Platform LSF Administration Guide Version 6.2

Chapter 8
Platform LSF Licensing
Administering Platform LSF
191
Floating Client Licenses
LSF floating client is valuable if you have a cluster in which not all of the hosts will be
active at the same time. In this section, you will learn how to save money through
distributing your licenses efficiently.
An LSF floating client license is a type of LSF license to be shared among several client
hosts at different times. Floating client licenses are not tied to specific hosts. They are
assigned dynamically to any host that submits a request to LSF. The number of licenses
acts as a license pool for the cluster from which LSF clients can draw required licenses.
Although floating client licenses are supported, LSF does not support floating server
licenses.
Client hosts and floating client hosts
Read this to differentiate between a regular client host and a floating client host.
In LSF, you can have both client hosts and floating client hosts. The difference is in the
type of license purchased.
If you purchased a regular (fixed) client license, LSF client hosts are static. The client
hosts must be listed in
lsf.cluster.cluster_name. The license is fixed to the hosts
specified in
lsf.cluster.cluster_name and whenever client hosts change, you must
update it with the new host list.
If you purchased a floating client license, LSF floating client hosts are dynamic. They are
not listed in
lsf.cluster.cluster_name. Since LSF does not take into account the
host name but the number of floating licenses, clients can change dynamically and
licenses will be distributed to clients that request to use LSF. When you submit a job
from any unlicensed host, and if there are any floating licenses free, the host will check
out a license and submit your job to LSF. However, once a host checks out a floating
client license, it keeps that license for the rest of the day, until midnight. A host that
becomes a floating client behaves like a fixed client all day, then at 12 midnight it releases
the license. At that time, the host turns back into a normal, unlicensed host, and the
floating client license becomes available to any other host that needs it.
How floating licenses work in LSF
Read this to understand how floating licenses work. You will want to read this before
configuring your cluster to use this distribution technique.
When the master LIM starts up, it verifies how many floating licenses there are for the
cluster as specified in
lsf.cluster.cluster_name with the parameter
FLOAT_CLIENTS. The master LIM checks out the licenses and keeps track of license
information—how many floating licenses have been assigned, and which client hosts are
using the licenses.
Floating client licenses expire at midnight (local time) on the day the license was issued.
The master LIM checks the host list and removes any floating client hosts whose license
has expired.
License reset
Whenever the master LIM is restarted, all LSF floating client licenses are released and
checked out again.