Red Hat CLUSTER SUITE - CONFIGURING AND MANAGING A CLUSTER 2006 Guida di Installazione

Red Hat Cluster Suitefor RHEL 4Overview

vi About This Document

Chapter 1.Red Hat Cluster Suite OverviewClustered systems provide reliability, scalability, and availability to critical production ser-vices. Using R

2 Chapter 1. Red Hat Cluster Suite OverviewHigh-availability clusters provide continuous availability of services by eliminating singlepoints of failu

Chapter 1. Red Hat Cluster Suite Overview 3• Red Hat GFS (Global File System) — Provides a cluster file system for use with RedHat Cluster Suite. GFS a

4 Chapter 1. Red Hat Cluster Suite Overview1.3. Cluster InfrastructureThe Red Hat Cluster Suite cluster infrastructure provides the basic functions fo

Chapter 1. Red Hat Cluster Suite Overview 5NoteIn a CMAN cluster, by default each node has one quorum vote for establishing quorum.Optionally, you can

6 Chapter 1. Red Hat Cluster Suite OverviewFigure 1-3. GULM Overview1.3.2. Lock ManagementLock management is a common cluster-infrastructure service t

Chapter 1. Red Hat Cluster Suite Overview 7• Configured with CMAN/DLM — fenced, the fence daemon, performs fencing.• Configured with GULM servers — GULM

8 Chapter 1. Red Hat Cluster Suite OverviewFigure 1-4. Power Fencing ExampleFigure 1-5. Fibre Channel Switch Fencing Example

Chapter 1. Red Hat Cluster Suite Overview 9Specifying a fencing method consists of editing a cluster configuration file to assign afencing-method name,

Red Hat Cluster Suitefor RHEL 4: OverviewCopyright © 2000-2006 Red Hat, Inc.Red Hat, Inc.1801 Varsity DriveRaleigh NC 27606-2072 USAPhone: +1 919 754

10 Chapter 1. Red Hat Cluster Suite OverviewFigure 1-7. Fencing a Node with Dual Fibre Channel ConnectionsYou can configure a node with one fencing met

Chapter 1. Red Hat Cluster Suite Overview 11Figure 1-8. CCS OverviewOther cluster components (for example, CMAN) access configuration information fromt

12 Chapter 1. Red Hat Cluster Suite OverviewThe cluster configuration file (/etc/cluster/cluster.conf) is an XML file that de-scribes the following clust

Chapter 1. Red Hat Cluster Suite Overview 13cluster service can start on any cluster node in the event no member of the failover domainis available.)I

14 Chapter 1. Red Hat Cluster Suite OverviewFigure 1-11 shows an example of a high-availability cluster service that is a web servernamed "conten

Chapter 1. Red Hat Cluster Suite Overview 151.5. Red Hat GFSRed Hat GFS is a cluster file system that allows a cluster of nodes to simultaneously acces

16 Chapter 1. Red Hat Cluster Suite OverviewYou can deploy GFS in a variety of configurations to suit your needs for performance,scalability, and econo

Chapter 1. Red Hat Cluster Suite Overview 17Figure 1-12. GFS with a SAN1.5.2. Performance, Scalability, Moderate PriceMultiple Linux client applicatio

18 Chapter 1. Red Hat Cluster Suite OverviewFigure 1-13. GFS and GNBD with a SAN1.5.3. Economy and PerformanceFigure 1-14 shows how Linux client appli

Chapter 1. Red Hat Cluster Suite Overview 19Figure 1-14. GFS and GNBD with Directly Connected Storage1.6. Cluster Logical Volume ManagerThe Cluster Lo

Table of ContentsAbout This Document... i1. Docum

20 Chapter 1. Red Hat Cluster Suite OverviewNoteUsing CLVM requires minor changes to /etc/lvm/lvm.conf for cluster-wide locking.Figure 1-15. CLVM Over

Chapter 1. Red Hat Cluster Suite Overview 21Figure 1-16. LVM Graphical User InterfaceFigure 1-17. Creating Logical Volumes

22 Chapter 1. Red Hat Cluster Suite Overview1.7. Global Network Block DeviceGlobal Network Block Device (GNBD) provides block-device access to Red Hat

Chapter 1. Red Hat Cluster Suite Overview 23• To balance the load across the real servers.• To check the integrity of the services on each real server

24 Chapter 1. Red Hat Cluster Suite Overviewrouter via both the public and private network interfaces to shut down the lvs daemonon the active LVS rou

Chapter 1. Red Hat Cluster Suite Overview 25Figure 1-20. Two-Tier LVS TopologyService requests arriving at an LVS router are addressed to a virtual IP

26 Chapter 1. Red Hat Cluster Suite Overview• Weighted Round-Robin Scheduling — Distributes each request sequentially around apool of real servers but

Chapter 1. Red Hat Cluster Suite Overview 27of the active LVS router. During failover, the backup LVS router takes over the VIP ad-dresses serviced by

28 Chapter 1. Red Hat Cluster Suite OverviewFigure 1-21. Three-Tier LVS TopologyThis topology is suited well for busy FTP servers, where accessible da

Chapter 1. Red Hat Cluster Suite Overview 291.8.3. Routing MethodsYou can use Network Address Translation (NAT) routing or direct routing with LVS. Th

30 Chapter 1. Red Hat Cluster Suite OverviewIP address to its physical device on the LVS router nodes, having more than two NICs isnot a requirement.U

Chapter 1. Red Hat Cluster Suite Overview 31Figure 1-23. LVS Implemented with Direct RoutingIn a typical direct-routing LVS configuration, an LVS route

