Compute Node Initialization Scripts

All compute node images should include the clusterware-node package. This package includes systemd services used for periodically reporting node status back to the head node as well as initialization scripts run as the node is booting.

At the end of the boot process described in Boot Configurations, the mount_rootfs script hands control of the machine over to the standard operating system initialization scripts when it switches to the newly mounted root. Shortly after networking is established on the booting node, it contacts the parent head node, the compute node begins periodic pushes of status information to the parent, which stores that information in the ICE ClusterWare™ database. The first data push includes detected hardware information, while subsequent data only contains the more ephemeral node status information. With each status update the node also retrieves its attribute list and stores this list as an INI file at /opt/scyld/clusterware-node/etc/attributes.ini. Code running on the compute node can use the contents of this file to customize the node configuration. A simple attributes.ini file:

[Node]
UID = c1bf15749d724105bce9e07a3d79cb69

[Attributes]
_boot_config = DefaultBoot

The [Node] section will include node-specific details, while the [Attributes] section contains the node attributes as determined from the node's groups using the process described in Node Attributes. The clusterware-node package also contains a symlink at /etc/clusterware pointing to /opt/scyld/clusterware-node/etc/.

Shortly after the first status push, a series of shell scripts are executed on the node to perform ClusterWare-specific node initialization. These scripts are linked in /opt/scyld/clusterware-node/scripts-enabled and located in /opt/scyld/clusterware-node/scripts-available.

All such scripts should include /opt/scyld/clusterware-node/functions.sh for common variables and functions, and should use the attributes.ini described previously to determine what actions are necessary. Cluster administrators are invited to enable and disable these scripts in their root file system images as they see fit and to contribute improved or added scripts back to the ClusterWare developers for the continuing improvement of the product.