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Cisco GSS CLI-Based Global Server Load-Balancing Configuration Guide (Software Version 1.3)
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Index
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Preface
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Introducing the Global Site Selector
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Configuring Resources
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Configuring Source Address Lists
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Configuring Domain Lists
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Configuring Keepalives
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Configuring Answers and Answer Groups
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Building and Modifying DNS Rules
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Configuring DNS Sticky
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Configuring Network Proximity
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Creating and Playing GSLB Configuration Files
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Displaying Global Server Load-Balancing Configuration Information
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Displaying GSS Global Server Load-Balancing Statistics
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Primary GSSM Global Server Load-Balancing Error Messages
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Sticky and Proximity XML Schema Files
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Glossary
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Table Of Contents
Configuring Answers and Answer Groups
Configuring and Modifying Answers
Logging in to the CLI and Enabling Privileged EXEC Mode
Configuring KeepAlive VIP Answers
Configuring ICMP Keepalive VIP Answers
Configuring TCP Keepalive VIP Answer Settings
Configuring HTTP HEAD Keepalive VIP Answer Settings
Configuring KAL-AP Keepalive VIP Answer Settings
Configuring Multiple Keepalives for a VIP Answer Type
Configuring a Name Server-Type Answer
Suspending or Reactivating All Answers in a Location
Configuring and Modifying Answer Groups
Adding Answers to a CRA-Type Answer Group
Adding Answers to an NS-Type Answer Group
Adding Answers to a VIP-Type Answer Group
Suspending or Reactivating All Answers in an Answer Group
Suspending or Reactivating an Answer in an Answer Group
Suspending or Reactivating All Answers in Answer Groups Associated with an Owner
Displaying Answer Group Properties
Configuring Answers and Answer Groups
This chapter describes how to create and configure answers and answer groups for your GSS network. It contains the following major sections:
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Configuring and Modifying Answers
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Configuring and Modifying Answers
In a GSS network, the term answers refers to the resources that respond to content queries. When you create an answer using the primary GSSM, you are identifying a resource on your GSS network to which queries can be directed. This resource provides the requesting client D-proxy with the address of a valid host to serve their request.
GSS answers include the following:
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The GSS groups answers together as resource pools, also referred to as answer groups. From the available answer groups, the GSS can use a maximum of three possible response answer group and balance method clauses in a DNS rule to select the most appropriate resource that serves a user request. Each balance method provides a different algorithm for selecting one answer from a configured answer group. Each clause specifies that a particular answer group serve the request and a specific balance method be used to select the best resource from that answer group.
Depending on the type of answer, further intelligence can be applied to DNS queries by the GSS to choose the best host. For example, a request that is routed to a VIP associated with a Cisco CSS is routed to the best resource based on load and availability, as determined by the CSS. A request that is routed to a CRA is routed to the best resource based on proximity, as determined in a DNS race conducted by the GSS.
This section includes the following procedures:
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Logging in to the CLI and Enabling Privileged EXEC Mode
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To log in to the primary GSSM and enable privileged EXEC mode at the CLI:
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Otherwise, if you are using a direct serial connection between your terminal and the GSSM, use a terminal emulation program to access the CLI. For details about making a direct connection to the GSS device using a dedicated terminal and about establishing a remote connection using SSH or Telnet, refer to the Cisco Global Site Selector Getting Started Guide.
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gssm1.example.com>3.
gssm1.example.com> enablegssm1.example.com#Configuring a VIP-Type Answer
When configuring a VIP-type answer, you have the option to configure one of several different keepalive types or multiple keepalive types to test for that answer. Refer to the "Configuring Multiple Keepalives for a VIP Answer Type" section for more information on configuring multiple keepalives to test for an answer. For a KAL-AP keepalive, configure shared keepalives before you configure your answer. Refer to Chapter 5, Configuring Keepalives for more information on creating shared keepalives.
To configure a VIP-type answer, use the answer vip ip_address command in global server load-balancing configuration mode.