32 Chapter 1. Red Hat Cluster Suite OverviewThe issue with ARP requests in a direct-routing LVS configuration is that because a clientrequest to an IP

Chapter 1. Red Hat Cluster Suite Overview 331.8.4.2. Firewall MarksFirewall marks are an easy and efficient way to a group ports used for a protocol or

34 Chapter 1. Red Hat Cluster Suite OverviewCommandLine ToolUsed With Purposeccs_tool —ClusterConfigurationSystem ToolClusterInfrastructureccs_tool is

Chapter 1. Red Hat Cluster Suite Overview 351.9.1. Cluster Configuration ToolYou can access the Cluster Configuration Tool (Figure 1-24) through the Clu

36 Chapter 1. Red Hat Cluster Suite Overview• Fence Devices — Displays fence devices. Fence devices are represented as subordinateelements under Fence

Chapter 1. Red Hat Cluster Suite Overview 37Figure 1-25. Cluster Configuration Structure

38 Chapter 1. Red Hat Cluster Suite Overview1.9.2. Cluster Status ToolYou can access the Cluster Status Tool (Figure 1-26) through the Cluster Managem

Chapter 1. Red Hat Cluster Suite Overview 39(Relocating a service to its current node — that is, dragging a service to its current nodeand dropping th

About This DocumentThis document provides a high-level overview of Red Hat Cluster Suite for Red Hat Enter-prise Linux 4. Although the information in

40 Chapter 1. Red Hat Cluster Suite Overview1.10. Linux Virtual Server Administration GUIThis section provides an overview of the LVS configuration too

Chapter 1. Red Hat Cluster Suite Overview 41Figure 1-28. The CONTROL/MONITORING PanelAuto updateEnables the status display to be updated automatically

42 Chapter 1. Red Hat Cluster Suite OverviewFigure 1-29. The GLOBAL SETTINGS PanelThe top half of this panel sets up the primary LVS router’s public a

Chapter 1. Red Hat Cluster Suite Overview 43NAT Router netmaskIf the NAT router’s floating IP needs a particular netmask, select it from drop-downlist.

44 Chapter 1. Red Hat Cluster Suite OverviewRedundant server private IPThe backup router’s private real IP address.The rest of the panel is for configu

Chapter 1. Red Hat Cluster Suite Overview 45Figure 1-31. The VIRTUAL SERVERS PanelEach server displayed in the VIRTUAL SERVERS panel can be configured

46 Chapter 1. Red Hat Cluster Suite OverviewFigure 1-32. The VIRTUAL SERVERS SubsectionNameA descriptive name to identify the virtual server. This nam

Chapter 1. Red Hat Cluster Suite Overview 47Firewall MarkFor entering a firewall mark integer value when bundling multi-port protocols or cre-ating a m

48 Chapter 1. Red Hat Cluster Suite OverviewPersistence Network MaskTo limit persistence to particular subnet, select the appropriate network mask fro

Chapter 1. Red Hat Cluster Suite Overview 49Figure 1-34. The REAL SERVER Configuration PanelThis panel consists of three entry fields:NameA descriptive

ii About This Documentcontains words that would be displayed in a different style on their own (such as filenames). In these cases, they are considered

50 Chapter 1. Red Hat Cluster Suite Overview1.10.4.3. EDIT MONITORING SCRIPTS SubsectionClick on the MONITORING SCRIPTS link at the top of the page. T

Chapter 1. Red Hat Cluster Suite Overview 51SendA string for the nanny daemon to send to each real server in this field. By default thesend field is com

52 Chapter 1. Red Hat Cluster Suite Overview

Chapter 2.Red Hat Cluster Suite ComponentSummaryThis chapter provides a summary of Red Hat Cluster Suite components and consists of thefollowing secti

54 Chapter 2. Red Hat Cluster Suite Component SummaryFunction Components DescriptionClusterConfigurationSystem (CCS)ccs_tool ccs_tool is part of the Cl

Chapter 2. Red Hat Cluster Suite Component Summary 55Function Components Descriptionclurgmgrd Daemon used to handle userservice requests including ser

56 Chapter 2. Red Hat Cluster Suite Component SummaryFunction Components Descriptionfence_egenera Fence agent used with EgeneraBladeFrame system.fence

Chapter 2. Red Hat Cluster Suite Component Summary 57Function Components Descriptiongfs_tool Command that configures or tunesa GFS file system. This com

58 Chapter 2. Red Hat Cluster Suite Component SummaryFunction Components DescriptionLVS pulse This is the controlling processwhich starts all other da

Chapter 2. Red Hat Cluster Suite Component Summary 59Function Components Descriptionnanny The nanny monitoring daemonruns on the active LVS router.Thr

About This Document iiitop level of a menu on a GUI screen or windowA word in this style indicates that the word is the top level of a pulldown menu.

60 Chapter 2. Red Hat Cluster Suite Component Summary• cluster.conf [cluster] (5) - The configuration file for cluster products• QDisk 1.0 [qdisk] (5) -

Chapter 2. Red Hat Cluster Suite Component Summary 61• gfs_quota (8) - Manipulate GFS disk quotas• gfs_tool (8) - interface to gfs ioctl calls• Cluste

62 Chapter 2. Red Hat Cluster Suite Component Summary

IndexAabout this document, iother Red Hat Enterprise Linux documents, iCclusterdisplaying status, 39cluster administrationdisplaying cluster and servi

64Sservices status table, 39Ttablecommand line tools, 33tablescluster components, 53members status, 39services status, 39

iv About This Document<replaceable>Text used in examples that is meant to be replaced with data provided by the useris displayed in this style.

About This Document vWarningBe careful to remove only the necessary partitions. Removing other partitions could resultin data loss or a corrupted syst