10

Adding a 3-DNS Controller to an Existing Network

• Working with multiple 3-DNS Controllers
  
  
• Preparing to add a second 3-DNS Controller to your network
  
  
• Running the 3dns_add script
  
  
• Verifying the configuration

Working with multiple 3-DNS Controllers

When you are working with more than one 3-DNS Controller in your network, and you want the systems to load balance to the same virtual servers, you can create your entire configuration on one system and then add the second system using the 3dns_add script. The 3dns_add script copies the entire configuration from the first system onto the second system, and synchronizes all of the settings between the systems. (For more information about sync groups, see Working with a sync group .)

The following sections of this chapter describe the procedures you follow to add a 3-DNS Controller into a network that already has at least one 3-DNS Controller configured and working properly. If you are adding the first 3-DNS Controller to your network, refer to Chapter 5, Essential Configuration Tasks .

Important: If you are adding a second 3-DNS Controller to your network but do not want it to be in the same sync group as your first system, or you want the second 3-DNS Controller to load balance to a different set of virtual servers, then do not use the 3dns_add script.

Preparing to add a second 3-DNS Controller to your network

Before you run the 3dns_add script on any additional 3-DNS Controllers you are adding to your network, you should complete the following tasks:

• Physically install the second 3-DNS Controller in its data center. (For more information on hardware installation, refer to the Platform Guide that shipped with the unit.)
  
  
• Run the Setup utility on the second system. (For more information on the Setup utility, see Chapter 3, Using the Setup Utility , or if you are running the 3-DNS Controller module on a BIG-IP system, refer to the BIG-IP Reference Guide .)
  
  
• Make the existing 3-DNS Controller aware of the IP address, fully-qualified domain name, and data center location of the second 3-DNS Controller. (See Making the existing controller aware of the new controller .)
  
  
• Add the new 3-DNS Controller to the sync group of the existing 3-DNS Controller.
  
  

Completing these tasks ensures that when you run the 3dns_add script, the second 3-DNS Controller successfully copies the configuration information from the first 3-DNS Controller.

Warning:
If you are using a sync group, we strongly recommend that you run the 3dns_add script to add additional 3-DNS Controllers to your network. If you do not use the script, you risk overwriting your current configuration.

A note about 3-DNS sync groups and Link Controllers

If you have both 3-DNS Controllers and Link Controllers in your network, you can add the Link Controllers to the 3-DNS sync group. While the process is similar to adding a new 3-DNS Controller to an existing sync group, it is not the same. For details on adding a Link Controller to a 3-DNS sync group, refer to the BIG-IP Link Controller Solutions Guide, Chapter 4, Working with Link Controllers in a 3-DNS Sync Group .

Installing the hardware and running the Setup utility

You can find detailed instructions on installing the 3-DNS hardware in the Platform Guide 520/540 . You can find detailed instructions on running the Setup utility in Chapter 3, Using the Setup Utility , in this guide. When you have finished this part of the setup for the second system, do not make any other changes to the configuration.

Note

Making the existing controller aware of the new controller

Once you have installed the hardware and run the Setup utility on the new system, you add its configuration information to the existing 3-DNS Controller (the 3-DNS Controller that is already installed in your network).

To add the new controller to the existing controller's configuration using the Configuration utility

1. Add the second data center to the configuration.
   
   
   1. In the navigation pane, click Data Centers.
      The Data Centers screen opens.
      
      
   2. Click Add Data Center on the toolbar.
      The Add Data Centers screen opens.
      
      
   3. Add the information for the data center where you installed the new system, and click Update.
      
      
2. Add the second 3-DNS Controller to the configuration.
   
   
   1. In the navigation pane, expand the Servers item, and click 3-DNS.
      The 3-DNS List screen opens.
      
      
   2. Click Add 3-DNS on the toolbar.
      The Add New 3-DNS screen opens.
      
      
   3. Add the information for the new system, and click Update.
      
      
3. Add the new controller to the existing controller's sync group.
   
   
   1. In the navigation pane, click 3-DNS Sync.
      The System-Synchronization screen opens.
      
      
   2. Click Add to Group on the toolbar.
      The Add a 3-DNS to a Sync Group screen opens.
      
      
   3. Check the 3-DNS Controller you just defined, and click Add.
      The new controller becomes a member of the sync group of the existing controller.
      
