Kepler Virtual Device Failed to Launch

Vega Open Beta Bug Reports
1

:warning: Before you continue

Before submitting a bug report, please review our troubleshooting documentation at Troubleshoot Issues | Vega Troubleshooting

If you still want to file a bug report, please make sure to fill in all the details below and provide the necessary information.

NOTE: PLEASE ONLY REPORT A SINGLE BUG USING THIS TEMPLATE.
If you’re experiencing multiple issues, please file a separate report for each.

:backhand_index_pointing_right: Bug Description

1. Summary

I was not able to launch the Kepler Virtual Device (KVD), even with a longer than default timeout.

App Name: N/A
App Link on Amazon Appstore (found through Developer Console → Actions column in App List → View on Amazon.com): N/A

Bug Severity
Select one that applies

  • Blocks current development

2. Steps to Reproduce

  1. Follow this guide to install the latest Vega SDK: Install the Vega SDK | Vega Get Started
  2. Execute kepler device simulator start in the terminal

3. Observed Behavior

Explain what actually happened, noting any discrepancies or malfunctions.

The launch process fails with the following message in the end:

"
Launching default instance.
Waiting for virtual device to boot.
Virtual device unresponsive.
Cleaning up. Killing virtual device process with pid 2895214.
Kepler operation FAILED due to an irrecoverable error: The virtual device failed to start within the expected time.
"

4. Expected Behavior

Describe what you expected the SDK to do under normal operation.

I am able to launch the KVD successfully.

4.a Possible Root Cause & Temporary Workaround

Fill out anything you have tried. If you don’t know, N/A is acceptable

1. I tried with a longer timeout "kepler device simulator start --timeout 800", but the result was the same.
2. I tried deleting the entire $HOME/kepler (the default installation location) and reinstalling the latest SDK, but the result was the same.

5. Logs or crash report

(Please make sure to provide relevant logs as attachment)

The first two files were renamed so they could be uploaded.

virtual_device.out.log (514 Bytes)

virtual_device.err.log (1.5 KB)

kepler-2025-12-12.log (1.4 KB) (from $HOME/.kepler/logs)

For crash issues, please refer this guide for faster troubleshooting: Detect Where the App Crash Originates | Design and Develop Vega Apps

  • App/Device Logs

  • Crash Logs

  • Crash Report

  • For issues with Kepler Studio Extension, please share log files from below folders:

     ~/.vscode/extensions/amazon.kepler-extension-<version>/ExtensionLogs
 ~/.vscode/extensions/amazon.kepler-ui-extension-<version>/ExtensionLogs

6. Environment

Please fill out the fields related to your bug below:

  • SDK Version: Output of kepler --version 0.21.5245

  • App State: [Foreground/Background]N/A

  • OS Information
    Please ssh into the device via kepler exec vda shelland copy the output from cat /etc/os-releaseinto the answer section below. Note, if you don’t have a simulator running or device attached kepler exec vda shell will respond with vda: no devices/emulators found

    N/A since the KVD failed to launch.

7. Example Code Snippet / Screenshots / Screengrabs

Include any relevant code or component setup in React Native that can help reproduce the bug.

N/A because the KVD failed to launch.

:backhand_index_pointing_right: Playback Issues

N/A

:backhand_index_pointing_right: Additional Context

Any Additional Context you would like to provide?
Add any other relevant information, such as recent updates to the SDK, dependencies, or device OS that may affect the bug.

The host OS is Ubuntu 24.04. 
No VM was involved in this process.
I previously installed older versions of Kepler SDK (such as v0.18), but did not run into a similar issue with the simulators. To ensure there was no interference from older versions, I removed them ($HOME/.kepler) first before trying out v0.21.
3

Hi @nj5,

Welcome to the Amazon Developer Community!

Thank you for the detailed bug report on the Kepler Virtual Device launch issue. We appreciate you providing comprehensive information including the logs, environment details, and troubleshooting steps you’ve already attempted.

Our team is investigating this issue and will provide an update as soon as we have more information.

Thanks for helping us improve the Vega platform.

Warm regards,
Aishwarya

4

Hi @nj5

Thank you for providing the detailed logs. We’ve completed a thorough analysis of your Kepler Virtual Device launch failure and we’ve identified the possible root cause and steps to resolve it.

Issue Analysis

After examining your logs and trying to reproduce the scenario on a clean Ubuntu 24.04 environment, your issue appears to be related to graphics driver compatibility on your specific Ubuntu 24.04 setup.

Key findings from your logs:

  • MESA graphics rendering errors (dri3_alloc_render_buffer failed, X error: 11)
  • Vulkan library loading failures
  • Configuration file processing issues

Possible Root Cause

Graphics subsystem incompatibility between your Ubuntu 24.04 graphics drivers and the Vega SDK’s rendering requirements.
The fact that the Vega SDK v0.18 worked but v0.21.5245 doesn’t suggests this is a graphics API compatibility regression, which the following driver updates should fix. We just need to align your system configuration with the graphics requirements.