The syntax of this command is:
answer vip ip_address [name name | location name | activate | suspend]
After you enter the answer vip ip_address command, the prompt changes to the answer vip configuration mode where you can optionally specify and configure keepalives for your VIP-type answer.
The options and variables for this command are:
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For example, to create a VIP answer called SEC-LONDON1 and associate it with the London location, enter:
gssm1.example.com# configgssm1.example.com(config)# gslbgssm1.example.com(config-gslb)# answer vip 10.86.209.232 name SEC-LONDON1 location LONDONgssm1.example.com(config-ansvip[ans-ip])To delete a VIP answer, enter:
gssm1.example.com# configgssm1.example.com(config)# gslbgssm1.example.com(config-gslb)# no answer vip 10.86.209.232 name SEC-LONDON1 location LONDONgssm1.example.com(config-gslb)For more information on modifying existing answers, see the "Modifying an Answer" section.
Configuring KeepAlive VIP Answers
After you create an answer, you can choose to configure one of a variety of different keepalive types or multiple keepalive types to test for that answer. The following sections describe how to configure the properties for the individual VIP keepalives, and includes a section on configuring multiple keepalives for an answer. The default values used for each of the VIP keepalives are determined by the global keepalive property settings previously specified (see Chapter 5, Configuring Keepalives).
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Configuring ICMP Keepalive VIP Answers
To define the ICMP keepalives for your VIP answer, use the keepalive type icmp command in answer vip configuration mode. This command sends an ICMP echo message (ping) to the address specified for the VIP answer. The GSS determines the online status by the response received from the device, indicating simple connectivity to the network.
The syntax for this command is:
keepalive type icmp [shared ip_address | retries number | successful-probes number]
The variables and options for this command are:
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For example, to configure an ICMP keepalive for the VIP-type answer servicing VIP address 10.86.209.232, enter:
gssm1.example.com(config-gslb)# answer vip 10.86.209.232gssm1.example.com(config-ansvip[ans-ip])keepalive type icmp retries 2gssm1.example.com(config-ansvip[ans-ip])See the "Configuring Multiple Keepalives for a VIP Answer Type" section for details on configuring multiple keepalives to test for a VIP-type answer.
Configuring TCP Keepalive VIP Answer Settings
To define the TCP keepalive for your VIP answer, use the keepalive type tcp command in answer vip configuration mode. This command sends a TCP handshake to the address specified for the VIP answer and port number of the remote device to determine service viability (three-way handshake and connection termination method), returning the online status of the device.
The syntax for this command is:
keepalive type tcp [shared ip_address | port number | retries number | successful-probes number | termination {graceful | reset}]
The variables and options for this command are:
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For example, to configure a TCP keepalive for the VIP-type answer servicing VIP address 192.168.200.1, enter:
gssm1.example.com(config-gslb)# answer vip 192.168.200.1gssm1.example.com(config-ansvip[ans-ip])keepalive type tcp port 23 successful-probes 4gssm1.example.com(config-ansvip[ans-ip])See the "Configuring Multiple Keepalives for a VIP Answer Type" section for details on configuring multiple keepalives to test for a VIP-type answer.
Configuring HTTP HEAD Keepalive VIP Answer Settings
To define the HTTP HEAD keepalive for your VIP answer, use the keepalive type http-head command in answer vip configuration mode. This command sends a TCP-format HTTP HEAD request to an origin web server at the address specified for the VIP answer. The GSS determines the online status of the device in the form of an HTTP Response Status Code of 200 (for example, HTTP/1.0 200 OK) from the server as well as information on the web page status and content size.
The syntax for this command is:
keepalive type http-head [host-tag domain_name | path path | port number | retries number | shared ip_address | successful-probes number | termination {graceful | reset}]
The variables and options for this command are:
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For example, to configure anHTTP HEAD keepalive for the VIP-type answer servicing VIP address 192.168.200.1, enter:
gssm1.example.com(config-gslb)# answer vip 192.168.200.1gssm1.example.com(config-ansvip[ans-ip])keepalive type http-head host-tag WWW.HOME.COM termination gracefulgssm1.example.com(config-ansvip[ans-ip])See "Configuring Multiple Keepalives for a VIP Answer Type" for details on configuring multiple keepalives to test for a VIP-type answer.
