How to Use SCDB

Table of Contents

1. Getting Started
2. Template Compilation
3. Checking Compilation Results

Getting Started

To start with SCDB, you first need to install a ​Subversion server, an open source product. There are in fact 2 versions of Subversion server :

• http based : it is provided as an Apache module. This is the recommended version for production but is a litte bit more complex to setup than standalone version.
• standalone version : this should be used for testing, as it has less features than http based version.

There is no problem to start with standalone server and migrate to http server later (just the repository URL will change and it will require a new checkout) : repository are the same whatever the access method is.

After you have a Subversion server installed, you need to :

• Create a repository and import the basic SCDB structure from SCDB.
• Import QWG templates in cfg directory, according to the version you need. See QWG download instructions.

Template Compilation

All the template processing needed to build machine profiles is done with ant tools, a Java based equivalent of make. ant brings the advantage of platform independance, allowing to do Quattor management tasks on any platform (Unix, Windows, MacOS).

Specific management tasks (called targets) are passed as a parameter to ant command, in much the same way this is done with make. There are 3 main targets for managing Quattor (other targets are used internally by ant) :

• compile.all : this task recompiles all the machine profiles affected by template changes. This is the default if no target is specified.
• deploy : this task deploys the new machine profiles on the Quattor server. This can occurs only after successful compilation of all clusters.
• update.rep.templates : this task updates templates describing RPM repositories contents by scanning each repository associated directory.

Checking Compilation Results

When doing changes in configuration, this is often useful to check the resulting profiles before deploying. There is a small tool to help doing that, src/utils/profiles/compare_xml. This tool is part of SCDB base.

To use this tool, before compiling your changes, you need to copy your current (or reference) build directory to something else, by example build.saved (default name used by the script). After the compilation, if you run the script without arguments, it will display the list of all profiles that have changed. You can inspect the changes (require a bit of knowledge of profile contents) using option -v. Or you can restrict the check to one specific profile with option -p. By example :

# src/utils/profiles/compare_xml

Comparing XML files (*.xml)...
Differences found in build/xml/profile_grid05.xml
Differences found in build/xml/profile_grid06.xml
Differences found in build/xml/profile_grid07.xml

# src/utils/profiles/compare_xml -v -p profile_grid05

Comparing XML files (profile_grid05.xml)...
Differences found in build/xml/profile_grid05.xml
--- build.saved/xml/profile_grid05.xml  2006-07-28 11:41:45.000000000 +0200
+++ build/xml/profile_grid05.xml        2006-07-28 11:50:58.000000000 +0200
@@ -960,7 +960,6 @@
         <options>
           <dpm>
             <db>
-              <adminpwd type="string">MyPrefPwd</adminpwd>
               <adminuser type="string">root</adminuser>
               <configfile type="string">/opt/lcg/etc/DPMCONFIG</configfile>
               <password type="string">DpmMgrPwd</password>