Weblogic Dynamic Cluster configuration

This is a new feature available in Weblogic 12c (12.1.2).

Dynamic cluster contains one or more dynamic servers. It allows you to add a new server dynamically at peak loads.  This would eliminate the need of adding the managed server manually to a cluster.  The businesses can define number of servers that needs to be added dynamically anticipating the peak loads.

The concept of dynamic cluster is based on a single shared server template.

For further reading on server template please refer the below post.

Prerequisites:

1. Configured machine .

 

You can create the setup in two ways.

1. From Administration console
2. Using WLST

 

I. Using Administration console:

1. Login into the administration console  — >  Cluster  — > Click on new — > Select Dynamic Cluster from the drop down.

 

 

2. Select the messaging mode and define number of servers you would need at the peak load.

You can either create a new server template or use an already existing one.

 

 

3. Associate dynamic servers with machines.

Note: Associating dynamic servers with machines is essential if you intend to use the Node Manager and the Administration Console (or WLST) to start servers.

 

 

 

4. Specify Listen port bindings:

You would need to define port bindings for only one dynamic server, and each subsequent server will be given an incremental port.

 

 

This would create a server template based on the dynamic cluster configuration, which can be reused.

 

 

 

II . Using WLST:

You can use the below WLST to create a dynamic cluster.

# This example demonstrates the WLST commands needed to create a dynamic cluster
# (dynamic-cluster). The dynamic cluster utilizes a server template    
# dynamic-cluster-server-template. To keep this example simple, error handling
# was omitted.
#

connect()

edit()

startEdit()

#
# Create the server template for the dynamic servers and set the attributes for
# the dynamic servers. Setting the cluster is not required.
#

dynamicServerTemplate=cmo.createServerTemplate("dynamic-cluster-server-template")

dynamicServerTemplate.setAcceptBacklog(2000)

dynamicServerTemplate.setAutoRestart(true)

dynamicServerTemplate.setRestartMax(10)

dynamicServerTemplate.setStartupTimeout(600)

#
# Create the dynamic cluster and set the dynamic servers.
#

dynCluster=cmo.createCluster("dynamic-cluster")

dynServers=dynCluster.getDynamicServers()

dynServers.setMaximumDynamicServerCount(10)

dynServers.setServerTemplate(dynamicServerTemplate)

#
# Dynamic server names will be dynamic-server-1, dynamic-server-2, ...,
# dynamic-server-10.
#

dynServers.setServerNamePrefix("dynamic-server-")

#
# Listen ports and machines assignments will be calculated. Using a round-robin
# algorithm, servers will be assigned to machines with names that start with
# dyn-machine.
#

dynServers.setCalculatedMachineNames(true)
dynServers.setMachineNameMatchExpression("dyn-machine*")

#
# activate the changes
#
activate()

 

 

Further  reading:

http://docs.oracle.com/middleware/1212/wls/CLUST/dynamic_clusters.htm#CLUST678

Cheers,

Wonders Team 🙂