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Manual Chapter : Adding a new BIG-IP DNS to a BIG-IP DNS Synchronization Group

Applies To:

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BIG-IP LTM

  • 17.0.0, 16.1.2, 16.1.1, 16.1.0, 16.0.1, 16.0.0

BIG-IP DNS

  • 17.0.0, 16.1.2, 16.1.1, 16.1.0, 16.0.1, 16.0.0
Manual Chapter

Adding a new BIG-IP DNS to a BIG-IP DNS Synchronization Group

Overview: Adding a BIG-IP DNS system to a BIG-IP DNS synchronization group

You can configure BIG-IP DNS (formerly (GTM)) systems in collections called BIG-IP DNS synchronization groups. All BIG-IP DNS systems in the same
BIG-IP DNS synchronization group
 have the same rank, exchange heartbeat messages, and share probing responsibility.
Configuration changes to one device in a BIG-IP DNS synchronization group are synchronized incrementally across the devices in the group. That is, only the data that has changed on a BIG-IP DNS device is synchronized to the other devices in the group. Although incremental synchronization is the default behavior, if an incremental synchronization fails, the system automatically performs a full configuration synchronization.
BIG-IP DNS systems in a BIG-IP DNS synchronization group
BIG-IP DNS systems in a synchronization group
When you add a BIG-IP DNS system to a network that contains older BIG-IP DNS systems, the devices can exchange heartbeat messages, even though the BIG-IP software versions are different. However, to add BIG-IP DNS to a configuration synchronization group, you must run the
gtm_add
 script.

Task summary

When adding BIG-IP® DNS to a network that already contains BIG-IP DNS systems in a synchronization group, perform the following tasks only on the existing DNS system that you want to later acquire the configuration settings from by running the gtm_add script on the new DNS system.
Do not perform any data center or server DNS configuration on the new system, the configuration is imported from the existing configuration and any configuration on the new device will be overwritten.

Enabling synchronization on the existing BIG-IP DNS

Ensure that BIG-IP DNS references your NTP servers.
Decide to which BIG-IP DNS synchronization group you want to add the BIG-IP DNS system. Make certain that at least one previously-configured BIG-IP DNS belongs to that BIG-IP DNS synchronization group.
Enable synchronization on the system to ensure that the BIG-IP DNS system that is already installed on your network can share configuration changes with other BIG-IP DNS systems that you add to the BIG-IP DNS synchronization group.
  1. On the Main tab, click
    DNS
    Settings
    GSLB
    General
    .
    The General configuration screen opens.
  2. Select the
    Synchronize
     check box.
  3. In the
    Group Name
     field, type the name of the synchronization group to which you want this system to belong.
  4. In the
    Time Tolerance
     field, type the maximum number of seconds allowed between the time settings on this system and the other systems in the synchronization group.
    The lower the value, the more often this system makes a log entry indicating that there is a difference.
    If you are using NTP, leave this setting at the default value of
    10
    . In the event that NTP fails, the system uses the time_tolerance variable to maintain synchronization.
  5. Click
    Update
    .
When a change is made on one BIG-IP DNS system in the BIG-IP DNS synchronization group, that change is automatically synchronized to the other systems in the group.

Creating a data center on the existing BIG-IP DNS

Create a data center on the existing DNS system to represent the location where the new BIG-IP DNS system resides.
  1. On the Main tab, click
    DNS
    GSLB
    Data Centers
    .
    The Data Center List screen opens.
  2. Click
    Create
    .
    The New Data Center screen opens.
  3. In the
    Name
     field, type a name to identify the data center.
    The data center name is limited to 63 characters.
  4. In the
    Location
     field, type the geographic location of the data center.
  5. In the
    Contact
     field, type the name of either the administrator or the department that manages the data center.
  6. From the
    Prober Preference
     list, select the preferred type of prober(s).
    Inside Data Center
    By default, select probers inside the data center.
    Outside Data Center
    Select probers outside the data center.
    Specific Prober Pool
    Select one of the Probers from the drop-down list. When you want to assign a Prober pool at the data center level.
    Note
    : Prober pools are not used by the bigip monitor.
  7. From the
    Prober Fallback
     list, select the type of prober(s) to use if insufficient numbers of the preferred type are available.
    Any Available
    By default, select any available prober.
    Inside Data Center
    Select probers inside the data center.
    Outside Data Center
    Select probers outside the data center.
    None
    No fallback probers are selected. Prober fallback is disabled.
    Specific Prober Pool
    Select one of the Probers from the drop-down list. When you want to assign a Prober pool at the data center level.
  8. From the
    State
     list, select
    Enabled
     or
    Disabled
    .
    The default is
    Enabled
    , which specifies that the data center and its resources are available for load balancing.
  9. Click
    Finished
    .

