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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