# Kernels

**URL:** https://discourse.jupyter.org/c/kernels/42.md

[Latest](https://discourse.jupyter.org/latest.md) · [Categories](https://discourse.jupyter.org/categories.md) · [Tags](https://discourse.jupyter.org/tags.md)

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## [About the Kernels category](https://discourse.jupyter.org/t/about-the-kernels-category/6995)

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**Author:** [@choldgraf](https://discourse.jupyter.org/u/choldgraf)\
**Replies:** 0

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Discuss implementing, using, and managing kernels in the Jupyter ecosystem.

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## [fish-kernel: a Jupyter kernel for the fish shell](https://discourse.jupyter.org/t/fish-kernel-a-jupyter-kernel-for-the-fish-shell/38575)

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**Author:** [@eunos-1128](https://discourse.jupyter.org/u/eunos-1128)\
**Replies:** 0\
**Last updated:** [May 17, 2026, 11:45am UTC](https://discourse.jupyter.org/t/fish-kernel-a-jupyter-kernel-for-the-fish-shell/38575 "2026-05-17T11:45:40Z")

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Hi everyone, I published \`fish-kernel\`, a Jupyter kernel for the fish shell. It allows users to run fish commands directly in Jupyter notebooks, which may be useful for shell-based workflows, environment management, an…

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## [Pure JavaScript kernel](https://discourse.jupyter.org/t/pure-javascript-kernel/38353)

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**Author:** [@Migwell](https://discourse.jupyter.org/u/Migwell)\
**Replies:** 2\
**Last updated:** [January 24, 2026, 1:46pm UTC](https://discourse.jupyter.org/t/pure-javascript-kernel/38353 "2026-01-24T13:46:55Z")

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I haven’t wrapped my head about the Jupyter architecture, but it seems feasible to have a pure JavaScript kernel. Has there been any initiative or planning to do this? If not, how come? I’ve found widgetti/ipyreact, but…

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## [Jupyter Kernel Gateway, Running Kernel Listing](https://discourse.jupyter.org/t/jupyter-kernel-gateway-running-kernel-listing/38327)

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**Author:** [@Vaibhav\_Gupta](https://discourse.jupyter.org/u/Vaibhav_Gupta)\
**Replies:** 1\
**Last updated:** [January 22, 2026, 3:47pm UTC](https://discourse.jupyter.org/t/jupyter-kernel-gateway-running-kernel-listing/38327 "2026-01-22T15:47:46Z")

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FROM python:3.11-slim # Install kernel gateway and a Python kernel RUN pip install --no-cache-dir jupyter-kernel-gateway ipykernel # Create a non-root user (optional but recommended) RUN useradd -m jupyter USER jupyter…

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## [How to async from sync?](https://discourse.jupyter.org/t/how-to-async-from-sync/38261)

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**Author:** [@Maksym\_Sofer](https://discourse.jupyter.org/u/Maksym_Sofer)\
**Replies:** 0\
**Last updated:** [December 30, 2025, 6:35pm UTC](https://discourse.jupyter.org/t/how-to-async-from-sync/38261 "2025-12-30T18:35:47Z")

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Registered to share the story: I manage some data tools for the team, and some of the tools have UI widgets for ease of use (ipywidgets). The problem - ipywidgets that i use synchronous, but i need to call async code…

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## [Design advice for a %%docker magic to run commands in containers](https://discourse.jupyter.org/t/design-advice-for-a-docker-magic-to-run-commands-in-containers/38152)

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**Author:** [@Lunfer](https://discourse.jupyter.org/u/Lunfer)\
**Replies:** 3\
**Last updated:** [December 16, 2025, 12:33pm UTC](https://discourse.jupyter.org/t/design-advice-for-a-docker-magic-to-run-commands-in-containers/38152 "2025-12-16T12:33:49Z")

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Hi all, I’m exploring a design for my project Dockyter, an IPython/Jupyter extension that adds a %%docker magic to run shell commands inside Docker containers while keeping the base Python environment light. The intend…