Configuring KAL-AP Keepalive VIP Answer Settings
To define the KAL-AP keepalive for your VIP answer, use the keepalive type kalap command in answer vip configuration mode. This command sends a detailed query to the Cisco CSS or CSM at the address specified for the VIP answer to extract load and availability. The GSS determines the online status when the SLBs respond with information about a hosted domain name, host VIP address, or a configured tag on a content rule.
The syntax for this command is:
keepalive type kalap {tag ip_address {tag_name} | vip ip_address}}
The variables and options for this command are:
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For example, to configure a KAL-AP keepalive for the VIP-type answer servicing VIP address 192.168.200.1, enter:
gssm1.example.com(config-gslb)# answer vip 192.168.200.1gssm1.example.com(config-ansvip[ans-ip]) keepalive type kalap tag 192.168.50.41 TAG1gssm1.example.com(config-ansvip[ans-ip])See the "Configuring Multiple Keepalives for a VIP Answer Type" section for details on cofiguring multiple keepalives to test for a VIP-type answer.
The Content and Application Peering Protocol (CAPP) may not recognize dropped fragments when a KAL-AP keepalive spans multiple datagrams due to large payloads. When the KAL-AP keepalive spans multiple datagrams and one of the spanned packets is dropped, the GSS does not retry the request. Instead, the GSS waits until the next period and sends the packets again. This results in the dropped datagram not getting updated load values on the VIPs that expect them. This behavior typically occurs in situations where the GSS consumes the full datagram (roughly 1.4 K) with tag names or VIP addresses. Otherwise, all data fits perfectly in a single datagram.
To resolve this behavior, use the VIP format for KAL-AP when you need the GSS to send a detailed query on load for hundreds of VIPs configured to a single primary or optional secondary (backup) IP address. Another solution is to use the tag format for KAL-AP, but to limit the length of the tag name to ensure that the packets do not exceed 1.4K.
Configuring Multiple Keepalives for a VIP Answer Type
The primary GSSM supports the assignment of multiple keepalives and/or destination ports for a single VIP answer. You can configure a maximum of five different keepalives for a VIP answer, in a mix and match configuration of ICMP, TCP, HTTP HEAD, and KAL-AP VIP keepalive types. However, the primary GSSM supports only a single usage of a shared keepalive and a single KAL-AP keepalive when specifying multiple keepalive types.
For TCP or HTTP HEAD keepalives, you may also specify different destination ports. The multi-port keepalive capability allows you monitor a single server and check responses from multiple ports. As long as all the keepalives are successful, the GSS device considers the resource active and continues to redirect client traffic to the server. Servers that yield unsuccessful connections are marked as unavailable; subsequent successful connections to the server will reinstate it as available to be used as a resource.
When using multiple keepalive types, the VIP answer status is a logical AND function of all keepalive probes associated with an answer, resulting in a consolidation of results from each answer.
