Linux Services

SELinux (Security Enhanced Linux) provides mandatory access control to the Linux operating system. SELinux is quite pervasive, even if only in PERMISSIVE mode. This can expose latent bugs in non-SELinux components that are not visible unless SELinux is running. Frustrated users have developed the perception that SELinux is difficult to use. The setroubleshoot service is intended to make SELinux more friendly. It collects SELinux audit events from the kernel and runs a series of analysis … [Read more...] about Linux OS Service ‘setroubleshoot’

The psacct service is responsible for starting and stopping process accounting at system boot time and at system shutdown. This service is a wrapper that invokes the action accounting control program. Service Control To obtain the psacct service, install the psacct RPM package: # yum install psacct To manage the psacct service for automated service start and stop, use the chkconfig tool: # chkconfig psacct on # chkconfig --list psacct psacct 0:off 1:off 2:on 3:on 4:on 5:on 6:off # … [Read more...] about Linux OS Service ‘psacct’

The NetworkManager daemon attempts to keep an active network connection available at all times. The NetworkManager facility offers a tool called NetworkManagerDispatcher which executes commands in /etc/NetworkManager/dispatcher.d according to the changing state of the network interfaces. All scripts in this directory are invoked for every state change of any network interface; the scripts must decide whether to process the event. The companion service NetworkManager must be running to … [Read more...] about Linux OS Service ‘NetworkManagerDispatcher’

The yum-updatesd daemon regularly checks the yum repository and provides notification of updates available for your system. Notifications can be made via syslog, email or dbus, a communication method used between applications. When configured to connect a yum repository, the daemon calls the "yum update" command to update packages on the system. The yum-updatesd service (/etc/init.d/yum-updatesd) is provided by the yum-updatesd package. When started, the service calls /usr/sbin/yum-updatesd, a … [Read more...] about Linux OS Service ‘yum-updatesd’

The acpid daemon supports the Advanced Configuration and Power Interface (ACPI) to allow intelligent power management on your system and to query battery and configuration status. It listens on a file (/proc/acpi/event) and when an event occurs, executes programs to handle the event. Rules are defined by simple configuration files. acpid will look in a configuration directory (/etc/acpi/events by default), and parse all files that do not begin with a period ('.'). Each file must define two … [Read more...] about Linux OS Service ‘acpid’

This executes rpcidmapd, with NFS service. The rpcidmapd maps usernames to UID and GID numbers. Service Control To manage the rpcidmapd service on demand, use the service tool or run the /etc/init.d/rpcidmapd script directly: # /sbin/service rpcidmapd Usage: /etc/init.d/rpcidmapd {start|stop|restart|condstart|condrestart|status} # /etc/init.d/rpcidmapd Usage: /etc/init.d/rpcidmapd {start|stop|restart|condstart|condrestart|status} The available commands are: CommandDescription … [Read more...] about Linux OS Service ‘rpcidmapd’

The avahi-daemon Linux service runs on client machines to perform network-based Zeroconf service discovery. Avahi is an implementation of the DNS Service Discovery and Multicast DNS specifications for Zeroconf Networking. User applications receive notice of discovered network services and resources using the Linux D-Bus message passing. The daemon coordinates application efforts in caching replies, helping minimize network traffic. Avahi provides a set of language bindings, including Python … [Read more...] about Linux OS Service ‘avahi-daemon’

rpc.rusersd is a server which returns information about users currently logged in to the system. The currently logged in users are queried using the rusers command. The rpc.rusersd daemon is normally invoked by inetd. rpc.rusersd uses an RPC protocol defined in /usr/include/rpcsvc/rusers.x. When starting the 'rusersd' service, it first starts the portmap service if not already running, then starts the 'rpc.rusersd' daemon. When stopping the 'rusersd' service, the rpc.rusersd daemon is … [Read more...] about Linux OS Service ‘rusersd’

httpd is the Apache HyperText Transfer Protocol (HTTP) server program. It is designed to be run as a standalone daemon process. When used like this it will create a pool of child processes or threads to handle requests. In general, httpd should not be invoked directly, but rather should be invoked via apachectl on Unix-based systems. The httpd RPM package provides the /usr/sbin/httpd daemon and its configuration files. Service Control To manage the httpd service on demand, use the service … [Read more...] about Linux OS Service ‘httpd’

The scsi_reserve service allows you to use SCSI reservations as a fence method. An SCSI reservation restricts access to a device such that only registered nodes can access it. During system startup, the scsi_reserve script performs this registration using a unique key, based on the node's IP address. Once the node is registered, the script will attempt to create a reservation. There will be only one reservation per SCSI device but multiple registrants can exist for an SCSI device. Each node that … [Read more...] about Linux OS Service ‘scsi_reserve’