Namespaced Quattor configuration

Work In Progress

Setup

The current Quattor 1.3 setup is entirely different from the Quattor 1.2 setup. It is therefore located in a different tree in CVS: nl.nikhef.ndpf.quattor-config/conf-ns/. This tree contains the templates and the infrastructure needed to maintain, build and deploy templates. Various tools assume that there is an evironment variable $L that points to the location where the contents of this tree in CVS are present.

The build and deploy infrastructure is derived from SCDB: [1]

The major difference to standard SCDB is that our setup is independent of SubVersion, whereas SCDB relies on the presence of a SubVersion repository. The setup is still built around an ant build script build.xml, which governs various tasks.

Building and deploying templates is easiest with the shell scripts makexprof and pushxprof, respectively. Note that the latter is a symlink to the former. Syntax:

makexprof -f <facility-name> [template1] [template2] [...]
pushxprof -f <facility-name> [template1] [template2] [...]

The option -f with argument <facility-name> is required to select one of the facility names. Currently defined facilities: itb (Installation Test Bed), prd (Production cluster) and generic (miscellaneous Quattor-managed servers).

Updating the templates that describe the contents of the package repositories is done by directly executing the task update.rep.templates in the Ant script:

( cd $L ; ant update.rep.templates )

To generate update templates (i.e., templates that replace older version of software), the tool $L/../bin/rpmUpdates.pl can be used:

rpmUpdates.pl /path/to/update/rpm/directory  > updates.tpl

creates an update template (prepared for namespace rpms/updates) based on the contents of /path/to/update/rpm/directory.

Templates

Current setup uses namespaces (see below).

Description of namespace hierarchy.

Namespaces

Quattor release 1.3 uses the concept of namespaces for organizing templates. The name of template in a namespace corresponds to its parent directory (or directories) that contain it with respect to the include root. An example: assume the include root for the Pan compiler is $I, then a template with path $I/my/namespaced/template.tpl should have the name my/namespaced/template in Pan:

template my/namespaced/template;

# contents

Combining namespaced templates with the Pan feature called loadpath gives tremendous flexibility in defining various template tree parallel to each other with the possibility to select from a template which of the trees to use for compilation. The loadpath is set by built-in Pan variable LOADPATH, which is a list strings to consider to resolve a requested template.

A concrete example is the selection of the operating system. Assume the file system hierarchy under the include root $I is as follows:

$I
   +- centos3_i386
      +- some
         +- template
   +- centos4_i386
      +- some
         +- template

Then it is possible to

include some/template;

from other templates if either centos3_i386 or centos4_i386 was added to the Pan variable LOADPATH.