For example, to configure TCP- and HTTP HEAD-type keepalives for multiple ports for the VIP-type answer servicing VIP address 192.168.200.1, enter:
gssm1.example.com(config-gslb)# answer vip 192.168.200.1gssm1.example.com(config-ansvip[ans-ip])keepalive type tcp port 80gssm1.example.com(config-ansvip[ans-ip])keepalive type tcp port 443gssm1.example.com(config-ansvip[ans-ip])keepalive type http-head port 8080gssm1.example.com(config-ansvip[ans-ip])exitgssm1.example.com(config-gslb)#To configure TCP- and HTTP HEAD-type keepalives for multiple ports for the VIP-type answer named MPORT_KALE_MIX that services VIP address 192.168.200.1, enter:
gssm1.example.com(config-gslb)# answer vip 192.168.200.1 name MPORT_KALE_MIXgssm1.example.com(config-ansvip[ans-ip])keepalive type tcp port 80gssm1.example.com(config-ansvip[ans-ip])keepalive type tcp port 443gssm1.example.com(config-ansvip[ans-ip])keepalive type http-head port 8080gssm1.example.com(config-ansvip[ans-ip])exitgssm1.example.com(config-gslb)#
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To configure KAL-AP-, TCP- and HTTP HEAD-type keepalives for the VIP-type answer servicing VIP address 192.168.200.1, enter:
gssm1.example.com(config-gslb)# answer vip 192.168.200.1gssm1.example.com(config-ansvip[ans-ip]) keepalive type kalap tag 192.168.50.41 TAG1gssm1.example.com(config-ansvip[ans-ip]) keepalive type tcp port 80gssm1.example.com(config-ansvip[ans-ip]) keepalive type tcp port 443gssm1.example.com(config-ansvip[ans-ip]) keepalive type http-head port 8080gssm1.example.com(config-ansvip[ans-ip])exitgssm1.example.com(config-gslb)#Configuring a CRA-Type Answer
The content routing agent (CRA) answer type relies on content routing agents and the GSS to choose a suitable answer for a given query based on the proximity of two or more possible hosts to the requesting D-proxy.
With the CRA-type answer, the requests received from a particular D-proxy are served by the content server that responds first to the request. The response time is measured using a DNS race and is coordinated by the GSS and content routing agents running on each content server. In the race, multiple hosts respond simultaneously to a request. The server with the fastest response time (the shortest network delay between itself and the client's D-proxy) is chosen to serve the content.
The CRA-type answer is designed to work with the GSS when you select the boomerang balance method with a DNS rule (utilizing the boomerang server component of the GSS).
Closeness is determined when multiple hosts reply to the requesting D-proxy simultaneously in what is referred to as a "DNS race." The GSS coordinates the start of the race so that all CRAs initiate their response at the same time. The first DNS reply to reach the D-proxy is chosen by the name server as the host containing the answer.
To configure a CRA-type answer, use the answer cra ip_address command in global server load-balancing configuration mode. The syntax of this command is:
answer cra ip_address [enable | disable | delay number | name name | location name | activate | suspend]
The variables and options for this command are:
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For example, to create a CRA-type answer with a one-way delay, enter:
gssm1.example.com# configgssm1.example.com(config)# gslbgssm1.example.com(config-gslb)# answer cra 10.86.209.22 name CRA-ANS1 delay 3gssm1.example.com(config-gslb)To delete a CRA-type answer, enter:
gssm1.example.com(config-gslb)# no answer cra 10.86.209.22 name CRA-ANS1 delay 3gssm1.example.com(config-gslb)For information on modifying existing answers, see the "Modifying an Answer"section.
Configuring a Name Server-Type Answer
A name server (NS)-type answer specifies the IP address of a DNS name server to which DNS queries are forwarded from the GSS. Using the name server forwarding feature, queries are forwarded to a non-GSS name server for resolution, with the answer passed back to the GSS name server and from there to the requesting D-proxy. The name server-type answer acts as a guaranteed fallback resource. A fallback resource can resolve requests that the GSS cannot resolve itself either because the requested content is unknown to the GSS or because the resources that typically handle such requests are unavailable.
To configure a NS-type answer, use the answer ns ip_address command in global server load-balancing configuration mode. The syntax of this command is:
answer ns ip_address [enable | disable | name name | domain name | location name | activate | suspend]
The variables and options for this command are:
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For example, to create an NS-type answer that specifies a domain name server, enter:
gssm1.example.com# configgssm1.example.com(config)# gslbgssm1.example.com(config-gslb)# answer ns 10.86.209.4 domain WWW.HOME.COM enablegssm1.example.com(config-gslb)To delete a NS-type answer, enter:
gssm1.example.com(config-gslb)# no answer ns 10.86.209.4 domain WWW.HOME.COM enablegssm1.example.com(config-gslb)For information on modifying existing answers, see the "Modifying an Answer" section.
Modifying an Answer
Once you have configured your answers, you can modify them at any time. However, once an answer is created and named, you cannot modify its type (for example, from VIP to CRA), its IP address, or its name.
