Load Balancer Administration Guide

(1)

WebSphere

Application

Server

Load

Balancer

Administration

Guide

Version

6.0.2

GC31-6858-02

(2)

(3)

WebSphere

Application

Server

Load

Balancer

Administration

Guide

Version

6.0.2

GC31-6858-02

(4)

Note

Beforeusingthisinformationandtheproductitsupports,besuretoreadthegeneralinformationunderAppendixE, “Notices,”onpage439.

Thirdedition(June2005) Thiseditionappliesto:

WebSphereApplicationServer,Version6.0.2

andtoallsubsequentreleasesandmodificationsuntilotherwiseindicatedinneweditions.

OrderpublicationsthroughyourIBMrepresentativeorthroughtheIBMbranchofficeservingyourlocality. ©CopyrightInternationalBusinessMachinesCorporation2005.Allrightsreserved.

(5)

Contents

Tables

.

. xi

Figures

.

. xiii

About

this

book

.

. xv

Whoshouldreadthisbook . . . xv

ReferenceInformation. . . xv

Accessibility . . . xv

Howtosendyourcomments . . . xv

and

Web

sites

xvii

Part

1.

Introducing

Load

Balancer

.

. 1

Chapter

1.

Overview

of

Load

Balancer

.

. 3

WhatisLoadBalancer?. . . 3

Whichcomponent(s)ofLoadBalancercanIuse? . . 3

WhataretheadvantagestousingLoadBalancer? . . 4

Howabouthighavailability? . . . 5

Dispatcher . . . 5

CBRorSiteSelector . . . 6

CiscoCSSControllerorNortelAlteonController 6 Newfeatures . . . 6

Newfeaturesfor6.0.2 . . . 6

Newfeaturesfor6.0. . . 7

Chapter

2.

Overview

of

the

components

of

Load

Balancer

.

. 13

WhatarethecomponentsofLoadBalancer? . . . 13

OverviewoftheDispatchercomponent . . . 13

ManaginglocalserverswithDispatcher . . . . 14

ManagingserversusingDispatcherandMetric Server . . . 15

Managinglocalandremoteserverswith Dispatcher. . . 15

OverviewoftheContentBasedRouting(CBR) component . . . 16

ManaginglocalserverswithCBR . . . 16

OverviewoftheSiteSelectorcomponent . . . . 17

ManaginglocalandremoteserverswithSite SelectorandMetricServer . . . 18

OverviewoftheCiscoCSSControllercomponent 18 OverviewofNortelAlteonControllercomponent . 20

Chapter

3.

Managing

your

network:

Determining

which

Load

Balancer

features

to

use

.

. 23

Manager,Advisors,andMetricServerfunctions(for Dispatcher,CBR,andSiteSelectorcomponents) . . 23

Dispatchercomponentfeatures . . . 23

Remoteadministration . . . 23

Collocation . . . 23

Highavailability. . . 23

Clienttoserveraffinity . . . 24

Rules-basedloadbalancing . . . 24

Content-basedroutingusingDispatcher’scbr forwardingmethod. . . 25

Widearealoadbalancing. . . 25

Portmapping. . . 26

SettingupDispatcheronaprivatenetwork . . 26

Wildcardclusterandwildcardport . . . 26

″Denialofservice″attackdetection . . . 26

Binarylogging . . . 26

Alerts . . . 26

ContentBasedRouting(CBR)componentfeatures 26 ComparisonbetweentheCBRcomponentand theDispatchercomponent’scbrforwarding method. . . 27

CBRwithmultipleinstancesofCachingProxy . 27

Providecontent-basedroutingforSSL connections . . . 27

Serverpartitioning . . . 27

HighavailabilityusingDispatcherandCBR . . 28

Alerts . . . 28

SiteSelectorcomponentfeatures . . . 29

Widearealoadbalancing. . . 29

Alerts . . . 30

CiscoCSSControllercomponentfeatures . . . . 30

Alerts . . . 30

NortelAlteonControllercomponentfeatures . . . 31

Alerts . . . 31

Chapter

4.

Installing

Load

Balancer

.

. 33

AIXsystemrequirementsandinstallation . . . . 33

(6)

RequirementsforAIX . . . 33

InstallingforAIX . . . 33

Beforeyouinstall . . . 34

Installationsteps. . . 34

HP-UXsystemrequirementsandinstallation . . . 36

RequirementsforHP-UX . . . 36

InstallingforHP-UX . . . 36

Linuxsystemrequirementsandinstallation. . . . 38

RequirementsforLinux . . . 38

InstallingforLinux. . . 38

Solarissystemrequirementsandinstallation . . . 40

RequirementsforSolaris . . . 40

InstallingforSolaris . . . 40

Windowssystemrequirementsandinstallation . . 41

RequirementsforWindows . . . 41

InstallingforWindows . . . 41

Part

2.

Dispatcher

component

.

. 43

Chapter

5.

Quick

start

configuration

.

. 45

Whatwillyouneed? . . . 45

Howdoyouprepare? . . . 46

ConfiguringtheDispatchercomponent . . . 47

Configuringusingthecommandline. . . 47

Testingyourconfiguration . . . 47

Configuringusingthegraphicaluserinterface (GUI) . . . 47

ConfigurationWizard . . . 48

Typesofcluster,port,serverconfigurations. . . . 48

Chapter

6.

Planning

for

Dispatcher

.

. 51

Planningconsiderations . . . 51

Forwardingmethods . . . 52

Dispatcher’sMAC-levelrouting(macforwarding method) . . . 52

Dispatcher’sNAT/NAPT(natforwarding method) . . . 53

Dispatcher’scontent-basedrouting(cbr forwardingmethod) . . . 54

SamplestepsforconfiguringDispatcher’snator cbrforwardingmethods . . . 56

ServerPartitioning:logicalserversconfiguredtoone physicalserver(IPaddress) . . . 57

ServerpartitioningusingHTTPorHTTPS advisors . . . 57

Exampleforconfiguringaphysicalserverinto logicalservers . . . 58

Simplehighavailability . . . 59

Mutualhighavailability . . . 60

Chapter

7.

Configuring

Dispatcher

.

. 61

Overviewofconfigurationtasks . . . 61

Methodsofconfiguration. . . 61

Commandline . . . 61

Scripts . . . 62

GUI . . . 62

Configuringusingtheconfigurationwizard . . 63

SettinguptheDispatchermachine. . . 64

Step1.Starttheserverfunction. . . 65

Step2.Starttheexecutorfunction . . . 66

Step3.Definethenonforwardingaddress(if differentfromhostname) . . . 66

Step4.Defineaclusterandsetclusteroptions . 66

Step5.Aliasthenetworkinterfacecard . . . . 66

Step6.Defineportsandsetportoptions . . . 67

Step7.Defineload-balancedservermachines . . 68

Step8.Startthemanagerfunction(optional) . . 68

Step9.Starttheadvisorfunction(optional). . . 68

Step10.Setclusterproportionsasrequired. . . 68

Settingupservermachinesforloadbalancing. . . 69

Step1.Aliastheloopbackdevice . . . 69

Step2.Checkforanextraroute . . . 71

Step3.Deleteanyextraroute . . . 72

Step4.Verifyserverisproperlyconfigured. . . 73

Linuxloopbackaliasingalternativeswhenusing LoadBalancer’smacforwarding . . . 73

Chapter

8.

Deploying

Dispatcher

on

Load

Balancer

for

IPv6

.

. 77

SupportedplatformsforLoadBalancerforIPv6 . . 77

InstallingLoadBalancerforIPv6 . . . 78

Specialconfigurationconsiderationsandlimitations forLoadBalancerforIPv6 . . . 78

Homogeneouscluster/serverpairs . . . 78

Dispatcherfeaturesnotsupported. . . 78

Configuringhighavailability . . . 79

Collocatingservers . . . 79

Configuringadvisors . . . 79

ConfiguringMetricServer . . . 79

EnableprocessingofIPv6packetsonLoadBalancer forIPv6 . . . 80

AliasingtheinterfacedeviceonLoadBalancerfor IPv6. . . 80

Dispatchercommands(dscontrol)forLoadBalancer forIPv6 . . . 82

Commandsyntaxdifferences . . . 82

Supporteddscontrolcommands . . . 82

Unsupporteddscontrolcommands . . . 84

Part

3.

Content

Based

Routing

(CBR)

component

.

. 85

Chapter

9.

