Red Hat CLUSTER SUITE FOR ENTERPRISE LINUX 5.2, Overview

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Function Components Description
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.
Cluster Components
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