To modify an existing answer:
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The syntax of this command is:
answer {cra | ns | vip}
The options are:
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For example, to first display the answer property settings, then change the one-way delay time for an existing CRA-type answer, enter:
gssm1.example.com(config-gslb)# show gslb-config answer...answer cra 192.168.50.41 delay 2 activateanswer ns 172.16.27.4 domain EXAMPLE.COM activateanswer vip 172.16.27.6 name ansvip2 activatekeepalive type tcp port 180 activatekeepalive type tcp port 88 activate...gssm1.example.com(config-gslb)# answer cra 192.168.50.41 delay 5gssm1.example.com(config-gslb)#In order to modify a named answer, you must specify its name, type, and IP address. For example, to modify the answer named ANSVIP2, you must enter:
gssm1.example.com(config-gslb)# answer vip 172.16.27.6 name ANSVIP2 delay 100gssm1.example.com(config-gslb)#Displaying Answer Properties
Use the show gslb-config answer command to display the current property settings for all answer types.
The syntax of this command is:
show gslb-config answer
For example, enter:
gssm1.example.com(config-gslb)# show gslb-config answeranswer cra 192.168.50.41 delay 2 activeanswer ns 172.16.27.4 domain EXAMPLE.COM activeanswer vip 172.16.27.6 name ansvip2 activekeepalive type tcp port 180 activeanswer vip 192.168.50.30 activekeepalive type tcp port 88 activeanswer vip 192.168.50.2 name ansvip activekeepalive type icmp activekeepalive type tcp port 88 activekeepalive type tcp port 80 activegssm1.example.com(config-gslb)#To display the property settings based on IP address and answer type, enter:
gssm1.example.com(config-gslb)# show gslb-config answer 172.16.27.6 vipanswer vip 172.16.27.6 name ansvip2 activekeepalive type tcp port 180 activegssm1.example.com(config-gslb)#To display the property settings based on an answer name, enter:
gssm1.example.com(config-gslb)# show gslb-config answer ansvip2answer vip 172.16.27.6 name ansvip2 activekeepalive type tcp port 180 activegssm1.example.com(config-gslb)#Suspending an Answer
To temporarily stop the GSS from using an active answer, modify the answer by issuing the suspend option for the answer command. Suspending prevents that answer from being used by any of the currently configured DNS rules.
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To suspend an answer:
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For example, to suspend the NS-type answer that queries the domain server at EXAMPLE.COM, enter:
gssm1.example.com(config-gslb)# show gslb-config answer...answer cra 192.168.50.41 delay 2 activeanswer ns 172.16.27.4 domain EXAMPLE.COM activeanswer vip 172.16.27.6 name ansvip2 activekeepalive type tcp port 180 active...gssm1.example.com(config-gslb)# answer ns 172.16.27.4 domain EXAMPLE.COM suspendgssm1.example.com(config-gslb)#To reactivate a suspended answer, use the activate feature (see the "Reactivating an Answer" section).
Reactivating an Answer
To reactivate a suspended answer, you modify the specific answer by issuing the activate option (for the answer command).
To reactivate an answer:
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For example, to reactivate the NS-type answer that queries the domain server at EXAMPLE.COM, enter:
gssm1.example.com(config-gslb)# show gslb-config answer...answer cra 192.168.50.41 delay 2 activeanswer ns 172.16.27.4 domain EXAMPLE.COM suspendanswer vip 172.16.27.6 name ansvip2 activekeepalive type tcp port 180 active...gssm1.example.com(config-gslb)# answer ns 172.16.27.4 domain EXAMPLE.COM activategssm1.example.com(config-gslb)#Suspending or Reactivating All Answers in a Location
You can group and manage answers according to an established GSS location. Using a location to manage your answers makes it easier for you to quickly suspend or activate answers in a particular area of your network, for example, shutting down one or more data centers for the purposes of software upgrades or regular maintenance.
The GSS automatically detects and routes requests around suspended answers.
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To suspend or reactivate answers based on their location, use the location command with the suspend-all-answers and activate-all-answers options.
