Product Documentation

Configure parent-child topology

In a parent-child topology, at the top level are parent sites, which have peer relationships with other parents. Each parent can have multiple child sites, and each parent site exchanges health information with its child sites and with other parent sites. However, a child site communicates only with its parent site.

The following figure shows the workflow involved in a GSLB parent-child topology configuration.

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Before you begin configuring the parent-child topology deployment, make sure you have configured a standard load balancing setup for each server farm or data center.

Also, for synchronizing the GSLB configuration across the GSLB sites in the deployment, make sure that:

  • Local GLSB Sites are configured on all the appliances in the GSLB configuration.
  • You have enabled management access on all the GSLB Sites in the configuration.
  • You have configured the firewall to accept the auto synchronization and MEP connections.
  • All the Citrix ADC appliances participating as sites should have the sameCitrix ADC software version (the sites are not in a master-slave relationship).
  • The RPC node password is same across all the GSLB sites in the GSLB configuration.

To configure a parent-child deployment by using the wizard

On the Configuration tab, do the following:

  1. Navigate to Traffic Management > GSLB, and then click Get Started.
  2. If you have not configured an ADNS server or a DNS virtual server for the site, you can do it now.
    1. Click View and then click Add.
    2. Enter the service name, IP address and select the protocol (ADNS/ADNS_TCP) through which the data is exchanged with the service.
  3. Select Parent-Child Topology.
  4. In the Select the site type field, choose;
    • Parent – When configuring the parent site, you must configure its associated child sites and also configure the other parent sites in the GSLB setup.
    • Child – When configuring the child site, you must configure only the child site and its parent site.

To configure a parent site

  1. Enter the fully qualified domain name and specify the time period for which the record must be cached by DNS proxies.
  2. Configure the GSLB sites. Each site must be configured with a local GSLB site, and each site’s configuration must include all the other sites as remote GSLB sites. There can be only one local site. All other sites are remote sites. If the specified site IP address is owned by the appliance (for example, a MIP address or SNIP address), the site is a local site. Otherwise, it is a remote site.
  3. Enter the site details, such as the site name and site IP address.
    1. Select the site type.
    2. Optionally, change the RPC password and, if necessary, secure it.
    3. If a monitor is to be bound to the GSLB service, select the condition under which the monitor is to monitor the service.  This will be effective only after a monitor is bound to the services. The possible conditions are:
      • Always. Monitor the GSLB service at all times.
      • MEP Fails. Monitor the GSLB service only when the exchange of metrics through MEP fails.
      • MEP Fails and Service is DOWN. Exchange of metrics through MEP is enabled but the status of the service, updated through metrics exchange, is DOWN.
  4. Configure the GSLB services.
    1. Enter the service details such as service name, service type, and port number.
    2. Associate the service with a site (local or remote) by selecting the GSLB site to which the GSLB service belongs.
    3. Select the monitor that must be bound to the service when MEP fails, if required. The service can be an existing server, or you can create a new server or a virtual server.
      • To associate an existing server, select the server name. The service IP address is auto-populated.
      • To associate a new server, create a server by entering the server IP details and its public IP address and the public port number.
      • To associate a virtual server, select an already existing virtual server or click + and add a new virtual server. This vserver is the load balancing vserver to which this GSLB service will be associated. If the public IP address is different from the server IP, which can happen in a NAT environment, enter the public IP address and the public port number.
  5. Configure the GSLB virtual servers.
    1. Enter the name of the GSLB virtual server name and select the DNS record type.
    2. Click > in the Select Service box and choose the GSLB services to be bound to the GSLB virtual server.
    3. Click > in the Domain Binding box to view the domain name that is bound to the GSLB virtual server.
    4. Choose the GSLB method for selecting the best-performing GSLB service. The default values for GSLB method, backup method, and dynamic weight are automatically populated by default. You can change them if required.
      • If you choose the Algorithm based method, select the primary and backup methods and also specify the dynamic weight option.
      • If you choose the Static Proximity method, select the backup method and the dynamic weight method. Also, provide the location of the database file by clicking the > icon or add a new location by clicking + in the Select a location database box.
      • If you choose the Dynamic Proximity (RTT) method, select the backup method and specify the service weight and the RTT value based on which the best-performing service is to be selected.
  6. Click Done if the configuration is complete. The GSLB dashboard appears.
  7. If you have modified the GSLB parent-site configuration, click Auto Synchronize GSLB to synchronize the configuration to the other parent sites in the GSLB setup. In a parent-child topology, synchronization for the child sites is skipped.
    • Before synchronization, make sure that the local site’s configuration includes information about the remote sites.
    • If real-time synchronization is enabled, you do not have to click Auto Synchronize GSLB. The synchronization happens automatically. To enable real time synchronization, do the following:
      1. Navigate to Traffic Management > GSLB > Dashboard and click Change GSLB Settings.
      2. Select the Automatic Config Sync check box.
  8. Click Test GSLB Setup to make sure that the ADNS services or the DNS servers are responding with the correct IP address for the domain name that is configured in the GSLB setup.

To configure a child site

  1. Configure the GSLB sites.
    1. Enter the site details, such as the site name and site IP address.
    2. Select the site type.
    3. Optionally, change the RPC password and, if necessary, secure it. 4. If a monitor is bound to the GSLB service, select the condition under which the monitor is to monitor the service. The possible conditions are:
      • Always. Monitor the GSLB service at all times.
      • MEP Fails. Monitor the GSLB service only when the exchange of metrics through MEP fails.
      • MEP Fails and Service is DOWN. Exchange of metrics through MEP is enabled but the status of the service, updated through metrics exchange, is DOWN.
  2. Click Done if the configuration is complete. The GSLB dashboard appears.
  3. Click Test GSLB Setup to make sure that the ADNS services or the DNS servers are responding with the correct IP address for the domain name that is configured in the GSLB setup.

Configure parent-child topology