Dynamic clusters

A dynamic cluster is a server cluster that uses weights and workload management to balance the workloads of its cluster members dynamically, based on performance information that is collected from the cluster members. Dynamic clusters enable application server virtualization.

A dynamic cluster is an application deployment target that can expand and contract depending on the workload in the environment. Dynamic clusters work with autonomic managers, including the application placement controller and the dynamic workload manager to maximize the use of the computing resources. Dynamic clusters are required for many of the Intelligent Management autonomic functions, including high availability and service policies.

For complete life-cycle management servers, the product controls the creation and deletion of server instances and can start and stop servers. For assisted life-cycle management servers, the product can control the state of servers by stopping and starting servers from a pool of predefined server instances.

Dynamic cluster membership

Two options exist for adding members to a dynamic cluster: automatically define cluster members with rules or manually define cluster members.

Server templates

A server template is a copy of a server configuration that can be used as a starting point when a server is added to the dynamic cluster. Predefined templates exist for different middleware server types. We can also define our own server templates.

Dynamic cluster server templates

After creating a dynamic cluster, the dynamic cluster server template defines the properties for all of the members in the dynamic cluster.

When you make a change to a dynamic cluster server template, this will overwrite any changes you made that are unique to an individual member of that cluster.gotcha

Cluster instances

We can control the creation and management of cluster instances for the dynamic cluster. These options include:

Operating modes

Dynamic clusters act differently depending on the operating mode. Choose one of the following options for mode of operation:

Important: To use dynamic application placement, click automatic or supervised as the mode of operation.

If we are using manual mode for the autonomic request flow manager (ARFM) on either the cell level or deployment target level, then you also must put the dynamic clusters in manual mode. We can also use static clusters when ARFM is in manual mode for the cell or deployment target. If ARFM is in automatic mode, we can use any of the operating modes for the cluster.

Related concepts

  • Dynamic cluster isolation
  • Dynamic application placement

    Related tasks

  • Configure vertical stacking

  • Intelligent Management: static clusters versus dynamic clusters