There are a few
‘gotchas’ with Variables which are noted below. If you have any issues with Variables, please refer first to this section.
Number of characters
A Variable’s value
field can only contain 63 characters or less. This is because Opsview
Monitor cannot allow the service description to be longer than 128 characters,
when combined with the Service Check name. If it is longer, this will fail a
reload and the message below will be displayed:
Service description '....' is greater than 128 characters. Please change
the attribute or Service Check name to be shorter.
restrictions on what characters can be placed within the ‘value’ field. The value
field can only consist of alphanumeric
characters, space, a period (”.”), a forward slash (”/”) or a dash (”-”), up to
63 characters; this is because the value could be used in the Service Check
name, which has restrictions on the characters used. Any trailing spaces will
be removed. Also, the argument field allows any characters, but be aware that
Nagios Core may process some special characters like !, $ and \. These special
characters must be ‘escaped’, for example ‘Password11!’ becomes ‘Password11\\!’,
and ‘PAS$WORD’ becomes ‘PAS$$WORD’.
This is the name of the Variable.
Names can only consist of the letters A-Z (upper case only) or an
underscore, up to 63 characters.
Internally generated variables
Some Variables are
internally-generated, so it is not necessary to manually add information at the Host edit pages. There are currently three internally-generated variables:
INTERFACE - based on the SNMP interfaces
stored from a query Host call
SLAVENODE - returns a list of all slave
CLUSTERNODE - returns a list of all other
cluster nodes within a slave environment
Note, however, that
you still need to associate the relevant Service Checks to the Host. In the
initial database, these templates can be used
Associating a Host to
the appropriate Host template will ensure the Service Checks get created