packages "bug"

[Brendan Strejcek]

cfengine locking can get in the way of package definitions. For example,
consider the following:

########################################################################

==> main.cf <==

    #!/usr/sbin/cfagent -qvf
    
    control:
        actionsequence = ( packages )
    
    import:
        /tmp/one.cf
        /tmp/two.cf

==> /tmp/one.cf <==

    packages:
        bash
            pkgmgr=rpm
            define=bash_pkg_installed
    
    alerts:
        bash_pkg_installed::
            "one.cf: bash_pkg_installed class defined"

==> /tmp/two.cf <==

    packages:
        bash
            pkgmgr=rpm
            define=bash_package_installed
    
    alerts:
        bash_package_installed::
            "two.cf: bash_package_installed class defined"

########################################################################

When I run that, this is what happens:

    Installable classes = ( bash_pkg_installed bash_package_installed )
    ...
    RPMCheckPackage(): Requested bash eq ANY
    cfengine:: Nothing scheduled for packages.packages (0/1 minutes elapsed)
    ...
    ---------------------------------------------------------------------
    Alerts
    ---------------------------------------------------------------------
    cfengine:: one.cf: bash_pkg_installed class defined

We can see that the second class is not getting defined due to a lock.
Why is this bad? It means that any admin that defines a class like
this needs to understand the entire site config, or actions predicated
on their class may never occur. I suspect other sections may exhibit
similar behavior, but I have not tested it yet.

Fundamentally, I think this is a problem of scope and namespaces. I
think that is one of the weakest elements of cfengine, so I hope it
is addressed in version 3. Namespaces are intimately connected with
reusability.

Best,
Brendan

--
Senior System Administrator
The University of Chicago
Department of Computer Science

http://www.cs.uchicago.edu/people/brendan

http://people.cs.uchicago.edu/~brendan