A service is a process that monitors a specific
condition but is usually otherwise inactive. When the condition changes,
the service activates itself to perform a given function. In addition
to the Linux services, there are HP XC system services, which
are described in this chapter, and Nagios services. Chapter 8 contains information
on Nagios.
The service command is the primary
means for stopping and restarting services on the HP XC system.
The syntaxes of the service command
are as follows:
service [servicename [subcommand ]]
In the [servicename [subcommand]] syntax statement, the available subcommands depend on
the individual servicename. Consider the
following example, in which the user invokes the service
snmpd command, then invokes the service nagios command. In each instance, a usage note is returned.
# service snmpd
Usage: /etc/init.d/snmpd
{start|stop|status|restart|condrestart|reload}
# service nagios
Usage: nagios {[n]start|[n]stop|[n]restart|reload|status|condrestart}
{|[un]nconfigure|[un]gconfigure} |
The options for each service differ. The snmpd and nagios services both have
the start, stop, status, restart, and reload subcommands
in common, but other subcommands are unique to the individual service.
Usually, the start, stop, restart, and status subcommands are available for all services.
Table 4-1 lists key Linux system services and key services
from third-party sources. These services are listed alphabetically
by their database name.
Table 4-1 Linux and third-party System Services
| Service | Function | Database Name |
|---|
| Database Server | Runs the management database server. | dbserver |
| DHCP Server | Assigns IP addresses to nodes. | dhcp |
| Myrinet Switch Monitor | Monitors the Myrinet switch. | gmmon |
| Hardware Information Gathering | Gathers information about hardware for
the management database. | gather_data |
| Apache Web Server | Web server used by Nagios. | httpd |
| IP Firewall | Sets up IP firewalls on nodes. | iptables |
| LSF Master Node | Load Sharing Facility for HP XC master
node. | lsf |
| LVS Director | Handles
the placement of user login sessions on nodes when a user logs in
to the cluster alias. | lvs |
| NAT Server | Network Address Translation server. | nat |
| NAT Client | Network Address Translation client. | nat_client |
| Network Adapter Setup | Gathers information about all network adapters
and stores it in the management database. | network |
| NFS Server | Runs an NFS server for sharing file systems. | nfs_server |
| Network Time Protocol | Synchronizes the clocks of nodes. | ntp |
| Syslog | System logging
service. | syslog |
| Syslog-ng Aggregator | Gathers logging information from subordinate
nodes running syslog. | syslogng_forward |
| Quadrics Switch Monitor | Monitors the Quadrics switch for problems. | swmlogger |
Table 4-2 lists key HP XC system services, listed alphabetically
by their database name. This list includes third-party services that
have been modified by HP for use in the HP XC system.
Table 4-2 HP XC System Services
| HP XC Service | Function | Database
Name |
|---|
| Console Management Facility Master | Communicates with node consoles. | cmfd |
| Environment Monitoring for DL585 | Environmental monitor for ProLiant DL585
servers only. | hpasm |
| HPC File System Server | Serves the /hptc_cluster file systems. | hptc_cluster_fs |
| HPC File System Client | Mounts the /hptc_cluster file
systems. | hptc_cluster_fs_client |
| License Manager | Manages licenses for HP XC components. | hptc-lm |
| Supermon | (System Monitoring
daemon) Monitors nodes | mond |
| HP MPI system interconnect Setup | Sets up HP-MPI to use the correct
system interconnect for your system. | mpiic |
| Nagios Aggregator | Aggregates information from Nagios daemons on
multiple nodes. | nagios |
| Nagios Remote Plug-In Executor | Executes plug-ins on remote hosts. This
service runs on all nodes. | nrpe |
| Nagios Service | Submits passive service check results to another server
running Nagios. This service runs only on a Nagios master. See Chapter 8 for more information. | nsca |
| Parallel Distributed Shell | High-performance, parallel remote shell
utility | pdsh |
| Power Daemon Server | Manages node power. | powerd |
| Slurm Compute | Runs the slurmd daemon to allow jobs
to be scheduled by SLURM. | slurm_compute |
| Slurm Central Control Service | Manages nodes, partitions, and jobs | slurm_controller |
| Slurm Launch | Allows user to launch jobs on nodes with slurm_compute service. | slurm_launch |
smartd daemon | Monitors the reliability of specific
hard drives on CP6000 systems. | smartd |
| Supermon Aggregator | Gathers information from subordinate nodes running
Supermon. | supermond |
| Image Server | Holds and distributes the system images. | systemimage-server-rsync |
Management hubs are used to aggregate system information
for a set of local nodes. Each management hub runs the following services:
Supermon aggregator
(supermond)
Syslog-ng aggregator (syslogng_forward)
Console
Management Facility (CMF)
“Displaying Services Information” describes commands that provide
information on services, that is, how to display a list of services,
which services are provided on a given node, and which nodes provide
a given service.
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