Platform License Scheduler modes

When configuring your installation of Platform License Scheduler, you must choose which of project mode and cluster mode best suits your needs for each license you use. Both project mode and cluster mode can be configured in one installation, however, all different licenses required by a job must belong to the same mode.

cluster mode

Distributes license tokens to clusters, where LSF scheduling takes over.

Cluster mode emphasizes high utilization of license tokens above other considerations such as ownership. License ownership and sharing can still be configured, but within each cluster instead of across multiple clusters. Preemption of jobs (and licenses) also occurs within each cluster instead of across clusters.

License tokens are re-used by LSF when a job finishes, without waiting for confirmation from lmstat that license tokens are available and reported in the next blcollect cycle. This results in higher license utilization for short jobs.

Cluster mode is new in Platform License Scheduler 8.0.

project mode

Distributes license token to projects configured across all clusters.

Project mode emphasizes ownership of license tokens by specific projects which span multiple clusters. When running in project mode, Platform License Scheduler checks demand from license owners across all LSF clusters before allocating license tokens. The process of collecting and evaluating demand for all projects in all clusters slows down each scheduling cycle. License tokens are distributed in the next scheduling cycle, once lmstat confirms license token availability.

Project mode was the only choice available before Platform License Scheduler 8.0.

Difference between cluster mode and project mode

The following figure illustrates license utilization in cluster mode for short jobs with the corresponding lmstat reporting times:

In cluster mode, when one job finishes running, the next job gets its license immediately without having to wait for the next lmstat interval. For example, 4 jobs requiring license 2 are able to run without waiting for lmstat to report token distribution.

The following figure illustrates license utilization in project mode for short jobs with the lmstat reporting times:

In project mode, each job must wait for lmstat to report token distribution before it can get a license and start running. In this example, 3 jobs requiring liense 2 are able to start within the lmstat intervals illustrated.

When to use cluster mode

Cluster mode may suit your needs if:

  • Your primary goal is to maximize license use.

  • Ownership of licenses is a secondary consideration.

  • Many jobs are short relative to the blcollect cycle (60 seconds by default, set by LM_STAT_INTERVAL).

When to use project mode

Project mode may suit your needs if:

  • Your primary goal is to have licenses used by the group owning the licenses.

  • Maximizing license use is a secondary consideration.

  • Most jobs are long relative to the blcollect cycle (60 seconds by default, set by LM_STAT_INTERVAL).