If desired, use the show gslb-config location command to display the currently configured locations. See Chapter 2, Displaying Resource Information, for more information about this command.
For example, to suspend all answers based on the location Normandy, enter:
gssm1.example.com(config)# gslbgssm1.example.com(config-gslb)# location Normandy suspend-all-answersgssm1.example.com(config-gslb)#To reactivate all answers based on the location Normandy, enter:
gssm1.example.com(config)# gslbgssm1.example.com(config-gslb)# location Normandy activate-all-answersgssm1.example.com(config-gslb)#Deleting an Answer
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To delete an answer:
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For example, to delete the VIP-type answer that queries IP address 192.168.50.30 and all keepalives for that answer, enter:
gssm1.example.com(config-gslb)# show gslb-config answer...answer cra 192.168.50.41 delay 2 activateanswer ns 172.16.27.4 domain EXAMPLE.COM activateanswer vip 172.16.27.6 name ansvip2 activatekeepalive type tcp port 180 activateanswer vip 192.168.50.30 activatekeepalive type tcp port 88 activateanswer vip 192.168.50.2 name ansvip activatekeepalive type icmp activatekeepalive type tcp port 88 activatekeepalive type tcp port 80 activatekeepalive type tcp activate...gssm1.example.com(config-gslb)# no answer vip 192.168.50.30gssm1.example.com(config-gslb)#In order to delete a named answer, you must specify its name, type, and IP address. For example, to delete the answer named ANSVIP2, you must enter:
gssm1.example.com(config-gslb)# no answer vip 172.16.27.6 name ANSVIP2gssm1.example.com(config-gslb)#Configuring and Modifying Answer Groups
Answer groups are lists of GSS resources that are candidates to respond to DNS queries received from a user for a hosted domain. By using the DNS rules feature, you associate these lists of network resources with a particular balance method that is used to resolve the request.
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A DNS rule can have a maximim of three balance clauses. Each balance clause specifies a different answer group from which an answer can be chosen after taking load threshold, order, and weight factors into account for each answer.
Before creating your answer groups, configure the answers that make up those groups. See the "Configuring and Modifying Answers" section for more information on creating GSS answers.
This section includes the following procedures:
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Creating an Answer Group
To create an answer group, use the answer-group command in global server load-balancing configuration mode.
The syntax of this command is:
answer-group name {owner name type {cra | ns |vip }}
After you enter the answer-group command, the prompt changes to the answer group configuration mode, where you add previously configured answers to the group.
The variables and options for this command are:
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The maximum number of answers that you can place in each of these answer groups is 20 for a CRA answer group, 30 for an NS answer group, and 100 for a VIP answer group.
For example, to create a VIP answer group, enter:
gssm1.example.com(config)# gslbgssm1.example.com(config-gslb)# answer-group ANSGRPVIP1 owner WEB-SERVICES type vipgssm1.example.com(config-gslb-agvip[ag-name])#For example, to delete a VIP answer group, enter:
gssm1.example.com(config)# gslbgssm1.example.com(config-gslb)# no answer-group ANSGRPVIP1 owner WEB-SERVICES type vipgssm1.example.com(config-gslb)#Refer to the following sub-sections for instructions on adding answers to an answer group:
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Adding Answers to a CRA-Type Answer Group
After you create a CRA-type answer group, add previously configured CRA-type answers to the group using the answer-add command in the answer group configuration mode.
The syntax for this command is:
answer-add ip_address [activate | name | suspend]
The variables and options for this command are:
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For example, to add answers to and configure a CRA answer group named ANSGRPCRA3, enter:
gssm1.example.com(config-gslb-agcra[ag-name])# answer-add 192.168.10.1 name www-boston-1gssm1.example.com(config-gslb-agcra[ag-name])# answer-add 192.172.24.1 name www-ny-1gssm1.example.com(config-gslb-agcra[ag-name])# answer-add 192.186.14.1 name www-atlanta-1gssm1.example.com(config-gslb-agcra[ag-name])#To delete an answer from a CRA answer group, enter:
gssm1.example.com(config-gslb-agcra[ag-name])# no answer-add 192.186.14.1 name www-atlanta-1Adding Answers to an NS-Type Answer Group
After you create an NS-type answer group, add previously configured NS-type answers to the group using the answer-add command in the answer group configuration mode.