      

You have now successfully added the new 3-DNS Controller to the existing system's configuration and sync group. The following sections describe how to run the 3dns_add script and verify the configuration.

Running the 3dns_add script

You can run the 3dns_add script on the new 3-DNS Controller either by using a remote secure shell session, or by using a monitor and keyboard connected directly to the controller.

To run the 3dns_add script

1. At the login prompt on the new controller, type root.
   
   
2. At the password prompt, type the password you configured when you ran the Setup utility.
   
   
3. To run the script, type 3dns_add at the command line.
   The script performs the following tasks:
   
   
   • Copies the existing controller's configuration to the new controller
     
     
   • Sets up SSH communications between the new controller and existing F5 devices in the network
     
     
   • Copies the existing controller's iQuery key to the new controller so communications between the controller and the big3d agents are secure
     
     
   • Gives you the option of synchronizing the named.conf file and any existing zone files

Verifying the configuration

Once the script finishes, we recommend that you verify the following aspects of your configuration:

• Verify that each 3-DNS Controller has the necessary agents and daemons running.
  
  
• Verify that any servers you configured are up and available to receive load balancing requests.
  
  
• Verify that any virtual servers you configured are up and available to respond to requests.
  
  
• Verify that any wide IPs you configured are load balancing requests as you configured them.
  
  
• Verify that any links you have configured are up and available (if applicable).
  
  

We recommend that you perform these verification tasks on the principal controller in the sync group. (Note that if you have both 3-DNS Controllers and Link Controllers in the sync group, only a 3-DNS Controller can be the principal.) The following procedures describe the verification process in detail.

To verify that each 3-DNS Controller has the necessary agents and daemons running

1. In the navigation pane, expand the Statistics item, and click 3-DNS.
   The 3-DNS Statistics screen opens.
   
   
2. In the Server and Big3d columns, make sure the status is up, which is indicated by a green ball.
   
   
3. In the E/D column, make sure the systems are enabled.
   
   
4. If the status of any of your systems is down, unknown, or unavailable, wait a few minutes and click Refresh. If status of the systems remains down, unknown, or unavailable, contact Technical Support for assistance.
   
   

To verify that the servers you configured are up

1. In the navigation pane, expand the Statistics item, and click Data Centers.
   The Data Centers Statistics screen opens.
   
   
2. In the Server column, make sure that the status of each server is up, which is indicated by a green ball.
   
   
3. If the status of any of your servers is down, unknown, or unavailable, wait a few minutes and click Refresh. If status of the servers remains down, unknown, or unavailable, contact Technical Support for assistance.
   
   

To verify that the virtual servers you configured are up

1. In the navigation pane, expand the Statistics item and click Virtual Servers.
   The Virtual Servers Statistics screen opens.
   
   
2. In the OK column, make sure that the status of each virtual server you configured is up, which is indicated by a green ball.
   
   
3. If the status of any of your virtual servers is down, unknown, or unavailable, wait a few minutes and click Refresh. If status of the virtual servers remains down, unknown, or unavailable, contact Technical Support for assistance.
   
   

To verify that the wide IPs are load balancing properly

At the command prompt, type the following command, where <IP_address> is the IP address of one of your 3-DNS Controllers, and <wideip> is the name of a wide IP in the configuration, and press Enter.

dig @<IP_address> <wideip>

If the virtual servers belonging to the wide IP appear in a pattern that reflects the load balancing mode you selected, you have successfully configured your 3-DNS Controllers. Note that you can repeat the previous procedure for each wide IP you configured, and each controller in the sync group.

Note

To verify that the links you configured are up

1. In the navigation pane, expand the Statistics item and click Links.
   The Link Statistics screen opens.
   
   
2. In the Link Summary Statistics table, in the OK column, make sure that the status of each link you configured is up, which is indicated by a green ball.
   
   
3. If the status of any of your links is down, unknown, or unavailable, wait a few minutes and click Refresh. If status of the links remains down, unknown, or unavailable, contact Technical Support for assistance.