Quick

start

configuration

.

. 87

Whatyouwillneed? . . . 87

ConfiguringtheCBRcomponent . . . 88

Configuringusingthecommandline. . . 88

(7)

Typesofcluster,port,serverconfigurations. . . . 90

Chapter

10.

Planning

for

Content

Based

Routing

.

. 93

Loadbalancingrequestsfordifferenttypesof content . . . 94

Dividingyoursite’scontentforbetterresponse time . . . 94

ProvidingbackupofWebservercontent. . . . 94

UsingmultipleCachingProxyprocessesto improveCPUutilization . . . 94

Usingrules-basedloadbalancingwithCBR . . 95

Loadbalancingacrossfullysecure(SSL) connections . . . 95

Loadbalancingclient-to-proxyinSSLand proxy-to-serverinHTTP . . . 95

Chapter

11.

Configuring

Content

Based

Routing

.

. 97

Methodsofconfiguration. . . 97

Scripts . . . 99

GUI . . . 99

Configurationwizard. . . 100

SettinguptheCBRmachine . . . 101

Step1.ConfigureCachingProxytouseCBR 101 Step2.Starttheserverfunction . . . 102

Step3.Starttheexecutorfunction . . . 102

Step4.Defineaclusterandsetclusteroptions 103 Step5.Aliasthenetworkinterfacecard (optional). . . 103

Step6.Defineportsandsetportoptions . . . 104

Step7.Defineloadbalancedservermachines 104 Step8.Addrulestoyourconfiguration . . . 104

Step9.Addserverstoyourrules. . . 105

Step10.Startthemanagerfunction(optional) 105 Step11.Starttheadvisorfunction(optional) . . 105

Step12.Setclusterproportionsasrequired . . 105

Step13.StartCachingProxy . . . 105

CBRconfigurationexample. . . 105

Part

4.

Site

Selector

component

107

Chapter

12.

Quick

start

configuration

109

ConfiguringtheSiteSelectorcomponent . . . . 110

Configuringusingthecommandline . . . . 110

Chapter

13.

Planning

for

Site

Selector

113

PlanningConsiderations. . . 113

TTLconsiderations . . . 115

UsingtheNetworkProximityfeature . . . . 115

Chapter

14.

Configuring

Site

Selector

117

Methodsofconfiguration . . . 117

Scripts. . . 118

GUI . . . 118

Configurationwizard. . . 119

SettinguptheSiteSelectormachine. . . 120

Step1.Starttheserverfunction . . . 120

Step2.StarttheNameServer . . . 120

Step3.Defineasitenameandsetsitename options . . . 120

Step4.Defineloadbalancedservermachines 120 Step5.Startthemanagerfunction(optional) 121 Step6.Starttheadvisorfunction(optional) . . 121

Step7.Definesystemmetric(optional). . . . 121

Step8.Setsitenameproportionsasrequired 121 Settingupservermachinesforloadbalancing . . 121

Part

5.

Cisco

CSS

Controller

component

.

. 123

Chapter

15.

Quick

start

configuration

125

ConfiguringtheCiscoCSSControllercomponent 126 Configuringusingthecommandline . . . . 126

Chapter

16.

Planning

for

Cisco

CSS

Controller

.

. 129

Systemrequirements . . . 129

Placementoftheconsultantinthenetwork . . 130

Highavailability . . . 132

Calculatingweights . . . 132

Problemdetermination . . . 133

Chapter

17.

Configuring

Cisco

CSS

Controller

.

. 135

XML . . . 136

GUI . . . 137

SettinguptheControllerforCiscoCSSSwitches machine . . . 138

Step2.Startthecommandlineinterface . . . 138

Step3.Configuretheconsultant . . . 138

Step3.Configureanownercontent . . . 138

Step4.Verifythatservicesarecorrectlydefined 138 Step5.Configuremetrics . . . 138

Step6.Starttheconsultant . . . 139

Step7.StarttheMetricServer(optional) . . . 139

(8)

Step8.Configurehighavailability(optional) 139

Part

6.

Nortel

Alteon

Controller

component

.

. 141

Chapter

18.

Quick

start

configuration

143

ConfiguringtheNortelAlteonController component . . . 144

Configuringusingthecommandline . . . . 144

Chapter

19.

Planning

for

Nortel

Alteon

Controller

.

. 147

Systemrequirements . . . 147

Placementoftheconsultantinthenetwork . . 148

Serverattributesontheswitch(setbythe controller) . . . 150

Configuringbackupservers . . . 150

Configuringgroups . . . 151

Tuning . . . 153

Problemdetermination . . . 154

Chapter

20.

Configuring

Nortel

Alteon

Controller

.

. 155

XML . . . 156

GUI . . . 156

SettingupNortelAlteonController . . . 157

Step2.Startthecommandlineinterface . . . 158

Step3.DefineaNortelAlteonWebSwitch consultant . . . 158

Step4.Addaservicetotheswitchconsultant 158 Step5.Configuremetrics . . . 158

Step6.Starttheconsultant . . . 158

Step7.Configurehighavailability(optional) 159 Step8.StarttheMetricServer(optional) . . . 159

Step9.RefreshingtheNortelAlteonController configuration . . . 159

Part

7.

Functions

and

advanced

features

for

Load

Balancer

.

. 161

Chapter

21.

Manager,

Advisors,

and

Metric

Server

functions

for

Dispatcher,

CBR,

and

Site

Selector

.

. 163

OptimizingtheloadbalancingprovidedbyLoad Balancer . . . 164

Proportionofimportancegiventostatus information . . . 164

Weights . . . 165

Managerintervals . . . 166

Sensitivitythreshold . . . 167

Smoothingindex . . . 167

Usingscriptstogenerateanalertorrecord serverfailure . . . 167

Advisors . . . 168

Howadvisorswork . . . 169

Startingandstoppinganadvisor. . . 169

Advisorintervals . . . 170

Advisorreporttimeout . . . 170

Advisorconnecttimeoutandreceivetimeoutfor servers . . . 171

Advisorretry . . . 171

Listofadvisors. . . 171

ConfiguringtheHTTPorHTTPSadvisorusing therequest/response(URL)option . . . 173

UsingSelfAdvisorinatwo-tieredWAN configuration . . . 174

Createcustom(customizable)advisors . . . 175

WASadvisor . . . 176 NamingConvention . . . 176 Compilation. . . 176 Run . . . 177 Requiredroutines . . . 177 Searchorder. . . 177

Namingandpath . . . 178

Sampleadvisor. . . 178

MetricServer . . . 178

WLMRestriction . . . 178

Prerequisites. . . 178

HowtoUseMetricServer . . . 178

WorkloadManageradvisor. . . 180

MetricServerRestriction . . . 180

Chapter

22.

Advanced

features

for

Dispatcher,

CBR,

and

Site

Selector

.

. 183

Usingcollocatedservers. . . 184

FortheDispatchercomponent. . . 184

FortheCBRcomponent. . . 185

FortheSiteSelectorcomponent . . . 186

Configurehighavailability . . . 186

Failuredetectioncapabilityusingheartbeatand reachtarget . . . 188

RecoveryStrategy . . . 189

Usingscripts . . . 189

Configurerules-basedloadbalancing . . . 192

Howarerulesevaluated? . . . 193

UsingrulesbasedontheclientIPaddress. . . 193

Usingrulesbasedontheclientport. . . 193

Usingrulesbasedonthetimeofday . . . . 194

Usingrulesbasedontypeofservice(TOS) . . 194

Usingrulesbasedontheconnectionsper second . . . 194

Usingrulesbasedonthetotalactive connections . . . 195

Usingrulesbasedonreservedbandwidthand sharedbandwidth. . . 195

(9)

Metricallrule . . . 197

Metricaveragerule . . . 197

Usingrulesthatarealwaystrue . . . 197

Usingrulesbasedontherequestcontent . . . 198

portaffinityoverride . . . 198

Addingrulestoyourconfiguration . . . 199

Serverevaluationoptionforrules . . . 199

HowaffinityfeatureforLoadBalancerworks . . 200

Behaviorwhenaffinityisdisabled . . . 200

Behaviorwhenaffinityisenabled . . . 200

Crossportaffinity. . . 201

Affinityaddressmask(stickymask) . . . 201

Quiesceserverconnectionhandling . . . 202

Affinityoptionontherulebasedonthecontentof theclientrequest . . . 203

Activecookieaffinity. . . 203

Passivecookieaffinity . . . 205

URIaffinity . . . 205

ConfigurewideareaDispatchersupport . . . . 206

CommandSyntax . . . 207

UsingremoteadvisorswithDispatcher’swide areasupport. . . 208

Configurationexample . . . 210

GRE(GenericRoutingEncapsulation)support 212 Usingexplicitlinking. . . 213

Usingaprivatenetworkconfiguration . . . 213

Usewildcardclustertocombineserver configurations . . . 214

Usewildcardclustertoloadbalancefirewalls . . 214

UsewildcardclusterwithCachingProxyfor transparentproxy . . . 215

Usewildcardporttodirectunconfiguredport traffic . . . 215

WildcardporttohandleFTPtraffic . . . 216

Denialofserviceattackdetection. . . 216

Usingbinaryloggingtoanalyzeserverstatistics 217

Chapter

23.

