SURVIVOR: host.cf
About host.cf
syntax
  • Whitespace is generally ignored, unless otherwise noted.
  • boldface denotes keywords.
  • [brackets] denote optional keywords.
  • Separators (|) denote mutually exclusive keywords.
  • Comments begin with a # symbol, and may appear anywhere. Comments must be terminated with newlines. 
     <name> : [a-zA-Z0-9\.+%@_-]+

host.cf defines HostClasses, which are distinct sets of hosts with common basic characteristics, Groups, which are sets of hosts that are monitored for a given Check, and Group Aliases, which duplicate a Group under another name.

A preparsing utility is available to verify host.cf before installation.

HostClasses
syntax 
     class <name> {
         hosts {
	     <name>
	     [...]
	 }
	 [check on <name> schedule]
	 [alert on <name> alertplan]
     }

About HostClasses

A class stanza defines the default check and alert characteristics of its member hosts. Any host monitored by the scheduler must be defined in exactly one HostClass.

Dependencies

  • The Schedule specified by the check keyword in a hostclass definition must be defined in schedule.cf.
  • The Alert Plan specified by the alert keyword in a hostclass definition must be defined in schedule.cf.

HostClass Stanza Keywords

class <name> Define a new HostClass, which defines the default Check Schedule and Alert Plan for its hosts. The HostClass all is reserved.
hosts <name> Define the set of hosts in the HostClass. A host must be a member of exactly one HostClass in order to be monitored.
check on <name> schedule Define the default Check Schedule for the members of the HostClass. Individual Checks can override this default.
alert on <name> alertplan Define the default Alert Plan for the members of the HostClass. Individual Checks can override this default.

Examples

  1. In the following example, server1 and server2 will by default have all of their Checks run on the critical Schedule and alert notifications will be transmitted according to the critical Alert Plan. 
         class servers {
       hosts {
         server1
         server2
       }

       check on critical schedule
       alert on critical alertplan
     }

Groups
syntax 
     group <name> {
	 <name>
	 [...]
     }

About Groups

A Group is a set of zero or more hosts. A host may be a member of zero or more Groups. If a host is specified in a Group but not defined in a HostClass, it may be silently ignored.

Group names are used to select which Checks are executed for which hosts. A Check is executed on a host when the following conditions are met:

  1. A host is a member of a Group.
  2. There is a corresponding Check defined in check.cf with the same name as that Group.
  3. The host is defined in a HostClass.

Dependencies

  • The hosts specified in a Group definition must be defined by a Host Class definition before the Group definition that references them.

Group Stanza Keywords

group <name> Define a new Group. The Group name all is reserved.

Examples

  1. In the following example, if a Check named http is defined, it will be run for hosts server1 and server2. 
         group http {
       server1
       server2
     }

Group Aliases
syntax 
     alias <name> to <name>

About Group Aliases

A Group Alias is simply another name for the identified set of hosts. This is useful in order to have multiple Checks run on the same set of hosts without having to maintain multiple identical Groups.

Dependencies

  • The original Group specified in a Group Alias definition must be defined before the Alias definition that references it.

Group Alias Stanza Keywords

alias <name> to <name> Define a new Group Alias. The name by to is the name of the "new" Group.

Examples

  1. In the following example, the imap Group is aliased to pop and smtp so that imap, pop, and smtp may be checked on the same set of hosts. 
         alias imap to pop
     alias imap to smtp

  2. The following is equivalent to the first example: 
        alias imap to smtp
    alias smtp to pop

Next: check.cf

$Date: 2006/11/19 14:16:53 $
$Revision: 0.3 $
 keywords
alert on alertplan
alias
check on schedule
class
group
hosts