High Availability (HA)  Goal : a solution for reliability, availability, and serviceability in Linux.  Focus on the services in the network.  Use the Piranha in the experiment.

Piranha - Red Hat Inc.-  FailOver Service (FOS) 2-node clustering with a floating IP.  Linux Virtual Service (LVS) Include FOS. More than 2 nodes in a cluster. Scheduling. Load-balancing.

An Overview of FOS  2-node clustering : active and standby.  FailOver : the service becomes unresponsive to FOS monitoring.

Features  Possible service : http, ftp, inetd, telnet, smtp, ssh, LDAP, firewall, other IP services.  Not supported service : nfs, ntp.  pop, imap, smtp need a NFS-mounted system.

FOS Architecture Client PC Accessing web server at :80 Active Node Web service running On port 80 Inactive Node Monitors :80 Eth Eth Eth0: Eth PRIMARYBACKUP

FOS Architecture Client PC Accessing web server at :80 Active Node Monitors :80 Inactive Node Web service running On port 80 Eth Eth Eth PRIMARYBACKUP Eth0:

Primary and Backup Nodes  An FOS cluster always have a primary node.  Both nodes declare themselves as active : primary node will always win.

FOS States Active System pulse fos -- active ftp service port 21 Web httpd port 80 Inactive System pulse fos -- monitor nanny Heartbeat Monitor

Conventional High Availability Concept HW I/O Drivers Operating System Application HA Software Administration/ Configuration HW I/O Drivers Operating System HA Software Application Administration/ Configuration Heartbeat and (sometimes) state