Advanced

features

for

Cisco

CSS

Controller

and

Nortel

Alteon

Controller

.

. 219

Collocation . . . 219 Highavailability . . . 219 Configuration . . . 220 Failuredetection . . . 221 Recoverystrategy . . . 221 Examples. . . 221

OptimizingtheloadbalancingprovidedbyLoad Balancer . . . 222

Importancegiventometricinformation . . . 222

Weights . . . 222

Weightcalculationsleeptimes . . . 223

Sensitivitythreshold . . . 223

Advisors . . . 223

Howadvisorswork . . . 224

Advisorsleeptimes . . . 224

Advisorconnecttimeoutandreceivetimeoutfor servers . . . 224

Advisorretry . . . 225

Createcustom(customizable)advisors . . . 225

NamingConvention . . . 226

Compilation. . . 226

Run . . . 227

Requiredroutines . . . 227

Searchorder. . . 227

Namingandpath . . . 228

MetricServer . . . 228

Prerequisites. . . 228

HowtoUseMetricServer . . . 228

Workloadmanageradvisor. . . 230

Usingbinaryloggingtoanalyzeserverstatistics 230 Usingscriptstogenerateanalertorrecordserver failure. . . 232

Part

8.

Administering

and

troubleshooting

Load

Balancer

.

. 233

Chapter

24.

Operating

and

managing

Load

Balancer

.

. 235

RemoteadministrationofLoadBalancer . . . . 235

RemoteMethodInvocation(RMI) . . . 236

Web-basedadministration . . . 237

UsingLoadBalancerlogs . . . 239

ForDispatcher,CBR,andSiteSelector . . . . 239

ForCiscoCSSControllerandNortelAlteon Controller . . . 240

UsingtheDispatchercomponent . . . 241

StartingandStoppingDispatcher. . . 241

Usingstaletimeoutvalue . . . 241

Usingfintimeoutandstaletimeouttocontrol cleanupofconnectionrecords . . . 242

ReportingGUI—theMonitormenuoption . . 242

UsingSimpleNetworkManagementProtocol withtheDispatchercomponent . . . 242

Usingipchainsoriptablestorejectalltrafficto (harden)theLoadBalancermachine(Linux) . . 249

UsingtheContentBasedRoutingcomponent. . . 249

StartingandStoppingCBR. . . 250

ControllingCBR . . . 250

UsingCBRlogs . . . 250

UsingtheSiteSelectorcomponent . . . 250

StartingandstoppingSiteSelector . . . 250

ControllingSiteSelector. . . 250

UsingSiteSelectorlogs . . . 250

UsingtheCiscoCSSControllercomponent . . . 251

StartingandstoppingCiscoCSSController . . 251

ControllingCiscoCSSController . . . 251

UsingCiscoCSSControllerlogs . . . 251

UsingtheNortelAlteonControllercomponent . . 251

StartingandstoppingNortelAlteonController 251 ControllingNortelAlteonController . . . . 251

UsingNortelAlteonControllerlogs . . . 251

UsingtheMetricServercomponent . . . 251

StartingandstoppingMetricServer . . . 251

UsingMetricServerlogs . . . 252

Chapter

25.

Troubleshooting

.

. 253

Gatheringtroubleshootinginformation . . . 253

Generalinformation(alwaysrequired) . . . . 253

(10)

Highavailability(HA)problems . . . 254

Advisorproblems . . . 254

ContentBasedRoutingproblems. . . 255

Notabletohitthecluster . . . 256

Allelsefails. . . 256

Upgrades. . . 256

Javacode. . . 257

Helpfullinks . . . 257

Troubleshootingtables . . . 257

CheckingDispatcherportnumbers . . . 266

CheckingCBRportnumbers . . . 267

CheckingSiteSelectorportnumbers . . . 268

CheckingCiscoCSSControllerportnumbers. . . 268

CheckingNortelAlteonControllerportnumbers 269 Solvingcommonproblems—Dispatcher . . . . 270

Problem:Dispatcherwillnotrun. . . 270

Problem:Dispatcherandserverwillnotrespond 270 Problem:Dispatcherrequestsarenotbeing balanced . . . 270

Problem:Dispatcherhigh-availabilityfunctionis notworking. . . 270

Problem:Unabletoaddheartbeat(Windows platform). . . 271

Problem:Extraroutes(Windows2000) . . . . 271

Problem:Advisorsnotworkingcorrectly . . . 271

Problem:Dispatcher,MicrosoftIIS,andSSLdo notwork(Windowsplatform). . . 271

Problem:Dispatcherconnectiontoaremote machine . . . 271

Problem:dscontrolorlbadmincommandfails 272 Problem:“Cannotfindthefile...″errormessage whentryingtoviewonlineHelp(Windows platform). . . 272

Problem:Graphicaluserinterface(GUI)does notstartcorrectly . . . 273

Problem:ErrorrunningDispatcherwith CachingProxyinstalled . . . 273

Problem:Graphicaluserinterface(GUI)does notdisplaycorrectly . . . 273

Problem:OnWindowsplatform,helpwindows sometimesdisappearbehindotheropen windows . . . 273

Problem:LoadBalancercannotprocessand forwardaframe . . . 273

Problem:Abluescreendisplayswhenyoustart theLoadBalancerexecutor. . . 274

Problem:PathtoDiscoverypreventsreturn trafficwithLoadBalancer . . . 274

Problem:Advisorsshowthatallserversare downwhentaskoffloadenabled(Windows platform). . . 274

Problem:HighavailabilityintheWideArea modeofLoadBalancerdoesnotwork . . . . 275

Problem:GUIhangs(orunexpectedbehavior) whentryingtoloadalargeconfigurationfile. . 275

Problem:lbadmindisconnectsfromserverafter updatingconfiguration . . . 276

Problem:IPaddressesnotresolvingcorrectly overtheremoteconnection. . . 276

Problem:KoreanLoadBalancerinterface displaysoverlappingorundesirablefontson AIXandLinux . . . 276

Problem:OnWindows,aliasaddressisreturned insteadoflocaladdresswhenissuing commandssuchashostname . . . 277

Problem:OnWindowsplatform,unexpected GUIbehaviorwhenusingMatroxAGPvideo cards . . . 277

Problem:Unexpectedbehaviorwhenexecuting ″rmmodibmlb″(Linux) . . . 277

Problem:Slowresponsetimerunning commandsonDispatchermachine . . . 278

Problem:SSLorHTTPSadvisornotregistering serverloads(whenusingmac-forwarding) . . 278

Problem:Disconnectfromhostoccurswhen resizeNetscapebrowserwindowwhileusing Webadministration . . . 278

Problem:SocketpoolingisenabledandtheWeb serverisbindingto0.0.0.0 . . . 278

Problem:OnWindows,corruptedLatin-1 nationalcharactersappearincommandprompt window . . . 279

Problem:OnHP-UX,Javaoutofmemory/ threaderroroccurs . . . 279

Problem:OnWindows,advisorsandreach targetsmarkallserversdown . . . 280

Problem:OnWindows,resolvingIPaddressto hostnamewhenmorethanoneaddressis configuredtoanadapter . . . 280

Problem:OnWindows,afternetworkoutage, advisorsnotworkinginahighavailability setup . . . 281

Problem:OnLinux,donotuse″IPaddressadd″ commandwhenaliasingmultipleclusterson theloopbackdevice . . . 281

Problem:″Routeraddressnotspecifiedornot validforportmethod″errormessage . . . . 282

Problem:OnSolaris,LoadBalancerprocesses endwhenyouexittheterminalwindowfrom whichtheystarted. . . 282

