HP XC System Software Administration Guide Version 3.2.1

The login service is assigned to any node in the LVS ring. LVS assigns a user login to one
of these nodes whenever that user requests a login to the system through the system name
or Internet Protocol (IP) address.
A login node requires a connection to the external network.
• I/O service
An I/O node provides I/O services for the system.
The I/O nodes provide access to Storage Area Networks (SANs) connected to the node,
access to file systems that are mounted locally to the node, or both.
An I/O node should reside in the utility cabinet and connect to the root Ethernet switch.
• Network Address Translation (NAT) Server
The NAT server node provides external access to the nodes in the system that do not have
an external network connection.
The system can have multiple NAT servers configured to balance the access to the external
network.
• Management Hub Services
The node that provides management hub services is a central point for management daemons,
including those that provide system logs and performance information.
• Load Sharing Facility for High Performance Computing (LSF-HPC with SLURM) master
server
LSF-HPC with SLURM is an implementation of the Load Sharing Facility (LSF) for HP XC
systems.
The node that is assigned this service is responsible for running the LSF-HPC with SLURM
daemons.
• Image server service
The golden client maintains an image of the file system that is the model for all the nodes
in the HP XC system. SystemImager is the underlying technology used to install the HP XC
software, distribute the golden image, and distribute configuration changes. With the
SystemImager, you can update every node with systemwide information, such as user
account data.
Note:
The golden client and SystemImager are bound to the same node.
• Configuration database server
The node assigned this service is the MySQL configuration database server for this system.
For additional information on the configuration database, see “Configuration and
Management Database” (page 39) .
• Dynamic Host Control Protocol (DHCP) server
This service assigns IP addresses for all devices on the internal network based on the DHCP
server node's Machine Access Control (MAC) address.
• Power daemon service
The power subsystem daemon enables you to turn on, turn off, cycle, and reset power on
individual nodes, and also report whether a node's power is on or off.
This daemon is automatically assigned to the head node.
For additional information on nodes and services, see the HP XC System Software Installation
Guide.
1.1 Understanding Nodes, Services, and Roles 29