Licenses Guide
Licenses Overview
Slurm can help with software license management by assigning available licenses to jobs at scheduling time. If the licenses are not available, jobs are kept pending until licenses become available. Licenses in Slurm are essentially shared resources, meaning configured resources that are not tied to a specific host but are associated with the entire cluster.
Licenses in Slurm can be configured in two ways:
- Local Licenses: Local licenses are local to the cluster using the slurm.conf in which they are configured.
- Remote Licenses: Remote licenses are served by the database and are configured using the sacctmgr command. Remote licenses are dynamic in nature as upon running the sacctmgr command, the slurmdbd updates all clusters the licenses are assigned to.
Local Licenses
Local licenses are defined in the slurm.conf using the Licenses option.
slurm.conf:
Licenses=fluent:30,ansys:100
Configured licenses can be viewed using the scontrol command.
$ scontrol show lic
LicenseName=ansys
Total=100 Used=0 Free=100 Remote=no
LicenseName=fluent
Total=30 Used=0 Free=30 Remote=no
Requesting licenses is done by using the -L, or --licenses, submission option.
$ sbatch -L ansys:2 script.sh
Submitted batch job 5212
$ scontrol show lic
LicenseName=ansys
Total=100 Used=2 Free=98 Remote=no
LicenseName=fluent
Total=30 Used=0 Free=30 Remote=no
Remote Licenses
Use Case
A site has two license servers, one serves 100 Nastran licenses provided by FlexNet and the other serves 50 Matlab licenses from Reprise License Management. The site has two clusters named "fluid" and "pdf" dedicated to run simulation jobs using both products. The managers want to split the number of Nastran licenses equally between clusters, but assign 70% of the Matlab licenses to cluster "pdf" and the remaining 30% to cluster "fluid".
Configuring Slurm for the use case
Here we assume that both clusters have been configured correctly in the slurmdbd using the sacctmgr command.
$ sacctmgr show clusters format=cluster,controlhost
Cluster ControlHost
---------- ---------------
fluid 143.11.1.3
pdf 144.12.3.2
The licenses are added using the sacctmgr command, specifying the total count of licenses and the percentage that should be allocated to each cluster. This can be done either in one step or through a multi-step process.
One step:
$ sacctmgr add resource name=nastran cluster=fluid,pdf \ count=100 percentallowed=50 server=flex_host servertype=flexlm type=license Adding Resource(s) nastran@flex_host Cluster - pdf 50% Cluster - fluid 50% Settings Name = nastran Server = flex_host Description = nastran ServerType = flexlm Count = 100 Type = License
Multi-step:
$ sacctmgr add resource name=matlab count=50 server=rlm_host \ servertype=rlm type=license Adding Resource(s) matlab@rlm_host Settings Name = matlab Server = rlm_host Description = matlab ServerType = rlm Count = 50 Type = License $ sacctmgr add resource name=matlab server=rlm_host cluster=pdf percentallowed=70 Adding Resource(s) matlab@rlm_host Cluster - pdf 70% Settings Server = rlm_host Type = License $ sacctmgr add resource name=matlab server=rlm_host cluster=fluid percentallowed=30 Adding Resource(s) matlab@rlm_host Cluster - fluid 30% Settings Server = rlm_host Type = License
The sacctmgr command will now display the grand total of licenses.
$ sacctmgr show resource
Name Server Type Count % Allocated ServerType
---------- ---------- -------- ------ ----------- ----------
nastran flex_host License 100 100 flexlm
matlab rlm_host License 50 100 rlm
$sacctmgr show resource withclusters
Name Server Type Count % Allocated ServerType Cluster % Allowed
---------- ---------- -------- ------ ----------- ---------- ---------- ----------
nastran flex_host License 100 100 flexlm pdf 50
nastran flex_host License 100 100 flexlm fluid 50
matlab rlm_host License 50 100 rlm pdf 70
matlab rlm_host License 50 100 rlm fluid 30
The configured licenses are now visible on both clusters using the scontrol command.
$ scontrol show lic
LicenseName=matlab@rlm_host
Total=35 Used=0 Free=35 Remote=yes
LicenseName=nastran@flex_host
Total=50 Used=0 Free=50 Remote=yes
# On cluster "fluid":
$ scontrol show lic
LicenseName=matlab@rlm_host
Total=15 Used=0 Free=15 Remote=yes
LicenseName=nastran@flex_host
Total=50 Used=0 Free=50 Remote=yes
When submitting jobs to remote licenses, the name and server must be used.
$ sbatch -L nastran@flex_host script.sh Submitted batch job 5172
License percentages and counts can be modified as shown below:
$ sacctmgr modify resource name=matlab server=rlm_host set \
count=200
Modified server resource ...
matlab@rlm_host
Cluster - pdf - matlab@rlm_host
Cluster - fluid - matlab@rlm_host
$ sacctmgr modify resource name=matlab server=rlm_host \
cluster=pdf set percentallowed=60
Modified server resource ...
Cluster - pdf - matlab@rlm_host
$ sacctmgr show resource withclusters
Name Server Type Count % Allocated ServerType Cluster % Allowed
---------- ---------- -------- ------ ----------- ---------- ---------- ----------
nastran flex_host License 100 100 flexlm pdf 50
nastran flex_host License 100 100 flexlm fluid 50
matlab rlm_host License 200 90 rlm pdf 60
matlab rlm_host License 200 90 rlm fluid 30
Licenses can be deleted either on the cluster or all together as shown:
$ sacctmgr delete resource where name=matlab server=rlm_host \
cluster=fluid
Deleting resource(s)...
Cluster - fluid - matlab@rlm_host
$ sacctmgr delete resource where name=nastran server=flex_host
Deleting resource(s)...
nastran@flex_host
Cluster - pdf - nastran@flex_host
Cluster - fluid - nastran@flex_host
$ sacctmgr show resource withclusters
Name Server Type Count % Allocated ServerType Cluster % Allowed
---------- ---------- -------- ------ ----------- ---------- ---------- ----------
matlab rlm_host License 200 60 rlm pdf 60
Dynamic licenses
When the license counter and percentage is updated using the sacctmgr command, the values are updated in the database and the updated values are sent to the slurmctld daemon. It is possible for sites to write a script that detects global license counter changes due to new licenses being added, or old licenses being removed, and updates Slurm. Should the license count decrease, the running jobs will not be affected, only the dispatch of new jobs will reflect the new license count.
Last modified 25 June 2019