Problem:Settingtheaddressparameteron ″serveradd″commandslowsdownloading largeconfigurations . . . 283

Problem:OnWindows,anIPaddressconflict errormessageappears . . . 283

Problem:Bothprimaryandbackupmachines areactiveinahighavailabilityconfiguration. . 283

Problem:Clientrequestsfailwhenattempting thereturnoflargepageresponses . . . 283

Problem:OnWindowssystems,″Servernot responding″erroroccurswhenissuingdscontrol orlbadmin . . . 284

Problem:HighavailabilityDispatchermachines mayfailtosynchronizeonLinuxforS/390 systemsonqethdrivers . . . 284

Solvingcommonproblems—CBR. . . 284

Problem:CBRwillnotrun . . . 284

Problem:cbrcontrolorlbadmincommandfails 285 Problem:Requestsnotbeingloadbalanced . . 285

(11)

Problem:OnSolaris,cbrcontrolexecutorstart

commandfails . . . 285

Problem:Syntacticalorconfigurationerror . . 285

Problem:OnWindowsplatform,corrupted Latin-1nationalcharactersappearincommand promptwindow . . . 286

Problem:OnWindows,resolvingIPaddressto hostnamewhenmorethanoneaddressis configuredtoanadapter . . . 287

Solvingcommonproblems—SiteSelector . . . . 287

Problem:SiteSelectorwillnotrun . . . 287

Problem:SiteSelectordoesn’tround-robintraffic fromSolarisclients . . . 287

Problem:sscontrolorlbadmincommandfails 287 Problem:Thessserverisfailingtostarton Windowsplatform . . . 288

Problem:SiteSelectorwithduplicateroutesnot loadbalancingcorrectly . . . 288

Solvingcommonproblems—CiscoCSSController 289 Problem:ccoserverwillnotstart . . . 289

Problem:ccocontrolorlbadmincommandfails 289 Problem:Cannotcreateregistryonport13099 290 Problem:OnWindowsplatform,unexpected GUIbehaviorwhenusingMatroxAGPvideo cards . . . 290

Problem:Receivedaconnectionerrorwhen addingaconsultant . . . 290

Problem:Weightsarenotbeingupdatedonthe switch. . . 290

Problem:Refreshcommanddidnotupdatethe consultantconfiguration. . . 291

Solvingcommonproblems—NortelAlteon Controller . . . 291

Problem:nalserverwillnotstart . . . 291

Problem:nalcontrolorlbadmincommandfails 291 Problem:Cannotcreateregistryonport14099 292 Problem:OnWindowsplatform,unexpected GUIbehaviorwhenusingMatroxAGPvideo cards . . . 292

Problem:Receivedaconnectionerrorwhen addingaconsultant . . . 293

Problem:Weightsarenotbeingupdatedonthe switch. . . 293

Problem:Refreshcommanddidnotupdatethe consultantconfiguration. . . 293

Problem:OnWindows,corruptedLatin-1 nationalcharactersappearincommandprompt window . . . 293

Solvingcommonproblems—MetricServer . . . 294

Problem:MetricServerIOExceptionon Windowsplatformrunning.bator.cmduser metricfiles . . . 294

Problem:MetricServernotreportingloadsto LoadBalancermachine . . . 294

Problem:MetricServerlogreports″Signatureis necessaryforaccesstoagent″ . . . 294

Problem:OnAIX,whilerunningMetricServer underheavystress,ps–vgcommandoutput maybecomecorrupted . . . 294

Problem:ConfiguringMetricServerina two-tierconfigurationwithSiteSelector load-balancingacrosshigh-availability Dispatchers . . . 295

Problem:Scripts,runningonmulti-CPUSolaris machines,produceunwantedconsolemessages . 296

Part

9.

Command

Reference

.

. 297

Chapter

26.

How

to

read

a

syntax

diagram

.

. 299

Symbolsandpunctuation . . . 299

Parameters . . . 299

Syntaxexamples . . . 299

Chapter

27.

Command

reference

for

Dispatcher

and

CBR

.

. 301

ConfigurationdifferencesbetweenCBRand Dispatcher . . . 302

dscontroladvisor—controltheadvisor . . . . 303

dscontrolbinlog—controlthebinarylogfile . . 308

dscontrolcluster—configureclusters . . . 309

dscontrolexecutor—controltheexecutor. . . . 313

dscontrolfile—manageconfigurationfiles . . . 317

(12)

dscontrolhelp—displayorprinthelpforthis

command . . . 319

dscontrolhighavailability—controlhigh availability . . . 320

dscontrolhost—configurearemotemachine . . 324

dscontrollogstatus—displayserverlogsettings 325 dscontrolmanager—controlthemanager . . . 326

dscontrolmetric—configuresystemmetrics. . . 331

dscontrolport—configureports. . . 332

dscontrolrule—configurerules . . . 338

dscontrolserver—configureservers . . . 344

dscontrolset—configureserverlog. . . 349

dscontrolstatus—displaywhetherthemanager andadvisorsarerunning . . . 350

dscontrolsubagent—configureSNMPsubagent 351

Chapter

28.

Command

reference

for

Site

Selector

.

. 353

sscontroladvisor—controltheadvisor . . . . 354

sscontrolfile—manageconfigurationfiles . . . 358

sscontrolhelp—displayorprinthelpforthis command . . . 360

sscontrollogstatus—displayserverlogsettings 361 sscontrolmanager—controlthemanager. . . . 362

sscontrolmetric—configuresystemmetrics . . . 366

sscontrolnameserver—controltheNameServer 367 sscontrolrule—configurerules . . . 368

sscontrolserver—configureservers. . . 371

sscontrolset—configureserverlog. . . 373

sscontrolsitename—configureasitename . . . 374

sscontrolstatus—displaywhetherthemanager andadvisorsarerunning . . . 377

Chapter

29.

Command

reference

for

Cisco

CSS

Controller

.

. 379

ccocontrolconsultant—configureandcontrola consultant . . . 380

ccocontrolcontroller—managethecontroller . . 383

ccocontrolfile—manageconfigurationfiles . . . 385

ccocontrolhelp—displayorprinthelpforthis command . . . 386

ccocontrolhighavailability—controlhigh availability . . . 387

ccocontrolmetriccollector—configuremetric collector . . . 390

ccocontrolownercontent—controltheowner nameandcontentrule . . . 392

ccocontrolservice—configureaservice . . . . 395

Chapter

30.

Command

reference

for

Nortel

Alteon

Controller

.

. 397

nalcontrolconsultant—configureandcontrola consultant . . . 398

nalcontrolcontroller—managethecontroller . . 401

nalcontrolfile—manageconfigurationfiles . . . 403

nalcontrolhelp—displayorprinthelpforthis command . . . 404

nalcontrolhighavailability—controlhigh availability . . . 405

nalcontrolmetriccollector—configuremetric collector . . . 408

nalcontrolserver—configureaserver . . . 410

nalcontrolservice—configureaservice . . . . 412

Appendix

A.

GUI:

General

instructions

415

Appendix

B.

Content

rule

(pattern)

syntax

.

. 421

Contentrule(pattern)syntax: . . . 421

Reservedkeywords . . . 421

Appendix

C.

Sample

configuration

files

.

. 425

SampleLoadBalancerconfigurationfiles . . . . 425

DispatcherConfigurationfile—AIX,Linux,and Solaris. . . 425

DispatcherConfigurationfile—Windows . . . 428

Appendix

D.

Sample

of

a

2-tier

high

availability

configuration

using

Dispatcher,

CBR,

and

Caching

Proxy

. 435

Servermachinesetup . . . 435

Appendix

E.

Notices

.

. 439

Trademarks . . . 440

Glossary

.

