Cluster management software

Cluster management software maximizes the work that a cluster of computers can perform. A cluster manager balances workload to reduce bottlenecks, monitors the health of the elements of the cluster, and manages failover when an element fails. A cluster manager can also help a system administrator to perform administration tasks on elements in the cluster (by rerouting workload off of a computer that needs to be serviced, for example.)

Elements of a cluster

To function properly, the cluster manager must be aware of many details related to the elements of the cluster, and the cluster manager must be aware of the relationships between the elements of the cluster.

Here are some examples of cluster elements of which the cluster manager must be aware:
  • Physical or virtual computers, machines, or devices in the cluster (in a cluster context, these are referred to as cluster nodes)
  • Networks that connect the cluster nodes
  • Network interfaces cards that connect the cluster nodes to the networks
  • IP addresses of cluster nodes
  • Virtual or services IP addresses
Here are some examples of relationships of which the cluster manager must be aware:
  • Pairs of cluster nodes that have the same software installed and can failover for one another
  • Networks that have the same properties and can be used to failover for one another
  • The cluster node to which a virtual IP address is currently associated

Adding or modifying elements of your cluster

To make the cluster manager aware of the elements of your cluster and the relationships between those elements, a system administrator must register the elements with the cluster manager. If a system administrator makes a change to the elements of the cluster, the administrator must communicate that change to the cluster manager. Cluster managers have interfaces to help with these tasks.

Cluster administration is challenging because there is an enormous variety of possible cluster elements. An administrator must be an expert in the hardware and operating systems of the cluster nodes, networking protocols and configuration, and the software installed on the cluster nodes such as database software. Registering the elements of the cluster with the cluster management software, or updating the cluster manager after a system change, can be complex and time consuming.

Using db2haicu to add or modify elements of your cluster

In a Db2® database solution, you can use the Db2 high availability instance configuration utility (db2haicu) to register the elements of your cluster with the cluster manager, and to update the cluster manager after making an administrative change to your cluster. Using db2haicu simplifies these tasks because once you know the model that db2haicu uses to encapsulate the elements of your cluster and the relationships between those elements, you do not need to be an expert in the idiosyncrasies of your hardware, operating systems, and cluster manager interface to perform the tasks.