HP XC System 2.x Software - Manual (Page 27)

2
Using the System
This chapter describes tasks and commands that the general user must know to use the system.
It contains the following topics:
• Logging in to the system (Section 2.1)
• Setting up the user environment (Section 2.2)
• Launching and managing jobs (Section 2.3)
• Performing some common user tasks (Section 2.4)
• Getting help (Section 2.5)
2.1 Logging in to the System
Logging in to an HP XC system is similar to logging in to any standard Linux system. Logins
are performed on nodes that have the login role. Secure Shell (ssh) is the preferred method
for accessing the HP XC system.
2.1.1 LVS Login Routing
The HP XC system uses the Linux Virtual Server (LVS) facility to present a set of login nodes
with a single cluster name. When you log in to the system, LVS automatically routes your login
request to an available login node on the system. LVS load balances login sessions across the
login nodes and improves the availability of login access. When you log in to the HP XC system,
you do not have to know specific node names to log in, only the HP XC system’s cluster name.
2.1.2 Using ssh to Log In
To log in to an HP XC system, you must use Secure Shell ( ssh ). Typically, you access the HP
XC system using the ssh command to get a login shell or to execute commands. For example:
$ ssh user-name@system-name
user-name@system-name’s password:
The ssh service also allows file transfer using the scp or sftp commands over the same
port as ssh .
The typical r* UNIX commands, such as rlogin , rsh , and rcp , are not installed on an HP
XC system by default because of their inherent insecurity. The ssh command transfers all login
and password information in an encrypted form instead of the plaintext form used by the r*
UNIX commands (as well as telnet and ftp ).
If you want to use ssh without password prompting, you must set up ssh authentication keys.
Refer to the ssh (1) manpage for information about using ssh authentication keys.
ssh is further discussed in Section 10.1.
2.2 Configuring Your Environment with Modulefiles
The HP XC system supports the use of Modules software to make it easier to configure and
modify the your environment. Modules software enables dynamic modification of your
environment by the use of modulefiles. A modulefile contains information to configure the
shell for an application. Typically, a modulefile contains instructions that alters or sets shell
Using the System 2-1