, they will use the new names.
Here’s a table to make it easier to visualize: