Creating a user-defined node class for Transparent cloud tiering or Cloud data sharing

This topic provides step-by-step instructions for creating and configuring the required node class to specify which IBM Spectrum Scale™ nodes will be used for cloud services.

Note: You need to run this command only once on any node on the IBM Spectrum Scale cluster.

You can install cloud services on a maximum of 4 nodes (any combination of NSD or CES nodes) on the IBM Spectrum Scale cluster. Before you install cloud services, you need to create a node class specifying the IP addresses (or fully qualified host names) of the nodes where the server packages are going to be installed. You can use any host name that the -N option accepts. For details, see mmcrnodeclass command in IBM Spectrum Scale: Command and Programming Reference.

You can enable and manage independent groups of cloud services nodes in different node classes for use with different network configurations per node class. Nodes are mutually exclusive to each node class and cannot be shared with another node class that has cloud services nodes. For example, the node class TCTNodeClass1 has node1 and node2 and the node class TCTNodeClass2 has node3 and node 4. All nodes are cloud services enabled nodes. In this case, the node class TCTNodeClass2 cannot enable node1 as a cloud services node under the TCTNodeClass2 node class because it is already marked for cloud services usage under the TCTNodeClass1 node class, and so on. Additionally, each group of cloud services enabled nodes under a node class cannot share the same file system with cloud services enabled nodes from a different node class. And each cloud services enabled node under a node class is limited to use only 1 common file system with each node in that node class. Therefore, you must manage each group of cloud services nodes within a node class as a pool of nodes requiring a single common file system.

Note: It is recommended that you set up at least 2 nodes so that you have good availability for the service if a node were to go down. Ensure to use the GPFS™ cluster IP address that gets displayed when you run the mmlscluster command.

To create a node class, issue a command according to this syntax:

mmcrnodeclass ClassName -N {Node[,Node...] | NodeFile | NodeClass}

For example, to create a node class called TCTNodeClass by using three nodes 10.10.10.10, 11.11.11.11, and 12.12.12.12, issue this command:

mmcrnodeclass TCTNodeClass -N 10.10.10.10,11.11.11.11,12.12.12.12

To verify that the node class is created, issue this command:

mmnlsnodeclass

The system displays output similar to this:

Node Class Name Members
--------------------- -----------------------------------------------------------
TCTNodeClass node10,node11,node12

For more information on the usage and the other options available in the mmcrnodeclass command, see mmcrnodeclass command

Next step: Installing cloud services on IBM Spectrum Scale nodes