OneSlurm References on

Service Architecture

Wed, 07 Oct 2026 00:00:00 +0000

Components

Component	Where	Role
OneFlow service `OneSlurm`	OpenNebula Front-end	Creates the roles in order and scales the workers
`controller` role	1 VM	`slurmctld`, Munge, optional OpenLDAP, reconciler
`worker` role	1 or more VMs, child of `controller`	`slurmd`, Munge, self-drain hook
OneGate	OpenNebula Front-end	Shares data between the VMs of the service
Service network	Virtual Network	Connects all the VMs. Chosen when the service is created

The service uses deployment: straight and ready_status_gate: true. OneFlow creates the controller first and the workers only after the controller reports READY=YES.

Configuration Parameters

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Service Network

Name	Mandatory	Description
`Service`	Yes	Virtual Network for the controller and the workers

Service Inputs

All the inputs are optional. You set them when you create the service.

LDAP

Used by the controller. The workers get the LDAP settings from the controller through OneGate. See Identity Management.

OneSlurm CLI

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OpenNebula Commands

Run these on the OpenNebula Front-end.

Command	Purpose
`onemarketapp export 'Service OneSlurm' 'Service OneSlurm' --datastore default`	Import the appliance from the Marketplace
`onetemplate update <TEMPLATE_ID>`	Change a controller or worker VM template
`oneflow-template update <SERVICE_TEMPLATE_ID>`	Change the service template
`oneflow-template instantiate 'Service OneSlurm'`	Create a Cluster
`oneflow list`	List the Clusters
`oneflow show <SERVICE_ID>`	Show the roles and VMs of a Cluster
`oneflow scale <SERVICE_ID> worker <NUMBER>`	Change the number of workers
`oneflow delete <SERVICE_ID>`	Delete a Cluster
`onevm ssh <VM_ID>`	Connect to a VM of the Cluster

Commands Inside the VMs

Command	Where	Purpose
`sinfo`	Controller	Partitions and node states
`scontrol show nodes`	Controller	Details of each node
`squeue`	Controller	Job queue
`srun -N1 hostname`	Controller	Run a test job
`scontrol update NodeName=<node> State=DRAIN Reason=<text>`	Controller	Drain a node before you remove it
`scontrol update NodeName=<node> State=RESUME`	Controller	Put a drained or down node back in service
`scontrol delete NodeName=<node>`	Controller	Delete a dynamic node
`journalctl -u oneslurm-reconcile`	Controller	Log of the reconciler
`onegate service show`	Any VM	The service, as OneGate sees it
`getent passwd <user>`	Any VM	Check an LDAP user
`findmnt /home`	Any VM	Check the NFS mount
`cat /etc/one-appliance/status`	Any VM	Result of the appliance configuration

OneSlurm API

Wed, 07 Oct 2026 00:00:00 +0000

OneSlurm has no API of its own. A OneSlurm cluster is a OneFlow service, so you create, scale and delete it with the OneFlow Server API. This page shows the calls relevant to OneSlurm.

Item	Value
Endpoint	`http://<FRONT_END_IP>:2474`
Authentication	HTTP Basic, with an OpenNebula user and password
Format	JSON

The examples use these variables.

FLOW=http://localhost:2474
AUTH='oneadmin:<password>'

Find the Service Template

curl -s -u "$AUTH" $FLOW/service_template

The response lists the service templates in DOCUMENT_POOL.DOCUMENT. Take the ID of the one named Service OneSlurm.