1. 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.

2. 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.

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

4. 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.

5. FOS Architecture Client PC Accessing web server at 140.113.88.90:80 Active Node Web service running On port 80 Inactive Node Monitors 140.113.88.87:80 Eth0 140.113.88.87 Eth0 140.113.88.84Eth0:1 140.113.88.90 Eth0 140.113.88.93 PRIMARYBACKUP

6. FOS Architecture Client PC Accessing web server at 140.113.88.90:80 Active Node Monitors 140.113.88.84:80 Inactive Node Web service running On port 80 Eth0 140.113.88.87 Eth0 140.113.88.84 Eth0 140.113.88.93 PRIMARYBACKUP Eth0:1 140.113.88.90

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

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

9. 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