CSS Getting Started Guide (Software Version 7.40) - Configuring Sticky Cookies [Cisco CSS 11500 Series Content Services Switches]

Table Of Contents

Configuring Sticky Cookies

Sticky Overview

Advanced Load-Balancing Method Using Cookies

Sticky Based on a Configured String in an HTTP Cookie Header

Sticky Based on a Cookie in a URL

Sticky Based on a Cookie in the HTTP Header or URL

Where to Go Next

Configuring Sticky Cookies

This chapter provides information on CSS sticky using cookies.

•Sticky Overview

•Advanced Load-Balancing Method Using Cookies

For detailed information on services, sticky parameters and their uses, and Layer 3, Layer 4, and Layer 5 sticky, refer to the Cisco Content Services Switch Content Load-Balancing Configuration Guide.

Sticky Overview

When customers visit an e-commerce site, they usually start out by browsing the site, the Internet equivalent of window shopping. Depending on the application, the site may require that the customer become "stuck" to one server once the connection is established, or the application may not require this until the customer starts to build a shopping cart.

In either case, once the customer adds items to the shopping cart, it is important that all of the customer's requests get directed to the same server so that all the items are contained in one shopping cart on one server. An instance of a customer's shopping cart is typically local to a particular Web server and is not duplicated across multiple servers.

Stickiness is the association between a client and a server that the CSS maintains during a session. Stickiness enables transactions over the Web because the client must remain on the same server for the entire session. Depending on the content rule, the CSS "sticks" a client to an appropriate server after the CSS has determined which load-balancing method to use.

If the CSS determines that a client is already stuck to a particular service, then the CSS places the client request on that service, regardless of the load balancing criteria specified by the matched content rule. If the CSS determines that the client is not stuck to a particular service, it applies normal load balancing to the content request.

Client cookies uniquely identify clients to the services providing content. A cookie is a small data structure used by a server to deliver data to a Web client and request that the client store the information. In certain applications, the client returns the information to the server to maintain the state between the client and the server.

When the CSS examines a request for content and determines through content rule matching that the content is sticky, it examines any cookie or URL present in the content request. The CSS uses this information to place the content request on the appropriate server.

Advanced Load-Balancing Method Using Cookies

A content rule is "sticky" when additional sessions from the same user or client are sent to the same service as the first connection, overriding normal load balancing. By default, the advanced balancing method is disabled.

Use the advanced-balance command to specify an advanced load-balancing method for a content rule that includes stickiness. The advanced-balance command options (cookies, cookieurl, and url) use strings for sticking clients to servers. These options are beneficial when the sticky table limit is too small for your application requirements because the string methods do not use the sticky table.

The following sections provide configuration information for:

•Sticky Based on a Configured String in an HTTP Cookie Header, using the advance-balanced cookies command

•Sticky Based on a Cookie in a URL, using the advance-balanced url command

•Sticky Based on a Cookie in the HTTP Header or URL, using the advance-balanced cookieurl command

For information on additional advanced load-balancing methods including arrowpoint cookies, refer to the Cisco Content Services Switch Content Load-Balancing Configuration Guide.

Sticky Based on a Configured String in an HTTP Cookie Header

If the server returns a cookie that is static and uniquely identifies itself, use the advanced-balance cookies command. This command enables the content rule to stick a client to a server based on the configured string found in the HTTP cookie header. A content rule with a sticky configuration set to advanced-balance cookies requires all clients to enable cookies on their browser.

In the following configuration, the CSS looks for the cookie in the Cookie: field of the HTTP header:

1. The CSS looks for the configured string prefix, which is the cookie name. In this example, the string prefix in the content rule is MyCookie=.

2. If the CSS finds the prefix, then it looks for the value that matches one of the string values configured in one of the services. For example, the string value for service test 1 is server1. The CSS begins searching for the prefix and value at the beginning of the cookie field in the header and searches the entire field until the end of the field.

If the HTTP header spans multiple packets, the CSS searches up to 5 packets by default; however, you can configure the CSS to search up to 20 packets (refer to the global spanning-packets command for more details).

3. If the CSS cannot find the string prefix or match the cookie value with one of the service string values, then the CSS load balances the request according to the configured balance method (roundrobin by default). For more details on what action the CSS takes when it cannot locate the cookie header or the specified cookie string, see the content rule mode sticky-no-cookie-found-action command.
configure
!*************************** GLOBAL ***************************
  ip route 0.0.0.0 0.0.0.0 10.86.191.174 1 
!************************* INTERFACE *************************
interface  3/2
  bridge vlan 2 
!************************** CIRCUIT **************************
circuit VLAN1
  description "client vlan" 
  ip address 10.86.191.161 255.255.255.240 
circuit VLAN2
  description "server vlan" 
  ip address 10.1.1.254 255.255.0.0 
!The string value configured in the service must match the value of 
the cookie for a particular server.
!************************** SERVICE **************************
service test1 
  ip address 10.1.1.1 
  string server1 
  active 
service test2 
  ip address 10.1.1.2 
  string server2 
  active 
service test3 
  ip address 10.1.1.3 
  string server3 
  active 
service test4 
  ip address 10.1.1.4 
  string server4 
  active 
!The string prefix must match the cookie name.  We recommend that you 
include the `=' as part of the string prefix.
!*************************** OWNER ***************************
owner test 
  content stickyCookie 
    advanced-balance cookies 
    string prefix "MyCookie=" 
    add service test1 
    add service test2 
    add service test3 
    add service test4 
    port 80 
    protocol tcp 
active
Sticky Based on a Cookie in a URL

