Machine groups are a method in which machines in a server cluster can be allocated to one or more named sets of machines. These groups can then utilised by MessageLogger, WebConsole or your own custom utilities. Note that the use of groups is optional.

Machine groups are created by placing a category [Groups] in the /etc/bwmachined.conf file, with entries containing the machine groups that the machine is assigned to. For example, two machines in the BigWorld office are allocated separately to the client and server team for each teams testing purposes during the week, but also belong to an office wide cluster group that can be used for larger scale weekend testing.

Machine A's /etc/bwmachined.conf:

[Groups]
bw_client
bw_weekend_tests

Machine B's /etc/bwmachined.conf:

[Groups]
bw_server
bw_weekend_tests

In WebConsole when starting a new server the option "On a group of machines" can then be chosen and the server will start across all machines contained in the selected group. For information on how to use Machine Groups with MessageLogger to assist scalability within a production environment please refer to the Production Scalability.

Starting a server using a machine group

The global configuration file /etc/bwmachined.conf can contain entries for user defined categories, and a list of items pertaining to it. The syntax for these categories is as follows (* meaning 0 or more occurrences):

*[category]
*item

Server tools can query BWMachined to find the items associated with user categories. Categories may be used by future tools or customer-created tools. The following sections outline some usages of categories currently in use by BigWorld.