Recommended Resolution Steps

Please try these steps in order:

1. Update Graphics Drivers
sudo apt update
sudo apt install mesa-vulkan-drivers vulkan-tools
sudo apt install --reinstall libgl1-mesa-dri

2. Set Graphics Environment Variables

For Intel integrated graphics:

export MESA_LOADER_DRIVER_OVERRIDE=i965

For AMD graphics:

export MESA_LOADER_DRIVER_OVERRIDE=radeonsi

3. Clean KVD Instance Data
rm -rf ~/kepler/sdk/0.21.5245/kvd/instances/*

4. Retry Launch
kepler device simulator start

Alternative Workaround

If the above steps don’t resolve the issue, you can temporarily use software rendering:
export LIBGL_ALWAYS_SOFTWARE=1
kepler device simulator start

Next Steps

Please try these solutions and let us know the results. If you continue to experience issues, please share:

  1. Your graphics card information: lspci | grep VGA
  2. Current graphics driver version: glxinfo | grep “OpenGL renderer”
  3. Any new error messages
5

Hi yocoyah

Thank you for providing the analysis and the steps to follow.

After (re)installing the packages referenced in step 1, I tried a few different variables to find out which allows the KVD to launch.

First, lspci | grep VGA prints:

00:02.0 VGA compatible controller: Intel Corporation CoffeeLake-H GT2 [UHD Graphics 630]

Then I want to share outputs from a few commands:

  1. MESA_LOADER_DRIVER_OVERRIDE=i965 glxinfo | grep ‘OpenGL renderer string’ prints:

kmsro: driver missing
glx: failed to create dri3 screen
failed to load driver: i965
OpenGL renderer string: llvmpipe (LLVM 20.1.2, 256 bits)

  1. MESA_LOADER_DRIVER_OVERRIDE=iris glxinfo | grep ‘OpenGL renderer string’ prints:

OpenGL renderer string: Mesa Intel(R) UHD Graphics 630 (CFL GT2)

(Note that I don’t have much knowledge in this domain, but I assume iris is the default value.)

  1. LIBGL_ALWAYS_SOFTWARE=1 glxinfo | grep ‘OpenGL renderer string’ prints:

OpenGL renderer string: llvmpipe (LLVM 20.1.2, 256 bits)

  1. glxinfo | grep ‘OpenGL renderer string’ prints:

OpenGL renderer string: Mesa Intel(R) UHD Graphics 630 (CFL GT2)

The observation is that with MESA_LOADER_DRIVER_OVERRIDE=i965 or LIBGL_ALWAYS_SOFTWARE=1, I was able to launch an KVD instance. That’s likely because even the former, due to some issues, switched to software rendering, as shown in the outputs above. I could rely on software rendering as a temporary workaround, but it would be better if that’s not necessary.

I’m not sure if it makes any difference, but it seems that i965 hasn’t been included by default since Ubuntu 22.04.

I want to provide additional contexts which might useful:

  1. The laptop I’m using has two GPUs: Intel(R) UHD Graphics 630 (GPU0), and Nvidia Quadro P1000 (GPU1) using the driver version 580.95.5.0
  2. When I tried out Kepler 0.18 earlier, I believe the OS was still Ubuntu 22.04 at the time. I upgraded to 24.04 recently.

I’m happy to provide other information if needed, but there’s likely going to be delays of responses because of the December plans.

6

Hello @nj5 , apologies for the delayed response.

Thank you for the detailed investigation - this provides excellent insight into the issue. You’ve correctly identified that your Intel CoffeeLake-H GT2 requires the iris driver (not i965), and the fact that KVD works with software rendering confirms the SDK itself is functioning properly.

Before drawing conclusions, the next step is to validate if the issue still reproduces with the latest Vega SDK.

Validate with Latest Vega SDK

Please try the following:

  1. Download and install the latest Vega SDK (current: 0.22.5600): Install the Vega SDK | Vega Get Started
  2. Launch Vega Virtual Device (VVD) on Ubuntu 24.04 without setting any environment overrides: vega virtual-device start

Root Cause Analysis

If the issue continues with SDK v0.22, one possible contributing factor could be the hybrid GPU setup on the system, which includes Intel UHD Graphics 630 (using the iris driver) and an NVIDIA Quadro P1000 (driver 580.95.5.0). In some environments, this configuration can affect how graphics libraries and backends are selected at runtime.

KVD is likely trying to initialize graphics on the wrong GPU or getting confused by the dual-GPU setup. This explains why it works with software rendering but fails with hardware acceleration.

Next Steps to Try

Option 1: Force Intel GPU Selection

export DRI_PRIME=0
export MESA_LOADER_DRIVER_OVERRIDE=iris
kepler device simulator start --timeout 800

Option 2: Switch to Intel-Only Mode

# Check current GPU mode
prime-select query

# Switch to Intel-only (requires reboot)
sudo prime-select intel
# Reboot system
kepler device simulator start --timeout 800

Option 3: Verify GPU Status

# Check which GPU is active
nvidia-smi
glxinfo | grep "OpenGL vendor"

Expected Outcome
This may resolve the hardware acceleration issue while maintaining full performance. Hybrid GPU setups are a common source of graphics initialization problems in development tools. Please try these steps and let us know the results. If successful, you can switch back to your preferred GPU mode when not using KVD.

7

Hi @Monica , thanks for the response.

I upgraded to Vega SDK 0.22.5600, but unfortunately, the behavior seems to be the same.

I think I will let it be for now, and revisit this issue if the performance impact is noticeable.

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