Houdini 17.5 Nodes TOP nodes

HQueue Scheduler TOP node

Schedules work items using HQueue.

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This will schedule work items using HQueue in order to execute them on remote machines such as a farm.

This requires HQueue to be installed and setup on the local machine.

TOP Attributes



When the schedule submits a work item to HQueue, it will add this attribute to the work item in order to track the HQueue job id.


These are global parameters for all work items using this scheduler.


Submit Graph As Job

Called when the scheduler should cook the entire TOP Network as a standalone job. Displays the status URI for the submitted job.

Working Directory

The relative directory where the work will be generating intermediate files and output. The intermediate files will be placed in a subdirectory. Typically $HIP is used. For running jobs on the farm, the working directory would typically be a mounted directory on all client machines, including the machine scheduling the work.

Job Name

The name of the top-level HQueue Job for submitted cooks.

Override Local Shared Root

Enables overriding the location of local shared root directory.

Local Shared Root Paths

Load from HQueue

Queries the HQueue server to retrieve the local shared root paths.


The local shared root path on Windows.


The local shared root path on macOS.


The local shared root path on Linux.

HQueue Server

URL of the HQueue server. Example: http://localhost:5000

Use Universal HFS

Enable to use the Universal HFS.

Universal HFS

A platform-agnostic path to the $HFS directory.

HFS Per Platform

Linux HFS Path

$HFS path for Linux.

macOS HFS Path

$HFS path for macOS.

Windows HFS Path

$HFS path for Windows.

Message Queue

Task Callback Port

Set the TCP Port used by the Message Queue Server for the XMLRPC callback API. The port must be accessible between farm clients.

Relay Port

Set the TCP Port used by the Message Queue Server connection between PDG and the client that is running the Message Queue Command. The port must be reachable on farm clients by the PDG/user machine.

Job Parms

These job specific parameters can be overridden by each node under the HQueue Scheduler tab on the node’s Schedulers parameter interface.

Job Priority

The job’s HQueue priority. Jobs with higher priorities are scheduled and processed before jobs with lower priorities. 0 is the lowest priority.

Assign To

Specify clients to assign to.

Any Client: Assign to any client.

Listed Clients: Assign to specified clients.

Clients from Listed Groups: Assign to specified client groups.


Names of clients to assign jobs to, separated by space.

Select Clients

Select clients from HQueue to populate the Clients list.

Client Groups

Names of client groups to assign jobs to, separated by space.

Select Groups

Select client groups from HQueue to populate the Client Groups list.

Set Number of CPUs per Job

Enable setting the number of CPUs to use per job.

CPUs per Job

The maximum number of CPUs that will be consumed by the job. If the number exceeds a client machine’s number of CPUs, then the client machine will not be assigned to any the job. Note that multithreading of some jobs can be controlled with Houdini Max Threads. If this is not set, and if Houdini Max Threads is also not set, then the job will have the 'single' tag applied, to ensure that only one will run on a given client.

Houdini Max Threads

Set the HOUDINI_MAXTHREADS environment to the given value. By default HOUDINI_MAXTHREADS is set to the value of CPUs per Job, if enabled.

The default of 0 means to use all available processors.

Positive values will limit the number of threads that can be used. A value of 1 will disable multithreading entirely (limiting to only one thread). Positive values will be clamped to the number of CPU cores available.

If the value is negative, the value is added to the maximum number of processors to determine the threading limit. For example, a value of -1 will use all CPU cores except 1.

Task Environment

Additional work item environment variables can be specified here.


Name of the work item environment variable.


Value of the work item environment variable.


Allowed Host

The hostname of the machine that the job should execute on.

Tag List

Additional job tags to pass to HQueue.

Conditions JSON

Additional job conditions to pass to HQueue in JSON format.

See also

TOP nodes