Extreme Networks Px Series manual Configuring Server Groups

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answer requests. Servers can share an IP address, but the port must be unique for each server.

•Max-connections represents the maximum number of concurrent connections this server can handle. After that number is reached, no more connections are sent to that particular server until some of the open ones have been closed (unless a persistence method is specified; see “Persistence Modes” on page 6-2). Most servers can handle fewer than 5,000 connections.

•Weight is used by weighted algorithms for load balancing. Use equal weights for all servers (or 1 for simplicity’s sake) with non-weighted algorithms. See Chapter 6.

If servers are configured at contiguous IP addresses, and have identical attributes, you can specify many identical servers at once using a range of IP addresses. The specified index is used for the first server and incremented for each configured server. The following example creates servers with indexes 3 through 10:

config server index 3 ipaddress 10.2.2.2 - 10.2.2.9 port 80

max-connections 4000 weight 1

To remove a server or range of servers from the system, use the following commands:


unconfig	server	index	<index>
unconfig	server index		<index> - <index2>
unconfig	server	ipaddress		<ipaddress>
unconfig	server	ipaddress		<ipaddress> - <ipaddress>

Configuring Server Groups

After all of the servers needed for a particular virtual service have been created, they must be organized into a server group. This group is used in the definition of the virtual service itself. The following command creates a server group:

config server-group name <string> policy [rr wrr lc wlc]

Each server group definition includes a unique name, used when configuring the server group or used elsewhere in the configuration. A load balancing policy is the method of choosing servers. See Chapter 6 for policy details.

You can optionally specify a server of last resort for the group. This is a server to which traffic is sent if all the servers in a server-group are down. It could be a server that simply replies to the client with a "SYSTEM DOWN" message, or a server that can service the request under emergency circumstances (perhaps a development machine or

5-2	Px Series Application Switch Installation and Configuration Guide

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Contents Published April Part number 100101-00 Rev Page Contents Installing the PxM Application Switch Module Configuring Servers and Services Index Index of Commands Preface IntroductionConventions Text ConventionsIcon Alerts you to Convention DescriptionRelated Publications Preface Server Load Balancing Concepts Purpose of Server Load BalancingTerms 1Conceptual view of server load balancingLoad Balancing Modes Layer 4 Load BalancingLayer 7 Load Balancing and Content Analysis 2Single client-server transaction using layer3Establishing a layer 7 request Getting Started on Load Balancing Configuration Port RewriteGetting Started on Load Balancing Configuration Page Overview of the SummitPx1 Application Switch Installing the SummitPx1 Application SwitchSummitPx1 Front View 1Px series application switch LEDs Color IndicatesSummitPx1 Application Switch Rear View Signal Description2DB-9 Adapter Pinouts To DB-9Determining the Location Installing the SummitPx1 Application SwitchRack Mounting Powering On the SummitPx1 Free-StandingSetting Up Console Communication Configuring Switch IP Parameters Configuring the 10/100 Ethernet Management Port Installing the PxM Application Switch Module Installing I/O ModulesRemoving I/O Modules Removing I/O Modules Page Managing the Switch Using the Command-Line Interface Abbreviated Syntax and Command CompletionSyntax Symbols 1Command Syntax SymbolsSymbol Description Line-Editing KeysSpecifying Text Values 2Line-Editing KeysCommand History Configuring Management AccessPrompt Text Changing the Default Passwords Creating Accounts Modifying AccountsCommand Description Managing the PxMConfiguring VLANs Configuring Snmp 4SNMP Configuration SettingsSetting Description System ContactConfiguring DNS Client Services SettingDescriptionUsing Secure Shell 2 SSH2 5DNS Client Configuration CommandsEnabling SSH2 for Inbound Switch Access Config ssh2 keyUsing SCP2 from an External SSH2 Client SSH2 Client Functions on the Switch Showing CPU Load UtilitiesChecking Basic Connectivity Logging Configuring a Startup Banner Message Starting the GlobalPx Content Director AgentExample Configuration Internet DNS serverFollowing commands configure all system-related facilities Page Configuring Servers and Services Configuring Real ServersConfiguring Server Groups Configuring Virtual Services Layer 7 Virtual Services Layer 4 Port-based Load BalancingConfiguring Traffic Tagging 1Tag Specifications Configuration ExampleTag Specification Description Tag Range Configuration Example Page Choosing Policies, Persistence Modes, and NAT Scheduling Policies1Scheduling Policies Persistence ModesSpecifier Policy Description Client IP Persistence Mode UDP Flow Persistence1Client IP persistence mode Configuring Client IP Stickiness Cookie Persistence Modes2Self-identifying cookie persistence mode Persistence Modes Hashed Cookie Persistence Session Learned Cookie Persistence Mode 4Learned cookie persistence mode Configuring Cookie Stickiness SSL Session Identifier Persistence Full-NAT Mode NAT ModesServer-only Half-NAT Mode Configuring Full-NAT Mode and Proxy IP AddressesConfiguring Half-NAT Mode Config source-flow name next-hop gateway-mode ip Real Syslog server SummitPx1 Configuration Example Page URL Switching Domain and URL SwitchingDomain Switching 1Typical switching scenario2Domain switching example Configuring URL Switching URL Switching3Simple URL switching example 4More Complicated URL switching example 5Hierarchical approach to pattern rules 1Wildcard Combinations Creating Domain and URL Switching RulesWildcard Example Definition Modifying Existing URL Rules and Domains Application Servers Management net Configuration Example Page Configuring Redundancy Using Vrrp with the SummitPx1Adding and Configuring VRRPs Give backup systems lower prioritiesUsing Vrrp in Existing Redundant Networks 1Application switch using multiple VLANs Vrrp Automatic SynchronizationFollowing commands can be passed from master to backup Configuring Redundancy for the PxM Using Esrp with the PxMConfiguring the PxM for Multiple VLANs For SW2Configuring a Default Gateway Health Checks OverviewServer Startup Pacing Health Checking Procedure Timers and Counters Configuring Health ChecksTypes of Health Checks You can disable health checks for a server group Page 1Statistics Display Commands Monitoring the SwitchShowing Traffic Statistics Displays packet-level counters for Showing Configuration Details 2Configuration Display CommandsConfiguration Displays Status Displays SummitPx128 # show server detailsShow health Information Column DescriptionManaging and Troubleshooting Operation 5Management and Troubleshooting CommandsCommandDescription Index EsrpHttp GET AUX Page Index of Commands