In the HA Configuration section (Settings and Configuration > HA Configuration), you can configure two Kemp 360 Central instances into a master-slave High Availability (HA) configuration as follows:

  • Both HA units are active in terms of enabling you to make changes to Kemp 360 Central and managed device configuration, synchronization of data, and gathering syslog output from managed devices.
Note: Only network tree and device configuration is synchronized. Nothing in the Global Repository (for example, backups, templates, and firmware) is synchronized.
  • Only the master unit generates statistics and communicates these to the slave unit periodically.
  • Scheduled actions can be configured on either unit and are communicated to the other unit, but they are executed only by the current master unit.

Under normal operating conditions the master processes the scheduled tasks and the slave synchronizes repository files from the master. If the slave fails, nothing happens, but when it recovers, it checks if the master is up. If the master is not up, the slave becomes the master. If the master is up, the slave synchronizes repository files from the master.

Note: When configuring two Kemp 360 Central instances into HA mode, both units must have at least one network defined for the initial synchronization to complete successfully. When the initial synchronization is complete, changes are propagated in both directions.

Before configuring two Kemp 360 Central instances into HA mode, decide which unit you want to be the Preferred Master. The Preferred Master always assumes the master role in the HA configuration when it is available. The other unit becomes the Preferred Slave; should the Preferred Master become unavailable, the Preferred Slave takes over from the master and returns control to the Preferred Master once it is available again.

CAUTION: LoadMaster profiles and target environments are not currently synchronized between Kemp 360 Central HA units.

To configure two Kemp 360 Central instances into HA mode, perform the following steps:

Note: If the Kemp 360 Central units that you are configuring into an HA pair already have configurations on them, determine which of the configurations you want to keep (if any). The system that has the configuration you want to keep should be configured first, so that it goes into Master mode. The configuration on the other unit will be overwritten when it assumes the Slave mode.
  1. Open the Kemp 360 Central UI of both units that you want to configure into HA mode (Settings and Configuration > HA Configuration).
  2. On the UI of the unit that you want to make the Slave, copy the HA Key for this Peer from the HA Configuration section.
  3. On the UI of the unit you want to become the Master:
    1. Paste the HA Key you copied in the previous step into the HA Key for the Other Peer field.
    2. Select the Preferred Master check box.
    3. Type the IP address of the Slave unit into the IP Address for the Other Peer field.
    4. Click Apply.
    Note: Wait until the Our State field in the HA Status section indicates that this unit has assumed the Master state before moving on to the next step. This is critical to ensuring that both units assume the desired state and the intended configuration is propagated. This may take a few minutes.
  4. On the UI of the unit that has just entered the Master state, copy the HA Key for this Peer from the HA Configuration section.
  5. On the UI of the unit you want to become the Slave:
    1. Paste the HA Key you copied in the previous step into the HA Key for the Other Peer field.
    2. Type the IP address of the Slave unit into the IP Address for the Other Peer field.
    3. Click Apply.
Note: Wait until the Our State field in the HA Status accordion indicates that this unit has assumed the Slave state. This may take a few minutes.

The HA Configuration is complete once the HA status accordion shows that one unit is in the Master state, one unit is in the Slave state, and that heartbeats are being actively exchanged between the two HA units.

Note: Both Kemp 360 Central HA units try to contact one another every 30 seconds; this is called a heartbeat and is the method by which the two units determine when a fail over should occur. Since these heartbeats occur every 30 seconds, there can be up to a 30-second delay between the time that the current master HA unit becomes unavailable and the time that the current slave becomes aware of the outage and attempts to take over the master role.
Note: The sequence number is mainly used for debugging and should match the sequence number on the peer. This is useful to check if the pairs are working correctly.

If the master goes down, this can be viewed in the HA Status panel after 30 seconds. If you click Refresh, you see the error and the number of heartbeats that were missed. The slave now becomes the master. Once the original master comes back online, the system reverts to the original master if you selected the Preferred Master check box when you configured it.

Note: You can configure a LoadMaster HA pair within a Kemp 360 Central HA pair.