. 443

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Tables

1. AIXinstallpimages . . . 33

2. AIXinstallcommands . . . 35

3. HP-UXpackageinstallationdetailsforLoad Balancer. . . 37

4. ConfigurationtasksfortheDispatcherfunction 61 5. Commandstoaliastheloopbackdevice(lo0) forDispatcher. . . 69

6. Commandstodeleteanyextraroutefor Dispatcher . . . 72

7. ConfigurationtasksfortheCBRcomponent 97 8. CommandstoaliastheNIC. . . 103

9. ConfigurationtasksfortheSiteSelector component . . . 117

10. ConfigurationtasksfortheCiscoCSS Controllercomponent. . . 135

11. ConfigurationtasksfortheNortelAlteon Controllercomponent. . . 155

12. AdvancedconfigurationtasksforLoad Balancer . . . 163

13. AdvancedconfigurationtasksfortheLoad Balancer . . . 183

14. Dispatchertroubleshootingtable . . . 257

15. CBRTroubleshootingtable . . . 261

16. SiteSelectortroubleshootingtable. . . 262

17. ControllerforCiscoCSSSwitches troubleshootingtable . . . 263

18. NortelAlteonControllertroubleshootingtable 264 19. MetricServertroubleshootingtable . . . . 265

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(15)

Figures

1. Exampleofaphysicalrepresentationofasite

usingDispatchertomanagelocalservers . . 14

2. ExampleofasiteusingDispatcherandMetric

Servertomanageservers . . . 15

3. ExampleofasiteusingDispatchertomanage

localandremoteservers . . . 15

4. ExampleofasiteusingCBRtomanagelocal

servers . . . 17

5. ExampleofasiteusingSiteSelectorand

MetricServertomanagelocalandremote

servers . . . 18

6. ExampleofasiteusingCiscoCSSController

andMetricServertomanagelocalservices . . 20

7. ExampleofasiteusingNortelAlteon

Controllertomanagelocalservers . . . 21

8. AsimplelocalDispatcherconfiguration 45

9. ExampleofDispatcherconfiguredwitha

singleclusterand2ports . . . 48

10. ExampleofDispatcherconfiguredwithtwo

clusters,eachwithoneport . . . 49

11. ExampleofDispatcherconfiguredwith2

clusters,eachwith2ports. . . 50 12. ExampleforusingDispatcher’snatorcbr

forwardingmethods . . . 56

13. ExampleofaDispatcherusingsimplehigh

availability. . . 59 14. ExampleofaDispatcherusingmutualhigh

availability. . . 60 15. ExampleoftheIPaddressesneededforthe

Dispatchermachine. . . 65 16. AsimplelocalCBRconfiguration . . . 87

17. ExampleofCBRconfiguredwithasingle

clusterand2ports . . . 90

18. ExampleofCBRconfiguredwithtwoclusters,

eachwithoneport . . . 91

19. ExampleofCBRconfiguredwith2clusters,

eachwith2ports . . . 92

20. CBRconfigurationfileforAIX,Linux,and

Solaris . . . 102

21. CBRconfigurationfileforHP-UX. . . 102

22. CBRconfigurationfileforWindows . . . . 102

23. AsimpleSiteSelectorconfiguration . . . . 109

24. ExampleofaDNSenvironment . . . 113

25. AsimpleCiscoCSSControllerconfiguration 125

26. Exampleofaconsultantconnectedbehindthe

switches . . . 131

27. Exampleofconsultant(withoptionalhigh

availabilitypartner),configuredbehind

switchwithuserinterfaceinfrontofswitch . 132

28. AsimpleNortelAlteonController

configuration . . . 143

29. Exampleofaconsultantconnectedbehindthe

switch . . . 149

30. Exampleofconsultantconnectedthroughan

intranetinfrontofswitch . . . 149

31. Exampleofconsultantbehindswitchand

userinterfaceinfrontofswitch . . . 150

32. Exampleofconsultantconfiguredwith

backupservers . . . 151

33. ExampleofNortelAlteonControllerand

NortelAlteonWebSwitchhighavailability . 153

34. Exampleofatwo-tieredWANconfiguration

usingtheselfadvisor . . . 174

35. Exampleofaconfigurationconsistingofa

singleLANsegment . . . 207

36. Exampleofconfigurationusinglocaland

remoteservers . . . 207

37. Wideareaexampleconfigurationwithremote

LoadBalancers . . . 210

38. Wideareaexampleconfigurationwithserver

platformthatsupportsGRE. . . 212 39. Exampleofaprivatenetworkusing

Dispatcher . . . 214

40. SNMPcommandsforLinuxandUNIX

systems . . . 244

41. Thegraphicaluserinterface(GUI)displaying

theGUItreestructureexpansionofthe

Dispatchercomponent . . . 415

theGUItreestructureexpansionoftheCBR component . . . 416

theGUItreestructureexpansionoftheSite Selectorcomponent . . . 417

theGUItreestructureexpansionoftheCisco CSSControllercomponent . . . 418

theGUItreestructureexpansionoftheNortel AlteonControllercomponent . . . 419

46. Exampleofa2-tier,highavailability

configurationusingDispatcher,CBR,and

CachingProxy . . . 435

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(17)

About

this

book

Thisbookexplainshowtoplanfor,install,configure,use,andtroubleshootIBM® WebSphere®ApplicationServer LoadBalancerforAIX®,HP-UX,Linux™,Solaris, and Windows®operatingsystems. Previously,thisproductwascalledEdgeServer Network Dispatcher,SecureWay® NetworkDispatcher,eNetworkDispatcher,and InteractiveNetworkDispatcher.

Who

should

read

this

book

TheLoad BalancerAdministrationGuideiswrittenfor experiencednetworkand system administratorswhoarefamiliar withtheiroperatingsystemsandwith providing Internetservices.Prior exposuretoLoadBalancerisnotrequired. Thisbookisnotintended tosupportpreviousreleasesofLoadBalancer.

Reference

Information

TheEdgeComponentsInformationCenterWebsitelinkstothecurrentversionof this bookinHTMLandPDFformats.

For themostcurrentupdatesaboutLoadBalancer,visit theWebsitesupport page and linkto theTechnotesite.

Toaccesstheseand relatedWebpages,go totheURLslistedin“Related documents andWebsites”onpagexvii.

Accessibility

Accessibilityfeatureshelpauser whohasaphysicaldisability,suchasrestricted mobilityorlimited vision,tousesoftwareproductssuccessfully.Thesearethe major accessibilityfeaturesinLoadBalancer:

v Youcanusescreen-readersoftwareanda digitalspeechsynthesizertohearwhat

isdisplayed onthescreen.Youcanalsousevoicerecognitionsoftware,suchas IBMViaVoice®_,_to_enter_data_and _to_navigate_the_user _interface.

v Youcanoperatefeaturesbyusingthekeyboardinsteadofthemouse.

v Youcanconfigureand administerLoadBalancerfeaturesbyusingstandardtext

editorsorcommand-lineinterfaces,insteadoftheprovidedgraphicalinterfaces. Formoreinformationabouttheaccessibilityofparticularfeatures, refertothe documentationaboutthosefeatures.

How

to

send

your

comments

Yourfeedbackisimportantinhelpingtoprovidethemostaccurateand

high-qualityinformation.Ifyouhaveanycommentsaboutthisbookoranyother Edgecomponentsdocument:

v Sendyour [email protected] suretoincludethe

nameofthebook,thepart numberofthebook,theversion,andif applicable thespecific locationofthetextyouarecommentingon(forexample,apage numberortablenumber).

(18)

(19)

and

Web

sites

v Concepts,Planning, andInstallationforEdgeComponentsGC31-6855-02

v ProgrammingGuideforEdgeComponentsGC31-6856-02

v CachingProxyAdministrationGuideGC31-6857-02

v

IBMWebsitehome:www.ibm.com/

v IBMWebSphereApplicationServerproduct:

www.ibm.com/software/webservers/appserv/

v IBMWebSphereApplicationServerlibraryWebsite:

www.ibm.com/software/webservers/appserv/was/library/ v IBMWebSphereApplicationServersupportWebsite:

www.ibm.com/software/webservers/appserv/was/support/ v IBMWebSphereApplicationServerInformationCenter:

www.ibm.com/software/webservers/appserv/infocenter.html

v IBMWebSphereApplicationServerEdgeComponentsInformationCenter:

www.ibm.com/software/webservers/appserv/ecinfocenter.html

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Part

1.

Introducing

Load

Balancer

Thispartprovides anoverviewofLoadBalanceranditscomponents,a high-level descriptionofconfigurationfeaturesthatareavailable,alistof hardwareand software requirements,andinstallationinstructions.Itcontains thefollowing chapters:

v Chapter1,“Overview ofLoadBalancer,”onpage3

v Chapter2,“Overview ofthecomponentsof LoadBalancer,”onpage13

v Chapter3,“Managingyour network:Determining whichLoadBalancerfeatures

touse,”onpage23

v Chapter4,“InstallingLoadBalancer,”onpage33

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Chapter

1.

