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The names and group section
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### The names and group section

#### Defining and using groups

Big Sister uses groups at various places. You will meet them when defining what systems' status will appear on which web page (see The Web pages section) as well as when setting up your alarming rules (see Configure alarmin).

In the system names and groups section of `bb-display.cfg` you specify displayed system and group names and define the group hierarchy. The most important statement you will want to remember is the Groups statement. All the lines between a Group statement and the next valid statement will be treated as group and/or name specifications.

Each line is of the form

    hostname(Displayed Host Name) GROUP1 ... GROUPN

or

    groupname(Displayed Group Name) GROUP1 ... GROUPN

where hostname/groupname is the name of a host (group resp.) and the string in parenthesis is the description of the host or group shown on web pages. GROUP1 through GROUPN are names of groups hostname/groupname is a member of.

Groups are created when they are first referenced so you can use an arbitrary name for both the groupname or GROUPN arguments. Groups may themselves be mem- bers of other groups.

| Warning
It is a good idea to avoid circular groups.

Time for an example: Assuming washington, paris and london are three systems monitored by Big Sister

    %Groups
    washington(Our server in Washington) USA SERVER
    paris(Our server in Paris) EUROPE SERVER
    london(Our server in London) EUROPE SERVER
    EUROPE(Good old Europe) WORLD
    USA(The United States) WORLD
    WORLD(all the continents) UNIVERSE
    SERVER(all our servers) UNIVERSE

the grouping statement above will create :

- a group called USA containing only the system washington,

- the group EUROPE containing the systems paris and london,

- the group WORLD containing the groups EUROPE and USA,

- the group SERVER containing all three systems,

- and finally the group UNIVERSE containing the groups SERVER and WORLD (see figure **).

Figure 3.2. Group hierarchy example

#### Automatically joined groups

Big Sister can automatically add a host to special groups at the time the first status message for the host comes in. Via the Autojoin statement you declare which groups Big Sister will use for this purpose. Basically there are three available autojoin features:

-     %Autojoin new GROUPNAME

  hosts joining in that are not member of any group yet (semantics: "they are new" / "not defined yet") will join the group named GROUPNAME. This is especially useful for detecting hosts which are already monitored by an agent but which are not correctly configured on server side.

- `%Autojoin all_hosts GROUPNAME`

  any host (but not groups!) becomes member of the group named GROUPNAME.

-     %Autojoin all GROUPNAME

  any host or group becomes member of the group named GROUPNAME.

#### Deleting groups

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