"No graphics display found" Even though display is present with VNC(KasmVNC)

Run condition:

• Ubuntu 20.04 Focal Forsa (Docker)
• Architecture: AMD64
• GUI Session: KasmWeb Session & KasmVNC
• MATLAB version: R2023b

Hello, currently, I am trying to run MATLAB on docker container.

I currently found Kasm Workspace as an ideal solution since it can provide easy access to container deployment with GUI.

Kasm deploys docker container on designated server and shows GUI session using KasmVNC.

However, I soon found that running MATLAB installer on Kasm workspace shows me the following error:

```

No graphics display found. Unable to start application in GUI mode. Consider relaunching the app in a graphical environment.

```

I checked if openGL is avaiable using mesa-utils and I checked that using openGL worked with no problem using llvmpipe:

I tested this again using standaone KasmVNC container called webtop. And matlab installer worked without showing that message.

Therefore, I concluded that it is not a problem of KasmVNC itself, but a problem of Kasm Workspace image's VNC configuration.

What I would like to ask are:

• How MATLAB detects graphical session? It seems it uses method other than just checking DISPLAY environment variable.
• What would be the expected cause of this problem?

These information will be very helpful for debugging container image.

Thank you in advance.

Answer 1

[Angelo Yeo]

안녕하세요.

설치와 관련된 이슈는 아래의 가이드를 따라 설치지원팀에 문의하시면 가장 효과적으로 지원받으실 수 있습니다.

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1. 웹으로 지원 요청

설치지원팀으로의 문의는 라이센스 번호와 함께, 1) 매스웍스 홈페이지에서 로그인 후, 2) http://www.mathworks.co.kr/support/contact_us/index.html 로 이동 3) 서비스 요청하기 > 4) 기술 지원: "설치,..." > 5) "설치, 라이선스 매니저, 시작 등" > 빨간색 별표 항목을 모두 채워주시고 해당 에러 문의하실 수 있습니다.

2. 전화로 지원 요청

대표번호 02-6006-5100 에서 안내 멘트에 따라 4번 그리고 1번을 선택하여 설치 지원팀으로 연결하실 수 있습니다.

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[Dongho Kim]

Thank you for the contact.