List of Figures

Introduction

Figure 1: Simplified architecture of a single computer

Figure 2: Simplified architecture of an enterprise cluster

Figure 3: Enterprise cluster with no single point of failure

Chapter 2: Handling Packets

Figure 2-1: The five Netfilter hooks in the Linux kernel

Figure 2-2: ipchains in the Linux kernel

Figure 2-3: iptables in the Linux kernel

Figure 2-4: Linux firewall and router example network

Chapter 4: Synchronizing Servers with RYSNC and SSH

Figure 4-1: rsync and SSH

Figure 4-2: SSH client connection request

Figure 4-3: SSH server response

Figure 4-4: The SSH client searches for the SSH server name in its known_hosts database

Figure 4-5: The SSH client and SSH server establish an SSH transport

Chapter 5: Cloning Systems with Systemimager

Figure 5-1: The SystemImager server and Golden Client

Figure 5-2: Software used on SystemImager server, Golden Client, and clone(s)

Chapter 6: Heartbeat Introduction and Theory

Figure 6-1: Physical paths for heartbeats

Figure 6-2: A basic Heartbeat configuration

Figure 6-3: The same basic Heartbeat configuration after failure of the primary server

Chapter 7: A Sample Heartbeat Configuration

Figure 7-1: The Heartbeat network configuration

Chapter 8: Heartbeat Resources and Maintenance

Figure 8-1: Heartbeat active-active configuration

Chapter 9: Stonith and Ipfail

Figure 9-1: Two-server Heartbeat with Stonith—normal operation

Figure 9-2: Stonith sequence of events

Chapter 11: The Linux Virtual Server: Introduction and Theory

Figure 11-1: LVS cluster schematic

Figure 11-2: LVS-NAT network communication

Figure 11-3: LVS-DR network communication

Figure 11-4: LVS-TUN network communication

Chapter 12: The LVS-NAT Cluster

Figure 12-1: In packet 1 the client computer sends a request to the LVS-NAT cluster

Figure 12-2: In packet 2 the Director forwards the client computer's request to a cluster node

Figure 12-3: In packet 3 the cluster node sends a reply back through the Director

Figure 12-4: In packet 4 the Director forwards the reply packet to the client computer

Figure 12-5: An LVS-NAT cluster with multiple VIPs

Figure 12-6: Multiple VIPs and their relationship with the multiple virtual RIPs

Figure 12-7: LVS-NAT web cluster

Chapter 13: The LVS-DR Cluster

Figure 13-1: In packet 1 the client sends a request to the LVS-DR cluster

Figure 13-2: In packet 2 the Director forwards the client computer's request to a cluster node

Figure 13-3: In packet 3 the cluster node sends a reply back through the Director

Figure 13-4: An ARP broadcast to an LVS-DR cluster

Figure 13-5: An ARP response from the LVS-DR Director

Chapter 14: The Load Balancer

Figure 14-1: Incoming packets inside the Director

Figure 14-2: Outgoing LVS-NAT packets inside the Director

Figure 14-3: Netfilter Marked Packets and LVS

Chapter 15: The High-Availability Cluster

Figure 15-1: A highly available DR cluster

Figure 15-2: ldirectord requests a health check URL

Figure 15-3: Real server 1 sends back the reply

Figure 15-4: Failure of primary Director

Chapter 16: The Network File System

Figure 16-1: Ethernet performance bottlenecks

Chapter 17: The Simple Network Management Protocol and Mon

Figure 17-1: Mon and snmpd for cluster monitoring

Figure 17-2: Mon examines the MIB of each cluster node

Chapter 18: Ganglia

Figure 18-1: The Ganglia Web package title section

Figure 18-2: The Ganglia Web package node snapshot section

Figure 18-3: The Host Report Title Section

Figure 18-4: The Host Report overview section

Chapter 19: Case Studies in Cluster Administration

Figure 19-1: LPRng in a cluster environment

Chapter 20: The Linux Cluster Environment

Figure 20-1: Figure of a ten-node cluster with a KVM device

Figure 20-2: High-availability cluster node manager

Figure 20-3: High-availability LTSP servers and Thin Clients

Figure 20-4: High-availability NAS server

Figure 20-5: Serial-to-IP communication devices

Figure 20-6: A highly available database server

Figure 20-7: The Linux Enterprise Cluster