TestWNClient0711

Testing of OSG WN Client in ITB 1.1.33 (07/2011).

Background

This version of worker-node client includes updated LFC bindings for both 32 and 64 bit versions of python 2.4, 2.5, and 2.6. Python 2.6 is required by the latest dq2 client. As of 7/29/2011 this package is available in both the "lfc-test" cache (a "pre-release" cache from VDT) and the ITB cache. At this point we recommend using the ITB cache.

Requirements:

1. RHEL 5 based OS (SL5 or Centos5)
2. Update ATLAS-OSG-compat package (see below)
3. python 2.6

If you are replacing OSG WN Client and ATLAS-wn in a single worker node on a cluster with installations in shared directories, then the use of bind mounts to override the content of a directory may come handy.

Install OSG WN Client

You can follow the instructions in the OSG Worker Node Client Install guide. Replace the cache (http://software.grid.iu.edu/osg-1.2) with ITB each time it appears in a Pacman command, e.g.:

[root@wn /opt/wn-client]$ pacman -get ITB:wn-client

Remember to setup the CA certificates following the usual OSG instructions.

Install the ATLAS workernode (ATLAS-wn) package

This package is necessary because:

• It provides the DQ2Clients (latest release in the version used here)
• It sets environment variables
• It fixes a compatibility issue with the ATLAS releases

Generic instructions to install ATLAS-wn are here. You will need to install the ATLAS-wn-rolling version (the production version points to DQ2Clients 0.1.35), i.e.

pacman -get http://www.mwt2.org/caches/:ATLAS-wn-rolling

IMPORTANT! Before issuing the Pacman command above you have to have OSG wn-client already installed and the environment variable OSG_GRID must contain the root installation directory (e.g. export OSG_GRID=/opt/wn-client, if don't have it in your environment).

IMPORTANT 2! DQ2Clients 0.1.36 (latest release included in ATLAS-wn-rolling as of 7/29) and following do require python 2.5 or greater. The system python in RHEL 5 based systems is 2.4.

Install python 2.6

The default python from SL5 is python 2.4 whereas dq2 requires 2.5 or greater. We suggest python 2.6 (and not 2.5 or 2.7) because it is available from EPEL. Here we present 2 alternatives:

• Install python 2.6 from EPEL (preferred)
• Install python 2.6 using Pacman

Install python 2.6 from EPEL

You need to be root. Add the EPEL repository. Note that this will alter your system yum repositories!

rpm -Uvh http://download.fedoraproject.org/pub/epel/5/i386/epel-release-5-4.noarch.rpm

Install python26:

yum install python26

Change the DQ2Clients package to use python26. All dq2 scripts start with /usr/bin/env python but the system python in the path is still 2.4. To change them to use python26 do the equivalent of:

cd /osg/app/atlas_app/atlaswn/DQ2Clients/opt/dq2/bin/
for i in * ; do sed -i "1s|#!/usr/bin/env python|#!/usr/bin/python26|" $i; done

Install python 2.6 with Pacman

Choose the correct package:

• Python32bit26 if you have a 32 bit OS (can work also on 64 bit OS if you need it for a test)
• Python64bit26 if you have a 64 bit OS and prefer 64 bit python (recommended for 64 bit OS)

Go in the same directory where you installed ATLAS-wn and install it, e.g.:

pacman -get http://www.mwt2.org/caches/:Python64bit26

This will add python 2.6 as default python once the setup file is sourced (so the sed operation described above is not required).

-- MarcoMambelli - 29 Jul 2011