The syntax for this command is:
answer-add ip_address [name | order number | weight number | activate | suspend]
The variables and options for this command are:
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For more information on the order and weight settings, refer to the "Balance Methods" section in Chapter 1, Introducing the Global Site Selector.
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For example, to add answers to and configure an NS answer group named ANSGRPNS1, enter:
gssm1.example.com(config-gslb-agns[ag-name])# answer-add 192.168.10.1 name www-zurich-1 order 10gssm1.example.com(config-gslb-agns[ag-name])# answer-add 192.172.20.1 name www-barcelona-1 order 20gssm1.example.com(config-gslb-agns[ag-name])# answer-add 192.188.30.1 name www-brussels-30gssm1.example.com(config-gslb-agns[ag-name])#To delete an answer from an NS answer group, enter:
gssm1.example.com(config-gslb-agns[ag-name)# no answer-add 192.168.10.1 name www-zurich-1 order 10Adding Answers to a VIP-Type Answer Group
After you create a VIP-type answer group, add previously configured VIP-type answers to the group using the answer-add command in the answer group configuration mode.
The syntax for this command is:
answer-add ip_address [name | load-threshold number | order number | weight number | activate | suspend]
The variables and options for this command are:
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For more information on the order, weight, and load threshold settings, refer to the "Balance Methods" section in Chapter 1, Introducing the Global Site Selector.
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For example, to add answers to and configure a VIP answer group named ANSGRPVIP1, enter:
gssm1.example.com(config-gslb-agvip[ag-name])# answer-add 192.168.30.1 name www-hk-1 weight 1gssm1.example.com(config-gslb-agvip[ag-name])# answer-add 192.174.20.1 name www-sf-1 weight 2gssm1.example.com(config-gslb-agvip[ag-name])# answer-add 192.188.40.1 name www-london-1 weight 4gssm1.example.com(config-gslb-agvip[ag-name])#To delete an answer from a VIP answer group, enter:
gssm1.example.com(config-gslb-agvip[ag-name])# no answer-add 192.168.30.1 name www-hk-1 weight 1Modifying an Answer Group
Once you create your answer groups, use the CLI in the primary GSSM to make modifications to their configurations, such as adding and removing answers, or changing the order, weight, and load thresholds of the individual answers. Answers can belong to more than one answer group. However, once you add answers to an answer group, you cannot change the type of an answer group (for example, from VIP to CRA).
To modify an answer group:
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For example, to change the order setting for an answer in the VIP answer group ANSVIP4, enter:
gssm1.example.com(config-gslb)# answer-group ANSGRPVIP4 owner WEB-SERVICES type vipgssm1.example.com(config-gslb-agvip[ag-name])# answer-add 192.168.30.1 name www-hk-1 order 10 comments "CHANGED ORDER 12/01/05"gssm1.example.com(config-gslb-agvip[ag-name])#To change the owner of the NS answer group ANSNS2, enter:
gssm1.example.com(config-gslb)# answer-group ANSGRPNS2 owner E-COMMERCE type nsgssm1.example.com(config-gslb-agns[ag-name])#Suspending or Reactivating All Answers in an Answer Group
To temporarily stop the GSS from using all answers in an active answer group, modify the answer group by issuing the no activate-all-answers command in the answer group configuration mode. Suspending prevents that answer group from being used by any of the currently configured DNS rules. Suspending the answers in one answer group also affects any other answer groups to which those answers belong.
To reactivate the answers in the answer group, use the activate-all-answers command in the answer group configuration mode for a specific answer group.
To suspend all answers in an answer group:
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For example, to suspend all answers in the vip-type answer group ANSGRPVIP4, enter:
gssm1.example.com(config-gslb)# answer-group ANSGRPVIP4 owner WEB-SERVICES type vipgssm1.example.com(config-gslb-agvip[ag-name])# no activate-all-answersgssm1.example.com(config-gslb-agvip[ag-name])#To reactivate all answers in a suspended answer group, use the activate-all-answers command.
