Software repository replication using the ASIS Local Copy Manager

IT/DIS/OSE, CERN

ASIS TeamPresented by: German Cancio

(German.Cancio@cern.ch)

Presentation PlanPresentation Plan

Introduction to ASIS ASIS structure Transactional model Repository replication using ASISlcm Project status

Software Distribution: Goals and Software Distribution: Goals and RequirementsRequirements

Centralized management of SW applications necessary for: standard and homogeneous user environment better support (less diversity!)

Equally accessible by all supported platforms same availability same configuration

User nodes to see ‘ready to use SW’ trough a distributed file system

Software Distribution at CERN: Software Distribution at CERN: ASISASIS

ASIS: stands for Application Software Installation Service, offering: A multiplatform and multiversion SW repository with ready-to-use

applications A toolsuite for

assisted application compilation and configuration accessing, manipulating and replicating the repository

Contents: > 700 packages for ~8 platforms GNU software (compilers, system tools, editors, desktops) LaTeX X11 and contributions CERN program library Others, like Perl, Tcl/Tk, Java, licensed software

Platforms currently supportedPlatforms currently supported

ASIS (AFS) name Platform

i386_redhat51 RedHat Linux 5.1

sun4x_56 Sun Solaris 2.6

hp_ux102 HP_UX 10.20 ACE3

alpha_dux40 Digital UNIX 4.0b

rs_aix41 IBM AIX 4.1.5

rs_aix43 IBM AIX 4.3.2

sgi_64 SGI IRIX 6.5

Software Distribution at CERN: Software Distribution at CERN: ASIS (II)ASIS (II)

Main tools:

ASIShappi: concurrent software compilation and configuration on multiple platforms

ASISwsm: client workstation access to the repository

ASIStm: checks and validates repository modification requests

ASISlcm: repository update and replication ASIStar: generate tarfiles from ASIS packages

Logical organizationLogical organization

Packages are classified into Families, Products and Versions A family groups together products with similar origin or

functionality (i.e. MAIL, KDE, GNU.EDIT,CERN.LIB) A product may contain one or several versions (emacs-19.34,

emacs-20.2)

Each version is usually available for all supported platforms

‘share’ platform: contains common files (documentation, fonts, scripts)

Logical organization (II)Logical organization (II)

A model has been defined for the software processing from the sources release until delivery to users. Based on a state-transition diagram, 2 phases: generation and

deployment

A deployed package may be on one of the following states: In Production: default version, formally supported Certified: proved to work in the proper environment Under Certification: for evaluation by beta users

ASIS stores InProduction packages in a common area for improved efficiency

Client access to the repositoryClient access to the repository

ASISwsm manages the links from the repository to the workstation (in /usr/local or /cern)

The workstation administrator can customize the access to the packages (i.e. default version, specific, ignore)

Packages can be stored as ‘local copies’

ASIS

ASISwsm

ASISwsm

ASISwsm

ASISwsmASISwsm

ASIS repository

Transaction ModelTransaction Model

In order to group together related repository

modifications, a transactional system is used

A transaction is a sequence of operations... … either

a modification of the state of a package a ‘patch’ operation (modifying a package)

The atomicity of the execution of the transaction is guaranteed.

Transaction: exampleTransaction: example

Description: update emacs & related packages

RemoveFromProduction GNU.EDIT/emacs-19.34 (sun4x_55,alpha_osf32,hp_ux102)

RemoveFromProduction GNU.EDIT/vm-5.96beta (share)

IntroduceInProduction GNU.EDIT/emacs-20.2 (sun4x_55,alpha_osf32,hp_ux102,alpha_dux40)

IntroduceInProduction GNU.EDIT/vm-6.32 (share)

Transaction SystemTransaction System

Based on the cooperation between ASIStm (ASIS

transaction manager) and ASISlcm (ASIS local copy

manager)

A transaction is submitted to ASIStm, which checks its validity and coherence. The transaction is queued if accepted.

Repository modifications are carried out by ASISlcm

ASISlcm: Repository ReplicationASISlcm: Repository Replication

ASISlcm ... Reads transactions which are new since last run Determines what has to be done according to local

configuration Performs locally all selected transactions.

Only new packages are copied

ASISlcm can be run asynchronously, (i.e. at nighttime)

ASISlcm (II)ASISlcm (II)

Fault tolerance: ASISlcm rolls back the currently executed transaction in case of failure (i.e. when network problems arise) Transaction atomicity is always guaranteed.

Star scheme: modifications are propagated to the replicas (master/slave)

ASISlcm runs locally on the replicated site and only accesses the master when necessary

Replication costs proportional to the size of changes

Replication: example Replication: example

ASISASISlcm

CERN AFS master repository

ASIS

ASIS

ASIS

ASISlcm

ASISlcm

ASIStm

CERN NFS replica

Replica 1 on site XXX

Replica 2 on site XXX

WAN file system (AFS)LAN file system (NFS)

LAN file system (NFS)

Full repository replicationFull repository replication

ASISlcm also offers a ‘full’ replication mode State of all packages is checked against the master and updated

accordingly

When to use one mode or the other? Transactional (or incremental) replication:

frequent repository updates, i.e local replicas for load balancing

Full replication: initial repository cloning independent replicas (occasional updates) recovery after crashes

the full replication does not offer atomic properties

ASISlcm: configurationASISlcm: configuration

ASISlcm can be configured to match your site’s needs:

Filtering by architecture list of platforms to be replicated

Filtering by family / product: take all product versions skip a family / product / version ‘freeze’ a family / product / version based on the product’s state (Certified, In Production, Under

Certification)

ASISlcm: configuration exampleASISlcm: configuration example

Architectures:

sun4c_411 sun4x_55 hp700_ux90 hp_ux102 rs_aix41 alpha_osf32 sgi_52 i386_linux2

Products:

<All>/<All> InProduction # Lightweight copy

GNU.LANG/<All> None GNU.LANG/cvs InProduction GNU.LANG/rcs All

GNU.MISC/<All> Frozen GNU.MISC/gzip InProduction

MISC/<All> None MISC/a2ps InProduction MISC/tcsh 6.06 # Specific version nr MISC/arc Frozen

How to set up an ASIS local How to set up an ASIS local copy?copy?

1st. Get the ASIS software by mirroring from the CERN AFS tree or by downloading it from our ftp server

2nd. Configure and run ASISlcm (full) on your server(s)

3rd. Configure and run ASISwsm on your workstations

4th. Decide frequency and update type (full, incremental)

Please contact us for assistance!

ASIS project statusASIS project status

ASIS runs at CERN as part of the standard setup:

> 2000 nodes, > 10000 Users ~ 700 packages on ~ 20 GB

ASISlcm: in production for the CERN NFS server for 18 months on other sites: ???

EPFL (Swiss Federal Institute of Technology, Lausanne): acts as co-developer and owns a private repository

Further documentation and Further documentation and contactscontacts

ASIS has an URL on the web:

http://wwwinfo.cern.ch/dis/asis

with links to:

Guides (not up to date…) Product Documentation Site Usage Statistics Download area

Contacts:

ASIS team at CERN: asis.support@cern.ch