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2. Arla
   Arla is a freeware AFS project created by KTH Stacken. They also provide some documentation. Installing Arla demands that you have a working Kerberos (step 1 above).

* After downloading and unpacking the source, you need to configure the Makefile to use Kerberos 4 and then make the package:

> ./configure --with-krb4=/usr/athena --with-krb4-lib=/usr/athena/lib --with-krb4-include=/usr/athena/include
> make
> make install

* Arla should now be installed, but we're not ready yet! First we need to tell Arla what cell to use:

> echo rhic >/usr/arla/etc/ThisCell

* In your arla build directory there is a conf/ directory with a services file. Append this file to /etc/services:

> cp /etc/services /etc/services.no_arla
> cd [your arla build directory]/conf
> cat services >>/etc/services

* Check the rhic information in the cell servers database (/usr/arla/etc/CellServDB). Find the rhic entry and confirm that the afs servers are:

If your arla distribution is of later date than, say, summer of 2000, then the AFS servers are probably correct. Please contact me if these servers have changed.

* Create the soft link:

> ln -s /afs/rhic/@sys/opt/phenix /opt/phenix

where @sys will automatically point to the right kernel (see below).

* Add the line

   source /opt/phenix/bin/phenix_setup.csh

to your .login / .tcshrc or whatever you're using, or create an alias to it (it takes a while to source it if BNL is on the other side of the Earth..).

* Almost done! Add /usr/arla/bin to your PATH variable.

* You are now ready to start Arla! Give the command

> startarla

This will start the Arla daemon and mount the AFS tree on /afs. Before you start to use Arla, first set the AFS system name variable (sysname). Without it you will not be able to benefit from automatic system specific directory names. E.g. the directory 'arch/.@sys/' will be interpreted as 'arch/i386_redhat61/' on a Linux system with Red Hat 6.1 installed, if we set the sysname variable to the value i386_redhat61. (Note for PHENIX users: As of May 2000, setting sysname to i386_redhat62 will break the soft links since there are no such directories yet; i386_redhat61 works just fine.) Set it with the fs command:

> /usr/arla/bin/fs sysname i386_redhat61

* Test Arla with 'klog [your RCF user name]' and why not an 'ls /afs/rhic/phenix'? It can take several seconds to perform an ls command.

Tip: You may want to start Arla automatically every time your machine boots. Add the following lines to your /etc/rc.d/rc.local file:

   /usr/arla/bin/fs sysname i386_redhat61

and (more importanly) do a

> chkconfig --level 5 arla on

This will start and stop the Arla daemon automatically at run level 5. The default run level is set in /etc/inittab. Run level 5 starts X at boot. If you don't want to start Arla at a run level, you can start it in the rc.local file by hand, but don't forget to remove the cache (rm -rf /usr/arla/cache) first.

Another tip: You can check the status of the Arla daemon by issuing a '/etc/rc.d/init.d/arla status'. With a '/etc/rc.d/init.d/arla stop' you stop it. A '/etc/rc.d/init.d/arla start' starts it again.

Yet another tip: It might be a good idea to install and run a Network Time Protocol (ntp) daemon to keep your local machine synchronized with the AFS servers, since an AFS client can't be unsynchronized to the server with more than 5 minutes. xntpd should accompany your Red Hat distribution. If it's not already installed, it can be found in the RPMS directory of the Red Hat CD-ROM (e.g. xntp3-5.93-15.rpm) or from Red Hat homepage. A source distribution can be downloaded from The Time Synchronization Server home page.

* Before you start the xntpd daemon, comment all commands in the installed /etc/ntp.conf file and add the following NTP servers:


xntpd will automatically choose the best server.

* Start it with:

> /usr/sbin/xntpd

* It takes a while before it has synchronized your machine. You can check the progress by sending queries to the daemon:

> /usr/sbin/ntpq
ntpq> peers

     remote           refid      st t when poll reach   delay   offset    disp
*     3 u  527 1024  377   146.29   -4.730    1.74     3 u  550 1024  377   146.56   -1.651    1.74     3 u  628 1024  377   144.62   -8.291    1.46

At the time of the snapshot, rnis00 was chosen for synchroniztion (*). All times are in seconds.

If your system clock should be off (the time synchronization will be set automatically), you can set it by using a local ntp server, e.g. (NTP server in Lund):

> date
Tue May 16 12:15:20 CEST 2000
> rdate -s
> date
Tue May 16 12:13:00 CEST 2000
> /usr/sbin/setclock (set the hardware clock)

Should you encounter problems with klog authentication although you're sure that you have an AFS user id, it might very well be related to time synchronization. Solution? Start xntpd and wait until your machine is synchronized with the AFS server, then try klog again. Do not underestimate the power of the xntpd daemon!

Pål Nilsson, June 2000.


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