Novell SUSE LINUX ENTERPRISE SERVER 10 SP2 HEARTBEAT Manual page 18

to all of its members. It performs this task based on the information it gets from the
Heartbeat layer. The logic that takes care of this task is contained in the Cluster Con-
sensus Membership service, which provides an organized cluster topology overview
(node-wise) to cluster components that are the higher layers.
Resource Allocation Layer
The third layer is the resource allocation layer. This layer is the most complex, and
consists of the following components:
Cluster Resource Manager
Every action taken in the resource allocation layer passes through the Cluster Re-
source Manager. If any other components of the resource allocation layer, or other
components which are in a higher layer need to communicate, they do so through
the local Cluster Resource Manager.
On every node, the Cluster Resource Manager maintains the Cluster Information
Base, or CIB (see
Manager in the cluster is elected as the Designated Coordinator (DC), meaning that
it has the master CIB. All other CIBs in the cluster are a replicas of the master CIB.
Normal read and write operations on the CIB are serialized through the master CIB.
The DC is the only entity in the cluster that can decide that a cluster-wide change
needs to be performed, such as fencing a node or moving resources around.
Cluster Information Base
The Cluster Information Base or CIB is an in-memory XML representation of the
entire cluster configuration and status, including node membership, resources,
constraints, etc. There is one master CIB in the cluster, maintained by the DC. All
the other nodes contain a CIB replica. If an administrator wants to manipulate the
cluster's behavior, he can use either the cibadmin command line tool or the
Heartbeat GUI tool.
NOTE: Usage of Heartbeat GUI Tool and cibadmin
The Heartbeat GUI tool can be used from any machine with a connection
to the cluster. The cibadmin command must be used on a cluster node,
and is not restricted to only the DC node.
10 Heartbeat
Cluster Information Base (page 10) below). One Cluster Resource