EDG LCFGng: concepts

1
EDG LCFGng concepts

• German.Cancio_at_cern.ch

2
LCFG (Local ConFiGuration system)

• LCFG is originally developed by the Computer
  Science Department of Edinburgh University
• Handles automated installation, configuration and
  management of machines
• Basic features
• automatic installation of O.S.
• installation/upgrade/removal of all (rpm-based)
  software packages
• centralized configuration and management of
  machines
• extendible to configure and manage EDG middleware
  and custom application software

3
LCFG system architecture
A collection of components read configuration
parameters and generate traditional service
config files, and notify/restart affected
services
Abstract configuration parameters for all nodes
stored in a central repository
4
LCFG system architecture
A collection of agents read configuration
parameters and either generate traditional config
files or directly manipulate various services
Abstract configuration parameters for all nodes
stored in a central repository
5
LCFG system architecture
A collection of agents read configuration
parameters and either generate traditional config
files or directly manipulate various services
Abstract configuration parameters for all nodes
stored in a central repository
6
LCFG system architecture
A collection of agents read configuration
parameters and either generate traditional config
files or directly manipulate various services
Abstract configuration parameters for all nodes
stored in a central repository
7
LCFG configuration changes

• Server-side after modifying the config files, a
  tool (mkxprof) is run which recreates the new xml
  profile for all the nodes affected by the changes
• mkxprof notifies via UDP the nodes affected by
  the changes
• Client-side another tool (rdxprof) downloads the
  new profile from the server
• usually activated by an LCFG component at boot

8
LCFG whats a component?

• Component object
• It's a Perl script (also shell scripts accepted
  for historic reasons)
• Each component provides a Configure() method
  invoked on startup or when configuration changes
• A simple and typical component behaviour
• Started when notified of a configuration change
  (new XML profile)
• Configures the appropriate services, by
  translating config parameters into a traditional
  config file and
• .. notifies a service if necessary (e.g.
  restarting a init.d service).

9
LCFG Software Package Management

• LCFG also manages the RPM packages to be
  installed on the client nodes.
• The software to install is defined in a file on
  the server containing a list of RPM packages
• The required RPM packages are installed/upgraded/r
  emoved by the LCFG package manager (updaterpms)
• started automatically at boot and via cron.
• Can be started by hand.

10
Updaterpms and local packages

• By default, updaterpms will remove all RPMs
  which are not declared in the configuration file
  of the node.
• Be careful when using updaterpms if you have
  added packages by hand
• The EDG version of updaterpms can be configured
  to allow locally installed packages (disabled by
  default)

11
LCFGng Server Installation

• The LCFGng server holds the following services
• Network installations (Diskette, PXE)
• Software repository (RPMs)
• Configuration Database
• This requires to run
• DHCP server for network boot information
• NFS server for accessing RPMs and installroot
  image
• HTTP server delivers XML node configurations
• The LCFGng server has to run Linux RedHat 6.2.
  Currently, RH62 and RH73 clients can be installed
  and managed from it.
• The LCFGng installation guide tells you in detail
  how to install the server.
• The LCFGng server is the only node not managed by
  LCFG itself.