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## [Running Julia in Jupyter from within a Docker container does not allow precompilation of packages](https://discourse.jupyter.org/t/running-julia-in-jupyter-from-within-a-docker-container-does-not-allow-precompilation-of-packages/18048)

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**Author:** [@Paul\_Hiemstra](https://discourse.jupyter.org/u/Paul_Hiemstra)\
**Replies:** 1\
**Last updated:** [October 28, 2025, 12:04pm UTC](https://discourse.jupyter.org/t/running-julia-in-jupyter-from-within-a-docker-container-does-not-allow-precompilation-of-packages/18048 "2025-10-28T12:04:03Z")

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I’ve been experimenting with Julia, and I run it from within a Docker container. This works great most of the time, but one small issue has been bugging me. Each time I launch or restart the kernel packages are precompil…

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## [Ocaml kernel for Jupyterlite](https://discourse.jupyter.org/t/ocaml-kernel-for-jupyterlite/38026)

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**Author:** [@Davy](https://discourse.jupyter.org/u/Davy)\
**Replies:** 0\
**Last updated:** [October 14, 2025, 6:50pm UTC](https://discourse.jupyter.org/t/ocaml-kernel-for-jupyterlite/38026 "2025-10-14T18:50:31Z")

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Hello everyone ! I’m happy to announce xeus-ocaml, a new kernel to run Ocaml from Jupyterlite notebooks :partying\_face: I’m far from a professional developer, and very new to Ocaml, so do not hesitate to try it with yo…

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## [Notebook Kernell in VSC endlessly loading](https://discourse.jupyter.org/t/notebook-kernell-in-vsc-endlessly-loading/25049)

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**Author:** [@klaveflo](https://discourse.jupyter.org/u/klaveflo)\
**Replies:** 1\
**Last updated:** [October 13, 2025, 4:58pm UTC](https://discourse.jupyter.org/t/notebook-kernell-in-vsc-endlessly-loading/25049 "2025-10-13T16:58:17Z")

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Hi everyone I am a student and we use Visual Studio Code and mainly python to code. Recently we also started using the jupyter notebook extension for VSC and we use a venv (Python 3.12.2) from our teachers as the main k…

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## [Sshpyk — Run Jupyter kernels over SSH as if they were local](https://discourse.jupyter.org/t/sshpyk-run-jupyter-kernels-over-ssh-as-if-they-were-local/38013)

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**Author:** [@caenrigen](https://discourse.jupyter.org/u/caenrigen)\
**Replies:** 0\
**Last updated:** [October 11, 2025, 2:43pm UTC](https://discourse.jupyter.org/t/sshpyk-run-jupyter-kernels-over-ssh-as-if-they-were-local/38013 "2025-10-11T14:43:20Z")

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Hi all! This summer I published sshpyk, a lightweight Python package that lets you launch Jupyter kernels on a remote machine via SSH and use them from many Jupyter front-end (Lab/Notebook/Console) as if they were local…

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## [Single-user setups for local client & remote kernel](https://discourse.jupyter.org/t/single-user-setups-for-local-client-remote-kernel/13882)

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**Author:** [@creepingphlox](https://discourse.jupyter.org/u/creepingphlox)\
**Replies:** 8\
**Last updated:** [October 10, 2025, 6:06pm UTC](https://discourse.jupyter.org/t/single-user-setups-for-local-client-remote-kernel/13882 "2025-10-10T18:06:54Z")

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Apologies for the link formatting, I am only allowed to put 2 links in my post. My requirements I am interested in a setup where I use Jupyter kernels on a remote/headless system (or in a Docker container, or both)). I …

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## [How to connect a local jupyterlab notebook to a remote kernel?](https://discourse.jupyter.org/t/how-to-connect-a-local-jupyterlab-notebook-to-a-remote-kernel/11781)

