Defining machines

Machines represent physical computers or servers that can have multiple WebLogic instances. On every machine you want to use the Node Manager facilities, you need to start a Node Manager instance.

Machines are also important to define replication groups for HTTP sessions when using cluster and backup instances for JMS servers, singleton services, and other critical WebLogic services.

Here's a representation of a cluster that spans over two machines:

For the examples we're going to run in this book, only one physical machine is enough. In fact, it can be your own computer or laptop since the Node Manager process ensures negligible memory and CPU consumption and with 8 GB of RAM, you can easily run at least two WebLogic Managed Servers simultaneously. Let's set up our machine:

1. Open the WebLogic console at http://localhost:7001/console.

2. In the left menu, expand the Environment section and then click on Machines.

3. Click on the New button and fill the information using these values...