Constraints

A Constraint enables you to limit where an execution profile can run workloads to worker nodes with a specified label.

Constraints can be applied to an Execution Profile that limit the list of nodes in the Altair SLC Hub cluster that are eligible to run the given workload.

Operating System Constraint

In an Altair SLC Hub cluster containing a mix of Linux and Windows Worker Nodes, an operating system constraint can be defined on an execution profile to ensure that workloads are only run on Windows nodes or only on Linux nodes as appropriate.

The Operating system field of the Constraints section is used to select the operating system required to run a workload. The field contains a list of supported operating systems which can be selected from the drop down.

Node Label Constraint

Worker nodes in the Altair SLC Hub Cluster can be given one or more node labels, normally when Altair SLC Hub is first configured. This label can then be used to specify which worker node can execute a workload.

Worker node labels are listed in the Node Labels field. Selecting a label in this field will constrain the workload to the identified node. If multiple node labels are specified, a worker node must have all the selected labels for the workload to execute.

Node labels can be combined with other constraints in a profile to provide access to different resources on the same worker node. Node labels can also be used to label nodes for different purposes, for example "Production", "Staging", or "Test". Execution profiles can then be created to ensure that only production jobs are run on the nodes that are labelled with the "Production" label.

If using node labels to identify worker nodes in a cluster to limit where workloads can be run, it is important to ensure that all available execution profiles provide suitable constraints in addition to using node labels. It is also important to ensure that there are no execution profiles made available that do not constrain based on the node label.