Chapter 8 Using System Groups to Standardize Configurations

Specifying groups of systems provides a way to make changes to many systems at the same time, for example to apply errata, update packages, or change channel subscriptions. System groups allow you to standardize software configurations so that member systems have consistent release and patch levels. In large-scale deployments, using system groups helps to automate system management tasks.

You can create a system group on the System Groups page of the web interface or by using the group_create and add_systems subcommands of spacecmd.

For example, create the group grp-prod-db-mke and add all systems that currently subscribe to the channel ol7u1-x86_64-20150807 to that group:

spacecmd {SSM:0}> group_create grp-pdb "Production DB Server Group"
spacecmd {SSM:0}> add_systems grp-pdb channel:ol7u1-x86_64-20150807

To change the base channel for all servers in a system group, you can specify the group name to spacecmd, as shown in the following example:

spacecmd {SSM:0}> system_setbasechannel group:grp-pdb ol7-x86_64-QAr2-base

You can use a command such as this to change the channel subscriptions for many systems at the same time, for example, to promote all systems that currently subscribe to test channels to subscribe to production channels instead. You can also perform Spacewalk management operations on a single system group or on the union or intersection of two or more system groups.