Red Hat ENTERPRISE LINUX 4 Manual

Also see for ENTERPRISE LINUX 4 - DEVELOPER TOOLS GUIDE: Installation guide Installation guide Tuning guide Installation guide Manual

Contents

Cluster Components57Function Components Descriptionha/lvs.cf. On the active LVS router,pulse starts the LVS daemon. On thebackup router, pulse determines thehealth of the active router by executing asimple heartbeat at a user-configurableinterval. If the active LVS router failsto respond after a user-configurableinterval, it initiates failover. Duringfailover, pulse on the backup LVSrouter instructs the pulse daemon onthe active LVS router to shut down allLVS services, starts the send_arpprogram to reassign the floating IPaddresses to the backup LVS router'sMAC address, and starts the lvsdaemon.lvsd The lvs daemon runs on the active LVSrouter once called by pulse. It reads theconfiguration file /etc/sysconfig/ha/lvs.cf, calls the ipvsadm utilityto build and maintain the IPVS routingtable, and assigns a nanny processfor each configured LVS service. Ifnanny reports a real server is down,lvs instructs the ipvsadm utility toremove the real server from the IPVSrouting table.ipvsadm This service updates the IPVS routingtable in the kernel. The lvs daemonsets up and administers LVS by callingipvsadm to add, change, or deleteentries in the IPVS routing table.nanny The nanny monitoring daemon runson the active LVS router. Throughthis daemon, the active LVS routerdetermines the health of each real serverand, optionally, monitors its workload. Aseparate process runs for each servicedefined on each real server.lvs.cf This is the LVS configuration file. The fullpath for the file is /etc/sysconfig/ha/lvs.cf. Directly or indirectly,all daemons get their configurationinformation from this file.Piranha Configuration Tool This is the Web-based tool formonitoring, configuring, andadministering LVS. This is the default