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Manual Chapter: BIG-IQ High Availability
Manual Chapter
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About high availability configurations

To ensure that you always have access to the BIG-IP® devices under BIG-IQ® system management, install two BIG-IQ systems in a high availability (HA) configuration. Configuring for high availability is optional.

Note: Currently, a BIG-IQ HA configuration is limited to two systems, a primary and a secondary, configured as peers. Only the primary BIG-IQ system can manage BIG-IP devices.

With BIG-IQ high availability, the BIG-IQ system periodically replicates the entire BIG-IQ system state from the primary peer to the secondary to keep the two systems synchronized. This synchronization allows the secondary peer to be promoted to be the primary and take over management of the BIG-IP devices if the primary system is not fully functional. There is no automatic fail over from the primary to the secondary.

How often the primary and secondary are synchronized is configurable. In the BIG-IQ HA data replication model, this synchronization interval determines how many minutes is acceptable for the secondary peer to be out-of-date with the primary. By default, the secondary is synchronized with the primary every 10 minutes.

When you initially set up an HA pair, the systems are synchronized and you can see the configuration of what was on the primary updated on the secondary. Subsequently, when you synchronize the systems, you will not see the configuration change since the changes will be copied to the secondary system, but will not be used to update the configuration at that time. If you want to have the configuration updated on the secondary BIG-IQ system, log in to the secondary system and use the Restart with Last Update from Primary option.

If the primary BIG-IQ system in an HA cluster fails, then you need to log in to the secondary BIG-IQ system and promote it to being the primary BIG-IQ system.

If you restore a BIG-IQ system configuration using a compressed user configuration set (UCS) file, there are additional tasks you need to perform if that system is in an HA cluster. After restoring the BIG-IQ system configuration, you need to split the HA cluster that system is part of and then recreate the HA cluster.

About high availability terminology

Terminology is crucial in understanding the status of the high availability (HA) relationship. The following list defines some important terms used in HA configurations.

primary
The node you are logged in to when establishing the pair is deemed the primary node; the system added is deemed the secondary node.
secondary
Any node added to the configuration is deemed the secondary node. Currently, the BIG-IQ ® system supports a 2-node pairing.
pairing
Adding a secondary node to the BIG-IQ system configuration is called pairing. During the pairing process, the primary BIG-IQ system discovers information on the secondary node. When it is finished discovering the secondary system, the primary node creates a storage checkpoint of the current state of the storage on the primary node. When complete, the storage checkpoint is copied to the secondary node, and the secondary node then assumes its new role.
Note: Data is always transferred from the primary node to the secondary node. Storage configuration data is not copied from the secondary node to the primary node, so configuration edits should never be made on the secondary node.
cluster
A synonym for a high availability configuration is cluster. A cluster comprises at least two BIG-IQ systems (fully installed and licensed, and running the same version of software), and is configured in a high availability relationship through the BIG-IQ > BIG-IQ Systems > Properties screen.

Pairing BIG-IQ systems for high availability

Before you can configure BIG-IQ® systems for high availability (HA), you must have two licensed BIG-IQ systems, installed with the required system components. For the high-availability pair to synchronize properly, each must be running the same BIG-IQ version, and the clocks on each system must be synchronized within 60 seconds, and remain synchronized. Prior to establishing the pair, examine the NTP settings at the BIG-IQ system level and the current system time value.
You pair two BIG-IQ systems to create a high availability cluster.
  1. Select the BIG-IQ system to act as the primary in the HA cluster.
    The configuration of this system is the one that will be preserved.
  2. Log in to the selected BIG-IQ system, using administrator credentials.
  3. From the BIG-IQ main list, select System.
  4. Hover over the HA Peer Group, click the gear icon and select Add Device.
  5. In the New Device screen, complete the following settings:
    These settings define the secondary peer in the HA cluster.
    1. In the IP Address field, type the self IP address.
    2. In the User name field, type the administrative user name.
    3. For Password, type the administrative password.
    4. In the Root Password field, type the root password.
    5. From the Group list, select HA Peer Group.
  6. Click Add.
When you expand the HA Peer Group, you see both nodes of the HA cluster. The localhost node is the system you are on.

Splitting a high availability pair

To change or reconfigure peers that are in a BIG-IQ® high availability (HA) pair, you must first delete the HA relationship.
  1. Log in to the primary BIG-IQ system, using administrator credentials.
  2. From the BIG-IQ list, select System.
  3. On the BIG-IQ Systems panel, expand the HA Peer Group.
  4. Hover over the secondary peer and when the gear icon appears, click it and select Properties to open the screen.
  5. In the expanded screen, click Remove.
The pair is now split. Consult the status line at the top of the screen for the status. Both nodes display a status of Standalone.

