Database Objects Fields and Attributes

Various ICE ClusterWare™ database objects (nodes, boot configurations, image configurations, administrators, attributes, etc.) each carry with them detailed descriptors called fields. Each field consists of a name-value pair and is relevant for its database object type. Fields are predefined by the ClusterWare platform. The cluster administrator uses the update action to change a field value.

For instance, a compute node object for each node has fields mac with the node's MAC address, name with the node's alphanumeric name, and power_uri with a value denoting how to communicate via ipmi to that node. For example, the command scyld-nodectl -i n0 ls -l displays all the defined fields' name-value pairs for node n0.

Compute node and Attribute Groups object types have special fields called attributes, where an attribute is a collection of one or more attribute name-value pairs. Attribute names that begin with an underscore "_" are called reserved attributes or system attributes. The cluster administrator uses the set action to change an attribute value. See Reserved Attributes for details.

Additional attributes can be added by a cluster administrator as desired, each with a custom name and value defined by the administrator. Any script on a compute node can access the local file /etc/clusterware/attributes.ini and find that node's attributes. On the node there are helper functions in /opt/scyld/clusterware-node/functions.sh for reading attributes, specifically the function attribute_value.