Swarm not working after 3.6 -> VRay Next SP1 update

[jskt]

We have a working VRay Swarm installation with 7 dedicated render nodes and 2 separate non-rendering master nodes.

After updating from VRay 3.6 to VRay Next (standalone install on all nodes, VRay Next for Rhino installed on the workstation), the render slaves go into 'assigned' mode, but never start rendering when they get a job.

License server shows plenty of available render node licenses.

I've uploaded the VRay build to the Swarm, and tried forcing the nodes to use that build (4.20.01 a1698aff [aec] Sep 19 2019 10:01:36), which has not helped.

The logs show the following happening repeatedly on a 30-second interval on the slaves:

[2019/Oct/4|15:59:41] [26 MB] Reading configuration from "C:\Users\kta_rendernode\AppData\Roaming\Chaos Group\vray-swarm\work\vray-swarm\V-Ray\4e370d94-f59f-48c3-9eab-6fe4f3258a27\bin\/vrayconfig.xml"
[2019/Oct/4|15:59:42] [46 MB] ===============================================
[2019/Oct/4|15:59:42] [46 MB] V-Ray Standalone, version Next Standalone, update 2.1 for x64
[2019/Oct/4|15:59:42] [46 MB] Copyright (C) 2000-2019 Chaos Group Ltd. All rights reserved.
[2019/Oct/4|15:59:42] [46 MB] Use -credits option for additional third-party copyright notices.
[2019/Oct/4|15:59:42] [46 MB]
[2019/Oct/4|15:59:42] [46 MB] Build a1698aff from Sep 19 2019, 10:00:44
[2019/Oct/4|15:59:42] [46 MB] Compiled with Microsoft Visual C++ compiler, version 19.12
[2019/Oct/4|15:59:42] [46 MB] Operating system is Microsoft(tm) Windows(tm), version 6.2,
[2019/Oct/4|15:59:42] [46 MB]
[2019/Oct/4|15:59:42] [46 MB] V-Ray core version is 4.20.01
[2019/Oct/4|15:59:42] [46 MB] ===============================================
[2019/Oct/4|15:59:42] [46 MB]
[2019/Oct/4|15:59:42] [50 MB] Loading plugins from "C:\Users\kta_rendernode\AppData\Roaming\Chaos Group\vray-swarm\work\vray-swarm\V-Ray\4e370d94-f59f-48c3-9eab-6fe4f3258a27\bin/plugins/vray_*.dll"
[2019/Oct/4|15:59:42] [87 MB] 90 plugin(s) loaded successfully
[2019/Oct/4|15:59:42] [87 MB] Finished loading plugins.
[2019/Oct/4|15:59:42] [87 MB] Using folder "C:\Users\KTA_RE~1\AppData\Local\Temp\vray_assets_cache" for caching assets for DR.
[2019/Oct/4|15:59:42] [87 MB] Using file "C:\Users\KTA_RE~1\AppData\Local\Temp\vray_assets_cache/cache_info_20208.txt" for storing assets cache information.
[2019/Oct/4|15:59:42] [87 MB] Entering server mode - waiting for render requests on port 20208. Press Ctrl+C to exit.
[2019/Oct/4|15:59:42] V-Ray process started
[2019/Oct/4|16:00:11] Stopping V-Ray...

Any idea what's going on?

[ivan.slavchev]

If you use just SWARM you don't need to install V-Ray Standalone additionally since SWARM will transfer the build, if it's not already present, from the workstation to the render node before rendering.
From the log you've posted, it looks like that SWARM cannot successfully start V-Ray. You can check if there isn't already another process running on the same port. To do that:
1. Disable V-Ray in SWARM from the slider in the upper-right corner - https://docs.chaosgroup.com/display/...SwarmInterface
2. Run

netstat -ano | find "20208"

in CMD.
3. If it lists a process - you can check which process is running on the port

tasklist /FI "PID eq PID_of_the_found_process"

[jskt]

That netstat command returns blank. What's the next step?