2.1. Cluster Components

2.1. Cluster Components

Table 2.1, “Red Hat Cluster Suite Software Subsystem Components” summarizes Red Hat Cluster Suite components.

Function Components Description
Conga luci Remote Management System - Management Station.
ricci Remote Management System - Managed Station.
Cluster Configuration Tool system-config-cluster Command used to manage cluster configuration in a graphical setting.
Cluster Logical Volume Manager (CLVM) clvmd The daemon that distributes LVM metadata updates around a cluster. It must be running on all nodes in the cluster and will give an error if a node in the cluster does not have this daemon running.
lvm LVM2 tools. Provides the command-line tools for LVM2.
system-config-lvm Provides graphical user interface for LVM2.
lvm.conf The LVM configuration file. The full path is /etc/lvm/lvm.conf.
Cluster Configuration System (CCS) ccs_tool ccs_tool is part of the Cluster Configuration System (CCS). It is used to make online updates of CCS configuration files. Additionally, it can be used to upgrade cluster configuration files from CCS archives created with GFS 6.0 (and earlier) to the XML format configuration format used with this release of Red Hat Cluster Suite.
ccs_test Diagnostic and testing command that is used to retrieve information from configuration files through ccsd.
ccsd CCS daemon that runs on all cluster nodes and provides configuration file data to cluster software.
cluster.conf This is the cluster configuration file. The full path is /etc/cluster/cluster.conf.
Cluster Manager (CMAN) cman.ko The kernel module for CMAN.
cman_tool This is the administrative front end to CMAN. It starts and stops CMAN and can change some internal parameters such as votes.
dlm_controld Daemon started by cman init script to manage dlm in kernel; not used by user.
gfs_controld Daemon started by cman init script to manage gfs in kernel; not used by user.
group_tool Used to get a list of groups related to fencing, DLM, GFS, and getting debug information; includes what cman_tool services provided in RHEL 4.
groupd Daemon started by cman init script to interface between openais/cman and dlm_controld/gfs_controld/fenced; not used by user.
libcman.so.<version number> Library for programs that need to interact with cman.ko.
Resource Group Manager (rgmanager) clusvcadm Command used to manually enable, disable, relocate, and restart user services in a cluster.
clustat Command used to display the status of the cluster, including node membership and services running.
clurgmgrd Daemon used to handle user service requests including service start, service disable, service relocate, and service restart.
clurmtabd Daemon used to handle Clustered NFS mount tables.
Fence fence_apc Fence agent for APC power switch.
fence_bladecenter Fence agent for for IBM Bladecenters with Telnet interface.
fence_bullpap Fence agent for Bull Novascale Platform Administration Processor (PAP) Interface.
fence_drac Fencing agent for Dell Remote Access Card.
fence_ipmilan Fence agent for machines controlled by IPMI (Intelligent Platform Management Interface) over LAN.
fence_wti Fence agent for WTI power switch.
fence_brocade Fence agent for Brocade Fibre Channel switch.
fence_mcdata Fence agent for McData Fibre Channel switch.
fence_vixel Fence agent for Vixel Fibre Channel switch.
fence_sanbox2 Fence agent for SANBox2 Fibre Channel switch.
fence_ilo Fence agent for HP ILO interfaces (formerly fence_rib).
fence_rsa I/O Fencing agent for IBM RSA II.
fence_gnbd Fence agent used with GNBD storage.
fence_scsi I/O fencing agent for SCSI persistent reservations.
fence_egenera Fence agent used with Egenera BladeFrame system.
fence_manual Fence agent for manual interaction. NOTE This component is not supported for production environments.
fence_ack_manual User interface for fence_manual agent.
fence_node A program which performs I/O fencing on a single node.
fence_xvm I/O Fencing agent for Xen virtual machines.
fence_xvmd I/O Fencing agent host for Xen virtual machines.
fence_tool A program to join and leave the fence domain.
fenced The I/O Fencing daemon.
DLM libdlm.so.<version number> Library for Distributed Lock Manager (DLM) support.
GFS gfs.ko Kernel module that implements the GFS file system and is loaded on GFS cluster nodes.
gfs_fsck Command that repairs an unmounted GFS file system.
gfs_grow Command that grows a mounted GFS file system.
gfs_jadd Command that adds journals to a mounted GFS file system.
gfs_mkfs Command that creates a GFS file system on a storage device.
gfs_quota Command that manages quotas on a mounted GFS file system.
gfs_tool Command that configures or tunes a GFS file system. This command can also gather a variety of information about the file system.
mount.gfs Mount helper called by mount(8); not used by user.
GNBD gnbd.ko Kernel module that implements the GNBD device driver on clients.
gnbd_export Command to create, export and manage GNBDs on a GNBD server.
gnbd_import Command to import and manage GNBDs on a GNBD client.
gnbd_serv A server daemon that allows a node to export local storage over the network.
LVS pulse This is the controlling process which starts all other daemons related to LVS routers. At boot time, the daemon is started by the /etc/rc.d/init.d/pulse script. It then reads the configuration file /etc/sysconfig/ha/lvs.cf. On the active LVS router, pulse starts the LVS daemon. On the backup router, pulse determines the health of the active router by executing a simple heartbeat at a user-configurable interval. If the active LVS router fails to respond after a user-configurable interval, it initiates failover. During failover, pulse on the backup LVS router instructs the pulse daemon on the active LVS router to shut down all LVS services, starts the send_arp program to reassign the floating IP addresses to the backup LVS router's MAC address, and starts the lvs daemon.
lvsd The lvs daemon runs on the active LVS router once called by pulse. It reads the configuration file /etc/sysconfig/ha/lvs.cf, calls the ipvsadm utility to build and maintain the IPVS routing table, and assigns a nanny process for each configured LVS service. If nanny reports a real server is down, lvs instructs the ipvsadm utility to remove the real server from the IPVS routing table.
ipvsadm This service updates the IPVS routing table in the kernel. The lvs daemon sets up and administers LVS by calling ipvsadm to add, change, or delete entries in the IPVS routing table.
nanny The nanny monitoring daemon runs on the active LVS router. Through this daemon, the active LVS router determines the health of each real server and, optionally, monitors its workload. A separate process runs for each service defined on each real server.
lvs.cf This is the LVS configuration file. The full path for the file is /etc/sysconfig/ha/lvs.cf. Directly or indirectly, all daemons get their configuration information from this file.
Piranha Configuration Tool This is the Web-based tool for monitoring, configuring, and administering LVS. This is the default tool to maintain the /etc/sysconfig/ha/lvs.cf LVS configuration file.
send_arp This program sends out ARP broadcasts when the floating IP address changes from one node to another during failover.
Quorum Disk qdisk A disk-based quorum daemon for CMAN / Linux-Cluster.
mkqdisk Cluster Quorum Disk Utility.
qdiskd Cluster Quorum Disk Daemon.
Table 2.1. Red Hat Cluster Suite Software Subsystem Components


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