Overview

of

Load

Balancer

Thischaptergivesan overviewofLoadBalancerandincludesthefollowing sections:

v “WhatisLoadBalancer?”

v

“Whichcomponent(s)of LoadBalancercanIuse?”

v “Whataretheadvantages tousingLoadBalancer?”onpage4

v “Howabouthighavailability?”onpage5

v “Newfeatures”onpage6

For ahigh-levellistofconfigurationfeaturesprovidedbyeachoftheLoad

Balancercomponents,toassistyouinplanningwhichfeaturestouseformanaging your network,seeChapter3, “Managingyournetwork:Determining whichLoad Balancerfeaturestouse,”onpage23.

What

is

Load

Balancer?

LoadBalancerisasoftware solutionfordistributingincoming clientrequests acrossservers.Itbooststheperformanceofservers bydirectingTCP/IPsession requeststodifferentserverswithin agroup ofservers;inthisway,it balancesthe requestsamongalltheservers.Thisloadbalancingistransparenttousersand otherapplications.LoadBalancerisusefulforapplicationssuchase-mailservers, World WideWebservers,distributed paralleldatabasequeries,and otherTCP/IP applications.

WhenusedwithWebservers,LoadBalancercanhelpmaximizethepotentialof your sitebyprovidinga powerful,flexible,andscalablesolutiontopeak-demand problems.Ifvisitorstoyour sitecan’tget throughattimesofgreatestdemand,use LoadBalancertoautomaticallyfindtheoptimalservertohandleincoming

requests,thusenhancingyourcustomers’satisfactionandyourprofitability.

Which

component(s)

of

Load

Balancer

can

I

use?

IMPORTANT:IfyouareusingLoadBalancerfor IPv6,onlytheDispatcher

componentisavailable.SeeChapter8,“DeployingDispatcheronLoadBalancerfor IPv6,” onpage77formore information.

LoadBalancerconsistsofthefollowingfivecomponentsthatcanbeused separately ortogethertoprovidesuperiorload-balancingresults:

v YoucanusetheDispatchercomponentbyitselftobalancetheload onservers

withina localareanetworkorwideareanetworkusinga numberofweights andmeasurementsthatare dynamicallysetbyDispatcher.Thiscomponent providesloadbalancingat alevelofspecificservices,suchasHTTP,FTP,SSL, NNTP,IMAP,POP3,SMTP,and Telnet.Itdoesnotusea domainnameserverto mapdomainnamestoIPaddresses.

ForHTTPprotocol,youcanalsousetheDispatcher’scontent-basedrouting featuretoloadbalancebased onthecontentof theclientrequest. Thechosen serveristheresultof matchingtheURLtoaspecifiedrule. Dispatcher’s content-basedrouting(cbrforwardingmethod) doesnotrequire CachingProxy. v ForbothHTTPandHTTPS(SSL)protocol,youcanusetheContentBased

Routing(CBR)componenttoloadbalancebasedonthecontentoftheclient

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request.Aclientsendsa requesttoCachingProxy,andCachingProxysendsthe requesttotheappropriateserver.Thechosenserveristheresultofmatching the URLtoaspecified rule.

Note: TheContentBased Routing(CBR)componentisavailableonall

supportedplatformsexceptthoserunninga64-bitJVM.Alternatively,you canusethecbrforwardingmethod ofLoadBalancer’sDispatcher

componenttoprovidecontent-basedroutingwithouttheuseofCaching Proxy.See“Dispatcher’scontent-basedrouting(cbrforwardingmethod)” onpage54formoreinformation.

v YoucanusetheSiteSelectorcomponenttobalancetheloadonserverswithina

localorwideareanetworkusingaDNSround-robinapproachora more advanceduser-specifiedapproach.SiteSelectorworks inconjunctionwith a nameservertomapDNSnamestoIPaddresses.

v YoucanusetheCiscoCSSControllerortheNortel AlteonController

componenttogenerateserverweightsthatare thensenttotheCiscoCSSSwitch ortheNortelAlteonWebSwitchrespectivelyforoptimal serverselection,load optimization,and faulttolerance.

For moreinformationontheDispatcher,CBR, SiteSelector,CiscoCSSController, and NortelAlteonControllercomponents,see“WhatarethecomponentsofLoad Balancer?”onpage13.

What

are

the

advantages

to

using

Load

Balancer?

The numberofusersandnetworksconnectedtotheglobalInternetisgrowing exponentially. Thisgrowthiscausingproblemsof scalethatcanlimitusers’access topopularsites.

Currently,networkadministratorsareusingnumerousmethodstotrytomaximize access. Someofthese methodsallowuserstochoosea differentserverat randomif an earlierchoiceisslow ornotresponding.Thisapproachiscumbersome,

annoying,andinefficient.Anothermethodisstandardround-robin,inwhichthe domain nameserverselectsserversinturntohandlerequests.Thisapproachis better,but stillinefficientbecauseitblindlyforwardstrafficwithoutany

consideration oftheserverworkload.Inaddition,evenif aserverfails,requests continuetobe senttoit.

The needforamorepowerfulsolutionhasresultedinLoadBalancer.Itoffers numerous benefitsoverearlier andcompetingsolutions:

Scalability

Asthenumberofclient requestsincreases,youcanaddservers

dynamically, providingsupportfortensof millionsof requestsper day,on tensor evenhundredsofservers.

Efficientuseof equipment

Loadbalancing ensuresthateachgroupofservers makesoptimumuseof itshardwarebyminimizingthehot-spots thatfrequentlyoccurwith a standardround-robinmethod.

Easyintegration

LoadBalancerusesstandardTCP/IPorUDP/IPprotocols.Youcanaddit toyour existingnetworkwithoutmakinganyphysicalchangestothe network. Itissimple toinstalland configure.

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Lowoverhead

Using simplemaclevelforwardingmethod,theDispatchercomponent onlylooksat theinbound client-to-serverflows.Itdoesnotneedto seethe outbound server-to-clientflows.Thissignificantlyreducesitsimpactonthe application comparedwith otherapproachesandcanresult inimproved networkperformance.

Highavailability

TheDispatcher,CiscoCSSController,andNortelAlteonController

componentsofferbuilt-inhighavailability,utilizinga backupmachinethat remainsreadyatalltimestotakeoverloadbalancingshouldtheprimary servermachine fail.Whenoneoftheserversfails,requestscontinuetobe servicedbytheotherserver.Thiseliminatesanyserverasa singlepointof failureand makesthesitehighlyavailable.

For moreinformation,see“Howabouthighavailability?”

Content-basedrouting(usingtheCBRcomponent orDispatchercomponent)

InconjunctionwithCachingProxy,theCBRcomponenthastheabilityto proxyHTTPandHTTPS(SSL)requeststo specificserversbased onthe contentrequested.For example,if arequestcontainsthestring″/cgi-bin/″ inthedirectoryportion oftheURL,andtheservernameisa localserver, CBRcandirecttherequesttothebestserverina setofservers specifically allocatedtohandlecgirequests.

Note: TheContentBasedRouting (CBR)componentisavailableonall

supportedplatforms exceptthose runninga 64-bitJVM. Alternatively,youcanusethecbrforwardingmethodof Load Balancer’sDispatchercomponenttoprovidecontent-basedrouting withouttheuseofCachingProxy.See “Dispatcher’scontent-based routing(cbrforwardingmethod)”onpage54formore information. TheDispatchercomponentalsoprovides content-basedrouting,butitdoes notrequiretheCachingProxytobeinstalled.BecausetheDispatcher component’scontent-basedroutingisperformedin thekernelaspackets are received,itcanprovidefastercontent-basedroutingthantheCBR component. TheDispatchercomponentperformscontent-basedroutingfor HTTP(usingthe″content″typerule)and HTTPS(usingSSLsession ID affinity).

Note: OnlytheCBRcomponentcanusethecontentrule forHTTPS(SSL)

whenload-balancingtrafficbased uponthecontentof theHTTP request,whichrequiresdecryptingandre-encryptingmessages.

How

about

high

availability?

Dispatcher

TheDispatcher componentoffersa built-inhighavailabilityfeature,eliminating Dispatcherasa singlepointoffailurefromyour network.Thisfeatureinvolvesthe useofa secondDispatchermachinethatmonitorsthemain,orprimary,machine and standsbytotakeoverthetaskofloadbalancingshouldtheprimarymachine fail atanytime. TheDispatchercomponentalsooffersmutualhighavailability whichallowstwomachinestobebothprimaryand secondary(backup)foreach other. See“Configure highavailability”onpage186.