Manually synchronizing the BIG-IQ systems

The BIG-IQ® systems in an HA Peer Group are synchronized automatically. If you need the systems to be synchronized immediately, you can manually synchronize the systems and view information about the synchronization using the properties screen of the primary BIG-IQ system.
  1. Log in to the primary BIG-IQ system, using administrator credentials.
  2. From the BIG-IQ main list, select System.
  3. On the BIG-IQ Systems panel, expand the HA Peer Group.
  4. Hover over the primary BIG-IQ system and when the gear icon appears, click it and select Properties to open the screen.
  5. In the expanded screen, on the Properties tab, review the information in the HA Sync Interval setting.
    • The number displayed at the top field of this setting is the number of minutes to wait before synchronizing the BIG-IQ systems. By default, this number is 10, but it can be any whole number from 5 to 60.
    • Next displays the time the BIG-IQ systems will next be synchronized.
    • The area below the Next line lists whether the synchronization succeeded or failed. If it succeeded, the time when the synchronization occurred is listed. If it failed, an error message is listed.
  6. Click Sync Now to cause the BIG-IQ systems to be synchronized immediately.
The configuration of the primary BIG-IQ system is copied to the secondary BIG-IQ system. You do not see these changes on the secondary system until that system is promoted to being the primary system, or until the secondary system is updated and restarted using the Restart with Last Update from Primary option available on the secondary BIG-IQ system.

Changing how often BIG-IQ systems are synchronized

The BIG-IQ® systems in an HA Peer Group are synchronized automatically at a regular interval. If you need to lengthen or shorten the synchronization interval, you can change it using the properties screen of the primary BIG-IQ system.
  1. Log in to the primary BIG-IQ system, using administrator credentials.
  2. From the BIG-IQ main list, select System.
  3. On the BIG-IQ Systems panel header, expand the HA Peer Group.
  4. Hover over the primary BIG-IQ system, in this case labeled as localhost, and when the gear icon appears, click it and select Properties to open the screen.
  5. In the screen on the Properties tab, in the HA Sync Interval settings, review the number displayed, and change it if needed.
    This value is the number of minutes to wait before synchronizing the BIG-IQ systems. You can change this value to a whole number from 5 to 60.
  6. Click Save to save your changes.

Promoting the secondary from the primary BIG-IQ system

You may want to make the secondary BIG-IQ® system the primary system, such as when the current primary system is having system difficulties. You can promote the secondary BIG-IQ system to be the primary BIG-IQ system while logged on to the primary or the secondary BIG-IQ system. This task describes how to promote the secondary BIG-IQ system while on the primary BIG-IQ system.
  1. Log in to the primary BIG-IQ system, using administrator credentials.
  2. From the BIG-IQ main list, select System.
  3. On the BIG-IQ Systems panel, expand the HA Peer Group.
  4. Hover over the secondary BIG-IQ system name, and when the gear icon appears, click it and select Properties to open the screen.
  5. In the expanded screen on the Properties tab, in the Actions on this Device setting, click Promote this Device to Primary.
The secondary BIG-IQ system is synchronized with the primary BIG-IQ system and promoted to being the primary BIG-IQ system. The primary system assumes the role of the secondary.

Promoting the secondary from the secondary BIG-IQ system

You may want to make the secondary BIG-IQ® system the primary system, such as when the current primary system is having system difficulties. You can promote the secondary BIG-IQ® system to be the primary BIG-IQ system while logged on to the primary or secondary BIG-IQ system. This task describes how to promote the secondary BIG-IQ system while on the secondary BIG-IQ system.
  1. Log in to the secondary BIG-IQ system, using administrator credentials.
  2. From the BIG-IQ main list, select System.
  3. On the BIG-IQ Systems panel, expand the HA Peer Group.
  4. Hover over the secondary BIG-IQ system, in this list labeled as localhost, and when the gear icon appears, click it and select Properties to open the screen.
  5. In the expanded screen on the Properties tab, in the Actions on this Device setting, click Promote this Device to Primary.
The secondary BIG-IQ system is synchronized with the primary BIG-IQ system and promoted to being the primary BIG-IQ system. The primary system assumes the role of the secondary.
If the primary system goes down, the secondary detects this and displays the Peer Down status at the top of the screen. When you click Promote this Device to Primary in this scenario, the secondary becomes a standalone system and restarts. At this point, the HA cluster is broken.
Note: If the former primary peer comes back online, it still considers itself a primary in an HA cluster, so you need to log in to that system and break the HA pair, resulting in it becoming a standalone system.

Updating the secondary BIG-IQ system with changes from the primary

Because configuration changes from the primary BIG-IQ® system are not automatically used to update the configuration of the secondary BIG-IQ system, you may want to periodically update the configuration of the secondary BIG-IQ system manually.
  1. Log in to the secondary BIG-IQ system, using administrator credentials.
  2. From the BIG-IQ main list, select System.
  3. On the BIG-IQ Systems panel, expand HA Peer Group.
  4. Hover over the secondary BIG-IQ system, in this case, localhost, and when the gear icon appears, click it and select Properties to open the screen.
  5. In the expanded screen on the Properties tab, in the Actions on this Device setting, click Restart with Last Update from Primary.

The secondary system applies the last set of configuration changes it received from the primary system, and then restarts.

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