For example, enter:
gssm1.example.com(config-gslb)# answer-group ANSGRPVIP4 owner WEB-SERVICES type vipgssm1.example.com(config-gslb-agvip[ag-name])# activate-all-answersgssm1.example.com(config-gslb-agvip[ag-name])#Suspending or Reactivating an Answer in an Answer Group
To temporarily stop the GSS from using an answer in an active answer group, you modify the answer group by issuing the suspend option for the answer-add command in the answer group configuration mode. Suspending prevents that answer in the answer group from being used by any of the currently configured DNS rules.
Note
To reactivate an answer in the answer group, use the active option (for the answer-add command) in the answer group configuration mode.
To suspend an answer in an answer group:
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For example, to suspend the answer www-sf-1 in the vip-type answer group ANSGRPVIP4, enter:
gssm1.example.com(config-gslb)# answer-group ANSGRPVIP4 owner WEB-SERVICES type vipgssm1.example.com(config-gslb-agvip[ag-name])# answer-add 192.168.30.1 suspendgssm1.example.com(config-gslb-agvip[ag-name])#To reactivate a suspended answer in an answer group, use the activate command.
For example, enter:
gssm1.example.com(config-gslb)# answer-group ANSGRPVIP4 owner WEB-SERVICES type vipgssm1.example.com(config-gslb-agvip[ag-name])# answer-add 192.168.30.1 activategssm1.example.com(config-gslb-agvip[ag-name])#Suspending or Reactivating All Answers in Answer Groups Associated with an Owner
You can group and manage answers added to answer groups according to GSS owner. Using a GSS owner to manage your answer groups enables you to quickly suspend or activate related answers.
To suspend or reactivate all answers in answer groups associated with a GSS owner, issue the suspend-all-answers and activate-all-answers options (for the owner command).
If desired, use the show gslb-config answer-group command to display the currently configured owners, answers, and answer groups.
For example, to suspend all answers in answer groups associated with the owner WEB-SERVICES, enter:
gssm1.example.com(config)# gslbgssm1.example.com(config-gslb)# owner WEB-SERVICES suspend-all-answersgssm1.example.com(config-gslb)#To reactivate all answers in answer groups associated with the owner WEB-SERVICES, enter:
gssm1.example.com(config)# gslbgssm1.example.com(config-gslb)# owner WEB-SERVICES activate-all-answersgssm1.example.com(config-gslb)#Displaying Answer Group Properties
Use the show gslb-config answer-group command to display the current property settings for all answer groups.
The syntax of this command is:
show gslb-config answer-group
For example, enter:
gssm1.example.com(config-gslb)# show gslb-config answer-group...answer-group AGROUP1 owner "OWNER1" type nsanswer-group AGROUP2 owner "OWNER2" type craanswer-group AGROUP3 owner System type vip...To display the properties for an answer group based on an answer group name, enter:
gssm1.example.com(config-gslb)# show gslb-config answer-group ANGROUP1answer-group AGROUP1 owner "OWNER1" type nsDeleting an Answer Group
Caution
Before deleting an answer group, verify that none of your DNS rules reference the answer group that you are about to delete. If necessary, deselect the answer group from the DNS rule. Refer to Chapter 7, Building and Modifying DNS Rules, for information about modifying a DNS rule.
Deleting an answer group does not delete the answers contained in the answer group.
To delete an answer group:
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For example, to delete the VIP-type answer group ANSGRPVIP1, enter:
gssm1.example.com(config-gslb)# show gslb-config answer-groupanswer-group ANSGRPVIP1 owner OWNR1 type vipanswer-group ANSGRPVIP2 owner System type vipgssm1.example.com(config-gslb)# no answer-group ANSGRPVIP1gssm1.example.com(config-gslb)#Where to Go Next
Chapter 7, Building and Modifying DNS Rules, describes constructing the DNS rules that govern all global server load balancing on your GSS network.