If the cookie is present in the URL instead of the cookie field of the HTTP header, use the advanced-balance url command. Some client applications do not accept cookies. When a site depends upon the information in the cookie, administrators sometimes modify the server application so that it appends the cookie data to the parameters section of the URL. The parameters typically follow a "?" at the end of the main data section of the URL.

In this configuration, the CSS functions in a similar manner as when using the advanced-balance cookies command; however, the CSS looks in the URL after the `?' for the cookie.

Using the full configuration of the "Sticky Based on a Configured String in an HTTP Cookie Header" section, the only difference is the advanced-balance url command in the content rule.
!*************************** OWNER ***************************
owner test 
  content stickyCookie 
    advanced-balance url 
    string prefix "MyCookie=" 
    add service test1 
    add service test2 
    add service test3 
    add service test4 
    port 80 
    protocol tcp 
active
Sticky Based on a Cookie in the HTTP Header or URL

If the cookie could be in either the cookie field of the HTTP header or the URL, use the advanced-balance cookieurl command.

In this configuration, the CSS searches for the cookie first in the cookie field of the HTTP header. If the cookie field does not exist, then the CSS looks for the cookie in the URL. This command is intended for applications where some clients cannot accept cookies but others can.

Using the full configuration of the "Sticky Based on a Configured String in an HTTP Cookie Header" section, the only difference is the advanced-balance cookieurl command in the content rule.
!*************************** OWNER ***************************
owner test 
  content stickyCookie 
    advanced-balance cookieurl 
    string prefix "MyCookie=" 
    add service test1 
    add service test2 
    add service test3 
    add service test4 
    port 80 
    protocol tcp 
active
Where to Go Next

Chapter 5, Where to Go Next, provides information on the location of administrative and configuration tasks, and a contents summary of the CSS administration, configuration, and user guides.

