Containment
Containment in Puppet means that included classes are not contained in the same way as resources in a class; so, when setting up a dependency to a class that includes another class via the include function or a class resource, the dependency will only cover the resources. For example, say we created a requirement for class1 to be applied before class2 and class2 contained a package resource and an include call to class3, as shown in the following code:
include examplemodule::class1, examplemodule::class2
Class['examplemodule::class1'] -> Class['examplemodule::class2']
class examplemodule::class2 {
include examplemodule::class3
package{'PDS':}
}
So, while there might be an assumption that this would ensure class1 was before class3 but class1 was before class2, it doesn’t, as can be seen in the DAG diagram in Figure 6.3.
Figure 6.3 – DAG showing lack of containment
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