Why does Orchestrator use Mozilla Rhino instead of something more current?

[Michael Cornn]

I'm not a skilled JS developer. Please correct me if I get some details wrong.

I learned the hard way that Orchestrator's "JavaScript" environment uses Mozilla's Rhino engine. In Aria Automation 8, it's version 1.7R4. In VCF Automation 9, it's 1.7.15. 

Both these Rhino versions are over a decade old. 1.7R4 is compliant with ECMAScript 5 (from 2009). 1.7.15 is only compliant with ECMAScript 6 (from 2015). 

Mozilla's current JS engine is SpiderMonkey, compliant with ECMAScript 15 (from 2024). What prevents Broadcom from using that JS engine? Or another modern JS engine like GraalVM, which complies with ECMAScript 16 (from 2025)? 

Is there a technological limitation? Or is it a business decision?

Using a 14-year-old version of JS makes troubleshooting and research quite difficult. My team had resorted to just vibe coding new actions, because Claude Code can generate 14-year-old syntax faster than we can refactor modern JS. 

[Stefan Schnell]

Hello Michael,

yep, VMware Aria Automation and VCF Automation uses the Rhino JavaScript engine.

Yep, Aria Automation til release 8.18.* uses 1.7R4, VCF Automation 9.0 uses 1.7.15 and VCF Automation 9.1 uses 1.8.0.

Yep, 1.7R4 is 7% compatible with ES2015, 1.7.15 is 46% and 1.8.0 is 62% compatible, source.

The VMware Orchestrator bases on Java. Rhino was developed with Java and is deeply integrated into the Java ecosystem. It would likely be very laborius to replace Rhino with SpiderMonkey, because to use SpiderMonkey in a Java application, you would need to use JNI (Java Native Interface) or newer technologies to interact with SpiderMonkey's C++ code. GraalVM might be an alternative.

In 2007 VMware acquired the Swiss company Dunes. Its technology - particularly the Virtual Service Orchestrator product - is the basis for the VMware vRealize Orchestrator. It bases on Java. So the reason of using Rhino grews out of the product's history.

In newer versions of the Orchestrator (starting with version 8.x), VMware has modernized the architecture to allow other languages, such as Node.js, Python, and PowerShell, to be used natively in actions and workflows. With Node.js you can use more modern JavaScript. However, you lose the integration of the objects implemented by VMware, which can significantly simplify programming.

Best regards
Stefan

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More interesting information at https://blog.stschnell.de
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[Michael Cornn]

Thanks for that detailed explanation. So we can chalk it up to technological inertia. 

I read somewhere that Orchestrator runs the other runtime environments (PowerShell, Python, etc.) in  their own containers, spinning up and spinning down a container every time an action starts and stops. Is that correct? 

Would that explain why sessions don't stay open between actions in a workflow? Like, if a PowerCLI action runs "Connect-VIServer", the next PowerCLI action has to run Connect-VIServer again, because the first session closes when the first action completes. 

[Mayank Goyal]

Yea, I know that's a bummer. However, Broadcom is catching up on that in recent Orchestrator version. As of version 9.1, they already on Rhino 1.8.0. Check here https://blog.stschnell.de/detectRhinoEngineVersion.html

However, if you want to improve this posture to next level, you should definitely shift to Build tools for Aria https://vmware.github.io/build-tools-for-vmware-aria/latest/. Once you past the configuration, you will be a completely developer-focused arena for Automation and Orchestrator. In this approach, you do everything via VS Code and cherry on top, you write code in TypeScript with all the bells and whistles. Expect some friction in the beginning though. https://cloudblogger.co.in/2025/08/08/build-tools-for-aria-challenges-first-rewards-later/


Best Regards,

Mayank Goyal

Regional Consulting Professional Services Team

MBCOM Technologies, a Broadcom & VMware Representative

Mobile: [phone]

[e-mail]<mailto:[e-mail]>

OOO: 27th May 2026


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[Michael Cornn]

Thanks. I'll definitely give this a shot. I've been looking for a way to integrate VS Code with Aria Automation. 

I've never written in TypeScript. If I'm proficient in Python 3 and PowerShell, and familiar with JavaScript, would Type Script be very difficult to pick up?