Citrix ADC

Manual synchronization between sites participating in GSLB

The manual synchronization of GSLB configuration across the master site and the slave sites is performed in the following manner:

  • The master site detects the differences between the configuration of its own site and the slave site.
  • The master site applies the difference in configuration to the slave site.
  • The master site performs the configuration synchronization with all the slave sites in the GSLB setup, and completes the synchronization process.

Important: After a GSLB configuration is synchronized, the configuration cannot be rolled back on any of the GSLB sites. Perform the synchronization only if you are sure that the synchronization process does not overwrite the configuration on the remote site. Site synchronization is undesirable when the local and remote sites have different configurations by design, which leads to site outage. If some commands fail and some commands succeed, the successful commands are not rolled back.

Points to note

  • If you force a synchronization (use the ‘force sync’ option), the Citrix ADC appliance deletes the GSLB configuration from the slave site. Then, master site configures the slave site to make it similar to its own site.
  • During synchronization, if a command fails, synchronization is not aborted. The error messages are logged into an .err file in the /var/netscaler/gslb directory.
  • If you use the saveconfig option, the sites participating in the synchronization process automatically save their configuration, in the following way:
    • The master site saves its configuration immediately before it initiates the synchronization process.
    • The slave sites save their configuration after the process of synchronization is complete. A slave site saves its configuration only if the configuration difference was applied successfully on it. If synchronization fails on a slave site, you must manually investigate the cause of the failure and take corrective actions.

To synchronize a GSLB configuration by using the CLI:

At the command prompt, type the following commands to synchronize GSLB sites and verify the configuration:

sync gslb config [-preview | -forceSync <string> | -nowarn | -saveconfig] [-debug]
show gslb syncStatus

Example:

sync gslb config

[WARNING]: Syncing config may cause configuration loss on other site.

Please confirm whether you want to sync-config (Y/N)? [N]:y

Sync Time: Dec 9 2011 10:56:9

Retrieving local site info: ok

Retrieving all participating gslb sites info: ok

Gslb_site1[Master]:

Getting Config: ok

Gslb_site2[Slave]:

Getting Config: ok

Comparing config: ok

Applying changes: ok

Done

To synchronize a GSLB configuration by using the GUI:

  1. Navigate to Traffic Management > GSLB > Dashboard.
  2. Click Auto Synchronization GSLB and select ForceSyn.
  3. In GSLB Site Name, select the GSLB sites that are to be synchronized with the master node configuration.

Previewing GSLB synchronization

By previewing the GSLB synchronization operation, you can see the differences between the master node and each slave node. If there are any discrepancies, you can troubleshoot before synchronizing the GSLB configuration.

To preview the GSLB synchronization output by using the CLI:

At the command prompt, type the following command:

sync gslb config -preview

To preview the GSLB synchronization output by using the GUI:

  1. Navigate to Configuration > Traffic Management > GSLB > Dashboard.
  2. Click Auto Synchronization GSLB and select Preview.
  3. Click Run. A progress window displays any discrepancies in the configuration.

Debugging the commands triggered during synchronization process

You can view the status (success or failure) of each command triggered during the synchronization process and troubleshoot accordingly.

To debug the GSLB synchronization commands by using the CLI:

At the command prompt, type the following command:

sync gslb config -debug

To debug the GSLB synchronization commands by using the GUI:

  1. Navigate to Configuration > Traffic Management > GSLB > Dashboard.
  2. Click Auto Synchronization GSLB and select Debug.
  3. Click Run. A progress window displays the status of each command triggered during synchronization.

Manual synchronization between sites participating in GSLB