Adding global vars to mimic Icinga 1 resources

Icinga 2
1

Many of you are familiar with the good old $USERn$ macros from Icinga 1.x.

They were used for various purposes, but best known for storing credentials / passwords in a central place.

In Icinga 2 you can define “global” vars, that will be available to any object, by adding them to IcingaApplication

Example

An easy to maintain example can work like this:

constants.conf

// ... any other vars
const GlobalVars = {
  USER10 = "some-username"
  USER11 = "some-generic-password"
  local_mysql_user = "icinga"
  local_mysql_password = ""
}

conf.d/app.conf

object IcingaApplication "app" {
  // vars can also be defined inline here...
  vars = GlobalVars
}

conf.d/services.conf

apply Service "mysql" {
  import "generic-service"

  check_command = "mysql"

  vars = {
    mysql_username = "$local_mysql_user$"
    mysql_password = "$local_mysql_password$"
  }
}

Be careful

  • Those vars are enabled globally, and will work in every macro
  • If you use any variable name that is used by a CheckCommand, the value may be used unintentionally
  • Those variables are always last in order (after service, host, checkcommand)
  • Variables can be used by any user that is able to change config

Recommendations

  • Use a prefix or site specific variable name
  • Maintain the vars in constants.conf and only set the const to vars in IcingaApplication
  • Document available vars for other users

Any opinions or questions on this?

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