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CBR

or

Site

Selector

Whenusingatwo-tierconfigurationwitha Dispatchermachineloadbalancing trafficacrossmultipleservers thathaveeither CBRorSite Selector,youcanachieve a levelof highavailabilityforthesecomponentsofLoadBalancer.

Note: Forconfigurationswhichload-balance acrossmultipleservers thatcontain

SiteSelector,onlyusea DispatchermachinethatisrunningonAIX, HP-UX, Solaris,orWindows system.ThehighavailabilitysolutionforSiteSelector doesnotworkonLinuxdue toDispatcheradvisorstargetingtheserverIP address.SiteSelectorrespondsusingitsprimaryIPaddress(asopposedto theclusteraddress),causingtheDNSrequestfromtherequestorto fail.

Cisco

CSS

Controller

or

Nortel

Alteon

Controller

The controllershaveahighavailabilityfeature toeliminatethecontrollerasa single pointoffailure.Acontrollerononemachinemaybe configuredasa primary andacontrollerona differentmachinemaybeconfiguredasa backup. The backupmonitorstheprimaryandstandsbytotakeoverthetaskofproviding serverweights totheswitchesshouldtheprimaryfail.See“Highavailability”on page219 formoreinformation.

New

features

Load BalancerforIBMWebSphereApplicationServerVersion 6.0.2includesall thenew featuresand correctiveupdatesfromearlierV5and V6releases.

New

features

for

6.0.2

Load BalancerforIBMWebSphereApplicationServerVersion 6.0.2containsa number ofnewfeatures. Themostsignificantnew featuresare listedhere. v SupportforIPv6addressing

LoadBalancerfor IPv6isnow available.TheLoadBalancerforIPv6installation containsonlytheDispatchercomponentbutcansupportbothIPv4and the extendedIPaddressingschemeof IPv6.

TheoriginalLoadBalancer(whichsupportsIPv4only)isstillavailable forv6.0.2 withfullfunctionalityofallcomponents.

ForinformationonthelimitationsandconfigurationdifferencesofDispatcheron LoadBalancerfor IPv6,seeChapter8, “DeployingDispatcheronLoadBalancer forIPv6,”onpage77.

v Newconfigurablesetting—maximumsegmentsize

Thisfeature appliestoDispatcher’snatorcbrforwardingmethod.

Themaximumsegmentsize(mss)isanewconfigurable settingfor theexecutor command.

Formoreinformation,see“dscontrolexecutor—controltheexecutor”onpage 313.

v Additionalplatformsupport

Forinformationonsupportedhardwareand softwaresystems,refertothe followingWebpage,

http://www.ibm.com/software/webservers/appserv/doc/latest/prereq.html.

New

features

for

6.0.1

Load BalancerforIBMWebSphereApplicationServerVersion 6.0.1containsa number ofnewfeatures. Themostsignificantnew featuresare listedhere.

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v Supportforplatformsrunning64-bit JVM

Thisfeature appliestoalltheLoadBalancercomponents,excepttheCBR component.

LoadBalancerisnowavailable onplatformsrunninga64-bit JVM.For

informationonsupportedhardwareandsoftwaresystems, referto thefollowing Webpage,

http://www.ibm.com/software/webservers/appserv/doc/latest/prereq.html. LoadBalancer’sCBRcomponentisnotavailableonplatformsrunninga64-bit JVM.

v Java2SDKautomatically install

Thisfeature appliestoalltheLoadBalancercomponents.

TheJava2 SDKautomaticallyinstallswith LoadBalanceronall platforms. v DefaultadaptertypeforSolaris

ThedefaultadaptertypeforSolaris isnow eriasspecifiedintheibmlb.conf file.Itwaspreviouslyspecifiedashme.

New

features

for

6.0

Load BalancerforIBMWebSphereApplicationServerVersion 6.0containsa number ofnewfeatures. Themostsignificantnew featuresare listedhere. v OnWindowssystems,collocationsupporton Dispatcher’smac forwarding

method

Thisfeature appliestotheDispatchercomponent.

OnWindowssystems, collocationisnow supportedonDispatcher’smac forwardingmethod,inadditiontocollocationoncbrandnatforwarding.See “Usingcollocatedservers”onpage184 formoreinformation.

v OnWindows systems,theexecutorstopcommand isnowsupported

StoppingtheexecutorusingthecommandlineisnowsupportedonWindows systems.

v

Controllingcleanupof connectionrecordsusingfintimeout andstaletimeout

Anew algorithmhasbeendevelopedfortheDispatchercomponenttoimprove theperformance ofconnectionrecordallocationandreuse.Dispatchernolonger usesa separatesystem timerthreadtocleanup staleconnectionrecordsand thereforenolongerneedsthedscontrolexecutorsetfincount command.This commandhasbeendeprecatedand removedfromtheproduct. See“Using fintimeoutand staletimeouttocontrolcleanup ofconnectionrecords”onpage 242formoreinformation.

IMPORTANT:Ensureyouupdateallyourpreviousscriptfiles toreplacetheuse oftheexecutor setfincountcommand.

v OnWindowssystems,dsconfig(ndconfig) commandhasbeenremoved

Theuseofthedsconfig(ndconfig)commandhasbeendeprecated forIPv4 addresses.Toreplace it,usethedscontrolexecutorconfigure command.

IMPORTANT:Ensureyouupdateallyourpreviousscriptfiles toreplacetheuse ofthedsconfig(ndconfig)command.

v Usedscontrol(not ndcontrol)when issuingcommand statementstoconfigure

Dispatcher

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Theuseofdscontrolreplacesndcontrol incommandstatementstoconfigurethe Dispatchercomponent.Useofndcontrol hasbeen deprecated.(Previousreleases supportedtheuseofbothdscontrolorndcontrolinterchangeably.)

Forexample:dscontrolexecutorstart(not, ndcontrolexecutorstart).

IMPORTANT:Ensureyouupdateallyourpreviousscriptfiles tousedscontrol insteadofndcontrol.

v

Supportfor1.4.2versionof32-bitSDK

ForinformationontheSDKsoftwarerequirementforv6.0 EdgeComponents, refertothefollowingWebpage,

http://www.ibm.com/software/webservers/appserv/doc/latest/prereq.html. v Supporton AIX5.3

New

features

for

5.1.1

Load BalancerforIBMWebSphereApplicationServerVersion 5.1.1containsa number ofnewfeatures. Themostsignificantnew featureislistedhere.

v OnLinuxandUNIXsystems,Mozillabrowseristhedefaultbrowserfor

viewinghelps

OnLinuxandUNIXsystems: Forviewinghelps,thedefaultbrowserisMozilla. Forinformationonsupportedbrowserversions, refertothefollowingWebpage: http://www.ibm.com/software/webservers/appserv/doc/latest/prereq.html

New

features

for

5.1

Load BalancerforIBMWebSphereApplicationServerVersion 5.1containsa number ofnewfeatures. Themostsignificantnew featureislistedhere. v SupportforFTP portandwildcardport onthesamecluster

Thisfeature appliestotheDispatchercomponents.

Withthisenhancement,thereisnowsupportforconfiguringbothanFTPport andwildcardportonthesamecluster.See“Usewildcardporttodirect

unconfiguredporttraffic” onpage215and “WildcardporttohandleFTPtraffic” onpage216 formoreinformation.

New

features

for

5.0.2

Load BalancerforIBMWebSphereApplicationServerVersion 5.0.2containsa number ofnewfeatures. Themostsignificantnew featuresare listedhere. v

Supporton LinuxforS/390

®_zSeries®_,_iSeries™_,_and_pSeries® Thisfeature appliestoalltheLoadBalancercomponents.