Defining a server on the existing BIG-IP DNS

You must ensure that a data center where the new DNS system resides is available in the configuration of the existing BIG-IP DNS before you start this task.
You define a new server, on the existing BIG-IP DNS system, to represent the new BIG-IP DNS system.
  1. On the Main tab, click
    DNS
    GSLB
    Servers
    .
    The Server List screen opens.
  2. Click
    Create
    .
    The New Server screen opens.
  3. In the
    Name
     field, type a name for the server.
    Server names are limited to 63 characters.
  4. From the
    Product
     list, select
    BIG-IP System
    .
  5. From the
    Data Center
     list, select the data center where the server resides.
  6. From the
    Prober Preference
     list, select the preferred type of prober(s).
    Inherit From Data Center
    By default, a server inherits the prober preference selection assigned to the data center in which the server resides.
    Inside Data Center
    A server selects the probers from inside the data center where the server resides.
    Outside Data Center
    A server selects the probers from outside the data center where the server resides.
    Specific Prober Pool
    Select one of the Prober pools from the drop-down list. When assigning the Prober pool at the server level.
    Note
    :
    Prober pools are not used by the bigip monitor.
  7. From the
    Prober Fallback
     list, select the type of prober(s) to be used if insufficient numbers of the preferred type are available.
    Inherit From Data Center
    By default, a server inherits the prober fallback selection assigned to the data center in which the server resides.
    Any Available
    For selecting any available prober.
    Inside Data Center
    A server selects probers from inside the data center where the server resides.
    Outside Data Center
    A server selects probers from outside the data center where the server resides.
    None
    No fallback probers are selected. Prober fallback is disabled.
    Specific Prober Pool
    Select one of the probers from the list When you want to assign a prober pool at the server level.
  8. From the
    State
     list, select
    Enabled
    .
  9. For the
    BIG-IP System Devices
     setting, click
    Add
     to add a device (server).
    1. Type a name in the
      Device Name
       field.
    2. Type an external (public) non-floating IP address in the
      Address
       field.
    3. If you use NAT, type an internal (private) IP address in the
      Translation
       field, and then click
      Add
      .
    4. Click
      Add
      .
    5. Click
      OK
      .
  10. From the
    Configuration
     list, select
    Advanced
    .
    Additional controls display on the screen.
  11. In the
    Health Monitors
     setting, assign the
    bigip
     monitor to the server by moving it from the
    Available
     list to the
    Selected
     list.
  12. From the
    Availability Requirements
     list, select an option and enter any required values.
    All Health Monitors
    By default, specifies that all of the selected health monitors must be successful before the server is considered up (available).
    At Least
    The minimum number of selected health monitors that must be successful before the server is considered up.
    Require
    The minimum number of successful probes required from the total number of probers requested.
  13. From the
    Virtual Server Discovery
     list, select how you want virtual servers to be added to the system.
    If the virtual server IP address translation feature is going to be used, then BIG-IP DNS will automatically disable Virtual Server Discovery for the given server object globally.
    Disabled
    The system does not use the discovery feature to automatically add virtual servers. This is the default value. Use this option for a standalone BIG-IP DNS system or for a BIG-IP DNS/LTM combo system when you plan to manually add virtual servers to the system, or if your network uses multiple route domains.
    Enabled
    The system uses the discovery feature to automatically add and delete virtual servers. Use this option for a BIG-IP DNS/LTM combo system when you want the BIG-IP DNS system to discover LTM virtual servers.
    Enabled (No Delete)
    The system uses the discovery feature to automatically add virtual servers and does not delete any virtual servers that already exist in the configuration. Use this option for a BIG-IP DNS/LTM combo system when you want the BIG-IP DNS system to discover LTM virtual servers.
  14. In the
    Virtual Server List
     setting, if you selected
    Disabled
     from the
    Virtual Server Discovery
     list, specify the virtual servers that are resources on this server.
    1. In the
      Name
       field, type the name of the virtual server.
    2. In the
      Address
       field, type the IP address of the virtual server.
    3. From the
      Service Port
       list, select the port the server uses.
    4. Click
      Add
      .
  15. Click
    Finished
    .
    The
    gtmd
     process on each BIG-IP DNS system will attempt to establish an iQuery connection over port
    4353
     with each self IP address defined on each server in the BIG-IP DNS configuration of type BIG-IP. Allow port
    4353
     in your port lockdown settings for iQuery to work.
    The Server List screen opens displaying the new server in the list.
The status of the newly defined BIG-IP DNS system is Unknown, because you have not yet run the
gtm_add
 script.

Running the gtm_add script

Before you start this task, you must determine the self IP address of a DNS system in the BIG-IP DNS synchronization group to which you want to add another BIG-IP DNS.
You run the
gtm_add
 script on the BIG-IP DNS system you are adding to your network to acquire the configuration settings from a BIG-IP DNS system that is already installed on your network. For additional information about running the script, see SOL13312 on AskF5.com (
www.askf5.com
).
The BIG-IP DNS and other BIG-IP systems must have TCP port
22
 open between the systems for the script to work. You must perform this task from the command-line interface.
  1. Log in as
    root
     to the BIG-IP DNS system you are adding to your network.
  2. Run this command to access
    tmsh
    .
    tmsh
  3. Run this command to run the
    gtm_add
     script
    run gtm gtm_add
    1. Press the
      y
       key to start the
      gtm_add
       script.
    2. Type the IP address of the BIG-IP DNS system in the synchronization group to which you are adding this BIG-IP DNS system.
    3. Press
      Enter
      .
    4. If prompted, type the
      root
       password.
    5. Press
      Enter
      .
The BIG-IP DNS system you are installing on your network acquires the configuration of the BIG-IP DNS system already installed on your network.

Implementation result

The new BIG-IP DNS system that you added to the network is a part of a BIG-IP DNS synchronization group. Changes you make to any system in the BIG-IP DNS synchronization group are automatically propagated to all other BIG-IP DNS systems in the group.
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