	CSS Getting Started Guide (Software Version 7.40)
	Configuring Sticky Cookies
CSS Getting Started Guide (Software Version 7.40) Index Preface Booting, Logging In, and Getting Started Configuring CSS Basics Configuring the Domain Name Service Configuring Sticky Cookies Where to Go Next Troubleshooting the Boot Process	Download this chapter Configuring Sticky Cookies Download the complete book Cisco Content Services Switch Getting Started Guide (Software Version 7.40), Book-Length PDF (PDF - 1 MB) Table Of Contents Configuring Sticky Cookies Sticky Overview Advanced Load-Balancing Method Using Cookies Sticky Based on a Configured String in an HTTP Cookie Header Sticky Based on a Cookie in a URL Sticky Based on a Cookie in the HTTP Header or URL Where to Go Next Configuring Sticky Cookies This chapter provides information on CSS sticky using cookies. •Sticky Overview •Advanced Load-Balancing Method Using Cookies For detailed information on services, sticky parameters and their uses, and Layer 3, Layer 4, and Layer 5 sticky, refer to the Cisco Content Services Switch Content Load-Balancing Configuration Guide. Sticky Overview When customers visit an e-commerce site, they usually start out by browsing the site, the Internet equivalent of window shopping. Depending on the application, the site may require that the customer become "stuck" to one server once the connection is established, or the application may not require this until the customer starts to build a shopping cart. In either case, once the customer adds items to the shopping cart, it is important that all of the customer's requests get directed to the same server so that all the items are contained in one shopping cart on one server. An instance of a customer's shopping cart is typically local to a particular Web server and is not duplicated across multiple servers. Stickiness is the association between a client and a server that the CSS maintains during a session. Stickiness enables transactions over the Web because the client must remain on the same server for the entire session. Depending on the content rule, the CSS "sticks" a client to an appropriate server after the CSS has determined which load-balancing method to use. If the CSS determines that a client is already stuck to a particular service, then the CSS places the client request on that service, regardless of the load balancing criteria specified by the matched content rule. If the CSS determines that the client is not stuck to a particular service, it applies normal load balancing to the content request. Client cookies uniquely identify clients to the services providing content. A cookie is a small data structure used by a server to deliver data to a Web client and request that the client store the information. In certain applications, the client returns the information to the server to maintain the state between the client and the server. When the CSS examines a request for content and determines through content rule matching that the content is sticky, it examines any cookie or URL present in the content request. The CSS uses this information to place the content request on the appropriate server. Advanced Load-Balancing Method Using Cookies A content rule is "sticky" when additional sessions from the same user or client are sent to the same service as the first connection, overriding normal load balancing. By default, the advanced balancing method is disabled. Use the advanced-balance command to specify an advanced load-balancing method for a content rule that includes stickiness. The advanced-balance command options (cookies, cookieurl, and url) use strings for sticking clients to servers. These options are beneficial when the sticky table limit is too small for your application requirements because the string methods do not use the sticky table. The following sections provide configuration information for: •Sticky Based on a Configured String in an HTTP Cookie Header, using the advance-balanced cookies command •Sticky Based on a Cookie in a URL, using the advance-balanced url command •Sticky Based on a Cookie in the HTTP Header or URL, using the advance-balanced cookieurl command For information on additional advanced load-balancing methods including arrowpoint cookies, refer to the Cisco Content Services Switch Content Load-Balancing Configuration Guide. Sticky Based on a Configured String in an HTTP Cookie Header If the server returns a cookie that is static and uniquely identifies itself, use the advanced-balance cookies command. This command enables the content rule to stick a client to a server based on the configured string found in the HTTP cookie header. A content rule with a sticky configuration set to advanced-balance cookies requires all clients to enable cookies on their browser. In the following configuration, the CSS looks for the cookie in the Cookie: field of the HTTP header: 1. The CSS looks for the configured string prefix, which is the cookie name. In this example, the string prefix in the content rule is MyCookie=. 2. If the CSS finds the prefix, then it looks for the value that matches one of the string values configured in one of the services. For example, the string value for service test 1 is server1. The CSS begins searching for the prefix and value at the beginning of the cookie field in the header and searches the entire field until the end of the field. If the HTTP header spans multiple packets, the CSS searches up to 5 packets by default; however, you can configure the CSS to search up to 20 packets (refer to the global spanning-packets command for more details). 3. If the CSS cannot find the string prefix or match the cookie value with one of the service string values, then the CSS load balances the request according to the configured balance method (roundrobin by default). For more details on what action the CSS takes when it cannot locate the cookie header or the specified cookie string, see the content rule mode sticky-no-cookie-found-action command. configure !************************* GLOBAL *********************** ip route 0.0.0.0 0.0.0.0 10.86.191.174 1 !********************* INTERFACE ********************* interface 3/2 bridge vlan 2 !********************** CIRCUIT ************************ circuit VLAN1 description "client vlan" ip address 10.86.191.161 255.255.255.240 circuit VLAN2 description "server vlan" ip address 10.1.1.254 255.255.0.0 !The string value configured in the service must match the value of the cookie for a particular server. !************************ SERVICE ************************ service test1 ip address 10.1.1.1 string server1 active service test2 ip address 10.1.1.2 string server2 active service test3 ip address 10.1.1.3 string server3 active service test4 ip address 10.1.1.4 string server4 active !The string prefix must match the cookie name. We recommend that you include the `=' as part of the string prefix. !************************* OWNER *********************** owner test content stickyCookie advanced-balance cookies string prefix "MyCookie=" add service test1 add service test2 add service test3 add service test4 port 80 protocol tcp active Sticky Based on a Cookie in a URL If the cookie is present in the URL instead of the cookie field of the HTTP header, use the advanced-balance url command. Some client applications do not accept cookies. When a site depends upon the information in the cookie, administrators sometimes modify the server application so that it appends the cookie data to the parameters section of the URL. The parameters typically follow a "?" at the end of the main data section of the URL. In this configuration, the CSS functions in a similar manner as when using the advanced-balance cookies command; however, the CSS looks in the URL after the `?' for the cookie. Using the full configuration of the "Sticky Based on a Configured String in an HTTP Cookie Header" section, the only difference is the advanced-balance url command in the content rule. !*********************** OWNER *********************** owner test content stickyCookie advanced-balance url string prefix "MyCookie=" add service test1 add service test2 add service test3 add service test4 port 80 protocol tcp active Sticky Based on a Cookie in the HTTP Header or URL If the cookie could be in either the cookie field of the HTTP header or the URL, use the advanced-balance cookieurl command. In this configuration, the CSS searches for the cookie first in the cookie field of the HTTP header. If the cookie field does not exist, then the CSS looks for the cookie in the URL. This command is intended for applications where some clients cannot accept cookies but others can. Using the full configuration of the "Sticky Based on a Configured String in an HTTP Cookie Header" section, the only difference is the advanced-balance cookieurl command in the content rule. !*********************** OWNER *********************** owner test content stickyCookie advanced-balance cookieurl** string prefix "MyCookie=" add service test1 add service test2 add service test3 add service test4 port 80 protocol tcp active Where to Go Next Chapter 5, Where to Go Next, provides information on the location of administrative and configuration tasks, and a contents summary of the CSS administration, configuration, and user guides.
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