Inaddition tosupportforrunningLoadBalanceronLinuxforIntel™_,_Load

BalancernowrunsonLinuxforS/390zSeries,iSeriesandpSeries. Forsupportedplatforms,refertothefollowingWebpage,

http://www.ibm.com/software/webservers/appserv/doc/latest/prereq.html. v Supporton Solaris9

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http://www.ibm.com/software/webservers/appserv/doc/latest/prereq.html. v Supporton WindowsServer2003

Inaddition toWindows2000,LoadBalancernow runsonWindowsServer2003. Forinformationonsupportedhardwareand softwaresystems,refertothe followingWebpage,

New

features

for

5.0.1

Load BalancerforIBMWebSphereApplicationServerVersion 5.0.1containsa number ofnewfeatures. Themostsignificantnew featuresare listedhere. v Supporton HP-UXVersion11i

Inaddition tosupportforAIX, Linux,Solaris,andWindowssystems, Load BalancernowrunsonHP-UX.

http://www.ibm.com/software/webservers/appserv/doc/latest/prereq.html. v Supporton AIX5.2

New

features

for

5.0

Load BalancerforIBMWebSphereApplicationServerVersion 5.0containsa number ofnewfeatures. Themostsignificantare listedhere.

v

EnhancementtotheCiscoCSSControllercomponent

TheCiscoCSSController(formerlyknownasCiscoConsultant) isa Load Balancercomponentthatcalculatesweights forserversbeingloadbalancedby theCiscoCSS switch.TheCiscoCSSswitch isa hardwarebasedloadbalancer thatsupportsSNMP.The controllerenhancestheserverload-balancing function oftheCisco CSSswitchwith greaterapplication andsystemawareness.

SeeChapter15,“Quickstartconfiguration,”onpage125,Chapter16,“Planning forCiscoCSSController,”onpage129,and Chapter17,“ConfiguringCiscoCSS Controller,”onpage135formoreinformation.

v NortelAlteonControllercomponent

Thisfeature isa newcomponentforLoadBalancer.

TheNortelAlteonControllercalculatesweights forserversbeingloadbalanced bya NortelAlteonWebSwitch.TheNortelAlteonWebSwitchisahardware basedloadbalancerwith anSNMPinterfaceforfetchingconnectioninformation andsettingweights.TheNortelAlteonControllerisanewLoadBalancer componentwhichmonitorsserversbeingloadbalancedbytheAlteonswitch andprovidesappropriateweights toensureaccurateloadbalancing.The controllerenhancestheserverload-balancing functionoftheNortelAlteon switchwithgreaterapplicationand systemawareness.

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SeeChapter18,“Quickstartconfiguration,”onpage143,Chapter19,“Planning forNortelAlteonController,”onpage147,andChapter20,“ConfiguringNortel AlteonController,”onpage155formoreinformation.

v Controllerhighavailabilitysupport

Thisfeature appliestotheCiscoCSSControllerand NortelAlteonController components.

LoadBalancernow supportshigh availabilityforboththeCiscoCSSController componentand theNortelAlteonControllercomponent.Thecustomercannow installa controllerona backupservertotakeoveriftheprimarycontrollerfails. ForCiscoCSSController,see“Highavailability”onpage132formore

information.

ForNortelAlteonController,see“Highavailability”onpage152 formore information.

v Connectionsper secondruleenhancement

Thisfeature appliestotheDispatcherandCBRcomponents.

Theenhancementtotheconnectionspersecondruleallowsthecustomerto specifythe″upserversonrule″option.By specifyingthisoption,youcanensure thattheremainingservers willnotbeoverloadedif oneormoreserversinthe serversetgoesdown.

See“Usingrulesbased ontheconnectionspersecond”onpage194 formore information.

v CBRactivecookieaffinityenhancement

Thisfeature appliestotheCBRcomponent.

Thepreviousimplementationof CBRactivecookieaffinitybasedclient

connectionstoa serveronthecluster andportoftherequest.Thiscanbecomea problemin configurationswherethereare multipleruleswithdifferentserver sets.Theenhancementwillallowformultipleaffinities withina singlecluster andport,allowingaclienttomaintain affinitywith potentiallymanydifferent serversbasedonthecontextoftherequest.

See“Activecookieaffinity” onpage203 formoreinformation. v

LinuxSNMPsupport

LoadBalancernow providesSNMPsupport onLinuxplatforms.See “SNMP commandsandprotocol”onpage243 formoreinformation.

v RemoteWeb-basedadministration support

Thisfeature appliestoallthecomponentsofLoadBalancer.

LoadBalancernow supportsRemoteWeb-basedadministrationin additionto remoteadministrationviaRMI(remote methodinvocation).Web-based administrationprovidessecure,authenticatedremoteadministrationof Load Balancer,evenwhenaa firewallispresent.See“Web-basedadministration”on page237formoreinformation.

v Supportforcommand lineaccessfromtheGUI

Thisfeature appliestoallthecomponentsofLoadBalancer.

Acommandline(″Sendcommand″)cannowbe accessedfromtheHostnode in theGUItree.Seepage419 formoreinformation.

v Newproblemdetermination tool(lbpd)

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ForLoadBalancerproblemdetermination,atool(lbpd)hasbeen providedthat willquickly andeasilygatherimportantinformationthatthecustomercansend toIBMservice.See“Gatheringtroubleshooting information”onpage253for moreinformation.

v ″Heavyweight″HTTPSadvisorprovided

Thisfeature appliestotheDispatcher,CBR,andSite Selectorcomponents. Inaddition tothe″lightweight″SSLadvisor,LoadBalancernowprovidesa

″heavyweight″HTTPSadvisor.TheHTTPSadvisoropensfullSSLconnections whichestablishesafullSSLsocketwiththeserver.(Incontrast,thelightweight SSLadvisordoesnotestablisha fullSSLsocketwith theserver.)

See“Listofadvisors”onpage171formoreinformationontheHTTPSadvisor. v LDAPadvisorprovided

LoadBalancernow providesanLDAPadvisorthatmonitorsthehealthofLDAP servers.

See“Listofadvisors”onpage171formoreinformation. v Advisorretry connections

Advisorsnowhavetheabilitytoretryconnectionsbefore markinga serveras down.

See“Advisorretry” onpage171and“Advisorretry”onpage225formore information.

v SendingTCPresetswhenserverisdown

Dispatchernowhastheabilitytosend aTCPresettoadownserver.ATCP resetcausestheconnectiontobeimmediatelyclosed.

See“SendingTCPresettoa downserver(Dispatchercomponentonly)”onpage 166formoreinformation.

v FeaturesremovedfromtheLoadBalanceroffering

ThefollowingfeatureshavebeenremovedfromLoadBalancer – MailboxLocatorcomponent

– Server DirectedAffinity(SDA)

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Chapter

2.

Overview

of

the

components

of

Load

Balancer

Thischaptergivesan overviewofLoadBalancercomponentsandincludesthe followingsections:

v “WhatarethecomponentsofLoadBalancer?”

v

“OverviewoftheDispatchercomponent”

v “OverviewoftheContentBasedRouting (CBR)component”onpage16

v “OverviewoftheSiteSelectorcomponent”onpage17

v “OverviewoftheCiscoCSSControllercomponent”onpage18

v “OverviewofNortelAlteonControllercomponent”onpage20

For ahigh-levellistofconfigurationfeaturesprovidedbyeachoftheLoad

Balancercomponents,toassistyouinplanningwhichfeaturestouseformanaging your network,seeChapter3, “Managingyournetwork:Determining whichLoad Balancerfeaturestouse,”onpage23.

What

are

the

components

of

Load

Balancer?

Thefivecomponentsof LoadBalancerare:Dispatcher,ContentBasedRouting (CBR), SiteSelector,CiscoCSSController,andNortelAlteonController.Load Balancergivesyoutheflexibilityofusingthecomponentsseparatelyortogether dependingonyoursiteconfiguration. Thissectiongivesanoverviewof these components.

IMPORTANT:IfyouareusingLoadBalancerfor IPv6,onlytheDispatcher

componentisavailable.SeeChapter8,“DeployingDispatcheronLoadBalancerfor IPv6,” onpage77formore information.

Overview

of

the

Dispatcher

component

TheDispatcher componentbalances trafficamongyour serversthrough aunique combinationof loadbalancingandmanagement software.Dispatchercanalso detecta failedserverand forwardtrafficaroundit.DispatchersupportsHTTP,FTP, SSL,SMTP,NNTP,IMAP,POP3,Telnet,and anyotherTCPorstatelessUDPbased application.

All clientrequestssenttotheDispatchermachinearedirectedtothe″best″server according toweightsthataresetdynamically. Youcanusethedefault valuesfor those weightsorchangethevaluesduringtheconfigurationprocess.

Dispatcheroffers threeforwarding methods(specifiedontheport): v

MACforwardingmethod(mac).Withthisforwardingmethod,Dispatcherload

balancestheincomingrequesttotheserver.Thes