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Quick start

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Get an Account

To get started using PDC resources within the Scania collaboration, please begin by apply for an account. In the electronic application, specify that you want to use the system Beskow. Also note that you are a part of the Scania collaboration at PDC as a comment. Once we have received your application we will confirm that you indeed are a Scania user, then, we will send you your account details.

Login

Once you have received your PDC account letter you may login at PDC. To connect to PDC from within Scania you first need to contact Scania IT to have your computer activated for PDC access. Then, you have to make sure that you follow the login instructions for your particular operating system.

Beskow

When accessing Beskow, use the Scania reserved login node:

 beskow-scania.pdc.kth.se

Login commands

The procedure to login to the PDC system from Scania first generate the Kerberos ticket according to:

 kinit -l 30d yourUsername@NADA.KTH.SE

One you have a valid ticket you can ssh to beskow-scania.pdc.kth.se using:

 ssh -K userid@beskow-scania.pdc.kth.se

File transfer

Files are transferred with scp from PDC to Scania as follows:

 scp yourUsername@beskow-scania.pdc.kth.se:filename .

Storage

Scania has its own dedicated Lustre disk system. It is available both Beskow:

/cfs/scania/

Especially, every user has the space:

/cfs/scania/home/u/userName

where u is the first letter of your userName. You should always run your programs in the parallel file system (Lustre).

File permissions

In Linux systems all files have a user, a group and a set of privileges which determines what resources a user can access. Every file has three different kind of access read('r'), write('w') and execute('x') as well as three different kind of permissions depending on if the person is the owner('u'=user) of the file, in the same group('g') and someone else('o'=other).

The command 'ls -l' is used to list the permission of the files in a directory,  for example,

lama-tst@emil-login2:~> cd testdir/
lama-tst@emil-login2:~/testdir> ls -l
total 4
drwxr-xr-x 2 lama-tst users 4096 2012-08-14 17:38 dir1
-rw-r--r-- 1 lama-tst users    0 2012-08-14 17:38 foo

The directory dir1, owned by user lama-tst, has the permissions drwxr-xr-x. The first character is used to indicate that the file is a directory(d), link(l) or an ordinary file(-). Then follows the permission (three positions each) for user, group and others.

The file foo is owned by the user lama-tst, the group permission is set for the group: users to -rw-r--r-- which means that lama-tst can read and write to the file, the user in the group users can read the file and so can all other users.

chmod

The command chmod can be used to change the permissions of a file.

lama-tst@emil-login2:~/testdir> chmod g+w foo
lama-tst@emil-login2:~/testdir> ls -l
total 4
drwxr-xr-x 2 lama-tst users 4096 2012-08-14 17:38 dir1
-rw-rw-r-- 1 lama-tst users    0 2012-08-14 17:38 foo

Add(+) write(w) permissions for group(g) to the file foo.

There is another way to set the permissions, namely using numbers. Assume that each permission equals the number listed below:

0 = no permissions
1 = execute
2 = write
4 = read

If you add the numbers of the permissions you would like to set you'll get a unique number, for example the only combination that adds up to 6 is read and write permission. so the command

lama-tst@emil-login2:~/testdir> chmod 753 foo
lama-tst@emil-login2:~/testdir> ls -l foo
-rw-rw-r-- 1 lama-tst users    0 2012-08-14 17:38 foo

gives the user the read, write and execute permission(4+2+1), the users in the same group gets read and execute permissions (4+1) and others get write and execute permissions (2+1).

ACLs

The command getfacl is used to get file access control lists (ACLs)

lama-tst@emil-login2:~/testdir> getfacl dir1
# file: dir1
# owner: lama-tst
# group: users
user::rwx
group::r-x
other::r-x

Note: Use option -c to skip the comment header. Here again, the directory dir1 is owned by the user lama-tst with permissions read('r'), write('w') and execute('x').  The permissions of group users are set to r-x which means that group users can read and execute and so can all other users.

The command setfacl is used to set the ACLs and with option -m to change the owner, groups and others of file

lama-tst@emil-login2:~/testdir> setfacl -m user:jon:rwx dir1
lama-tst@emil-login2:~/testdir> getfacl -c dir1
user::rwx
user:jon:rwx
group::r-x
mask::rwx
other::r-x
lama-tst@emil-login2:~/testdir> ls -dl dir1
drwxrwxr-x+ 2 lama-tst users 4096 2012-08-14 20:35 dir1

Now the user jon has been added and can access to dir1 with permission read('r'), write('w') and execute('x'). Note that there is an additional '+' character displayed after all permissions of dir1 that have extended ACLs.

Moreover, the options '-x' is used to remove entries from the ACLs of file and '-R' to recurse into subdirectories

lama-tst@emil-login2:~/testdir> setfacl -x user:jon dir1
lama-tst@emil-login2:~/testdir> getfacl -c dir1
user::rwx
group::r-x
mask::r-x
other::r-x

You can read more about ACLs here.

Software

Please take a look at this page to see which software is installed at PDC. Especially, you might be interested in:

Contact Support

If you have any problems or comments, PDC support is more then happy to help you! Please send us your question at:

scania-support@pdc.kth.se

We are using a support ticket system so you will receive an immediate response including your support ticket number:

[SNIC support #NNNNN]

You are encouraged to start several errands if you have many questions. Also, take care not to re-open old support errands by reusing old ticket numbers (happens if you take "reply to" on an old errand without changing the subject). You can read more about our RT system here.

Mailing list

 

Scania users are added to the mailig list:

 scania-users@pdc.kth.se

Both PDC staff and Scania users may post on this list and e-mails goes directly to all users. This list can be used to quickly spread information, for instance if some PDC system is unavailable we will post a message on this list.