Architecture

Components

This diagram represents all Slurm-web components with their respective roles and integration with Slurm workload manager:

Slurm-web architecture with components roles [ SVG]

Slurm-web is based on 3 components:

agent: Sends requests to Slurm slurmrestd service which exposes a REST API for slurmctld and slurmdbd daemons. The agent is also in charge of the authorizations enforcement and acts as a caching layer over Slurm.
gateway: Performs user authentication and acts as a reserve proxy for the agents.
frontend: The representation layer for the user interface. It is actually served by the gateway application and executed on client side in web browsers.

Integration

In addition to Slurm workload manager, Slurm-web interacts with some other external services and data sources:

Slurm-web integration with external components [ SVG]

The gateway component authenticates users with an entreprise LDAP directory. Slurm-web supports all major LDAP services implementation such as OpenLDAP, FreeIPA and Active Directory with legacy NIS and RFC 2307 bis schemas.

The agent component reads the RBAC autorization policy from a plain INI file with permissions associated to roles and LDAP groups. The component also extracts cluster racking topology from RacksDB database to generate graphical representation of nodes status in the racks. Finally, it connects to Redis in-memory key/value database to save cached data from Slurm.

Protocols

Protocols and authentication realms used for communication between Slurm-web and Slurm components are represented in this diagram:

Protocols in communication between Slurm-web components [ SVG]

All communications from the clients web browsers to Slurm-web agent component are performed with HTTP over TCP/IP network protocols. These network communications can be secured with SSL/TLS (aka. HTTPS) over standard port TCP/443 with a production HTTP server. After initial authentication with LDAP directory, users are authenticated between these components with JSON Web Token (JWT).

Communications between agent component and Slurm slurmrestd daemon are performed with HTTP protocol over a Unix socket. For security reasons slurmrestd checks the agent runs with the same UID/GID as itself with its rest_auth/local plugin.

Slurm slurmrestd supports incoming connections on TCP/IP sockets with rest_auth/jwt plugin but this configuration is not yet supported by Slurm-web. This is currently a limitation in Slurm-web that might change in the future (see #313).

Slurm components communicates with specific binary RPC protocol over TCP/IP sockets, secured by either Munge or Slurm internal mechanism.

Multi-clusters Distribution

Slurm-web is designed to support natively multiple HPC clusters with a central dashboard. In this configuration, the components are distributed as represented in this diagram:

Slurm-web distribution on multiple clusters [ SVG]

In this configuration, the agent component must be deployed on all clusters collocated with Slurm slurmrestd daemon. An agent interacts with only one Slurm cluster.

The gateway can be installed on a central server. It distributes the requests to the agents deployed on the clusters.

Slurm REST API versions

Slurm-web 3.2.0 is officially tested and supported with Slurm REST API v0.0.39. This version of Slurm REST API is available in Slurm 23.02, 23.11 and 24.05.

This table represents all Slurm REST API versions supported by the latest Slurm releases:

REST API versions by Slurm releases
Slurm releases	Supported API versions
Slurm releases	Latest	Compatible	Deprecated
22.05	0.0.38	0.0.37	0.0.36
23.02	0.0.39	0.0.38	0.0.37
23.11	0.0.40	0.0.39	0.0.38
24.05	0.0.41	0.0.40	0.0.39

While Slurm-web is officially tested with a specific version of Slurm REST API, there are actually few changes between API versions (see Slurm OpenAPI plugin release notes for details) so there are chances that it works with other versions. This can be tested by setting [slurmrestd]>version the in agent configuration file. Use it at your own risk!