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**Author:** [@pll\_llq](https://discourse.jupyter.org/u/pll_llq)\
**Replies:** 14\
**Last updated:** [October 10, 2025, 6:05pm UTC](https://discourse.jupyter.org/t/how-to-connect-a-local-jupyterlab-notebook-to-a-remote-kernel/11781 "2025-10-10T18:05:00Z")

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Hi everyone! I need some advice, please. What would be the most simple way to connect a running jupyter lab to a remote kernel? I’ve briefly looked into the kernel and enterprise gateways and some extensions but the JE…

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## [Kernel does not exist error with GAP kernel on Linux](https://discourse.jupyter.org/t/kernel-does-not-exist-error-with-gap-kernel-on-linux/37496)

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**Author:** [@borgch](https://discourse.jupyter.org/u/borgch)\
**Replies:** 0\
**Last updated:** [August 11, 2025, 4:45pm UTC](https://discourse.jupyter.org/t/kernel-does-not-exist-error-with-gap-kernel-on-linux/37496 "2025-08-11T16:45:24Z")

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The python3 kernel is working well, but gap-4 not: $ jupyter kernelspec list …

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## [Kernel Stops Executing Subsequent Code After input() Call (and thus no output) with Custom WebSocket Client](https://discourse.jupyter.org/t/kernel-stops-executing-subsequent-code-after-input-call-and-thus-no-output-with-custom-websocket-client/37185)

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**Author:** [@Zurab\_Shahbanov](https://discourse.jupyter.org/u/Zurab_Shahbanov)\
**Replies:** 0\
**Last updated:** [July 30, 2025, 3:32pm UTC](https://discourse.jupyter.org/t/kernel-stops-executing-subsequent-code-after-input-call-and-thus-no-output-with-custom-websocket-client/37185 "2025-07-30T15:32:58Z")

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Hi I’m developing a custom web IDE client that connects to Jupyter Kernel Gateway via WebSockets. My client correctly sends execute\_request, handles input\_request, and sends input\_reply. The Problem: When my client se…

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## [Running voici with jupyterlite-pyodide-kernel offline/locally?](https://discourse.jupyter.org/t/running-voici-with-jupyterlite-pyodide-kernel-offline-locally/36959)

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**Author:** [@Bigpimpin](https://discourse.jupyter.org/u/Bigpimpin)\
**Replies:** 0\
**Last updated:** [July 22, 2025, 4:25am UTC](https://discourse.jupyter.org/t/running-voici-with-jupyterlite-pyodide-kernel-offline-locally/36959 "2025-07-22T04:25:24Z")

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What is the correct method of using Voici with the jupyterlite-pyodide-kernel so that all packages are not fetched from the cdn/pypi? I’m looking to have it self-contained. I see online you are supposed to use “–pyodid…

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## [Have integrated EG with Yarn , launching a kernel (spark-scala in yarn cluster mode) gets stuck in ACCEPTED state](https://discourse.jupyter.org/t/have-integrated-eg-with-yarn-launching-a-kernel-spark-scala-in-yarn-cluster-mode-gets-stuck-in-accepted-state/35710)

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**Author:** [@vinodraj](https://discourse.jupyter.org/u/vinodraj)\
**Replies:** 0\
**Last updated:** [May 30, 2025, 7:33am UTC](https://discourse.jupyter.org/t/have-integrated-eg-with-yarn-launching-a-kernel-spark-scala-in-yarn-cluster-mode-gets-stuck-in-accepted-state/35710 "2025-05-30T07:33:34Z")

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we have Jupyterhub installed in server A and JEG installed on server B. JEG is configured to launch the kernel jobs on cdp YARN cluster. we were successful to launch the kernel spark-scala in client mode but when we lau…

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## [How can I prevent the jupyter kernel from buffering stdout/stderr?](https://discourse.jupyter.org/t/how-can-i-prevent-the-jupyter-kernel-from-buffering-stdout-stderr/20839)

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**Author:** [@vedantroy](https://discourse.jupyter.org/u/vedantroy)\
**Replies:** 1\
**Last updated:** [May 28, 2025, 9:58am UTC](https://discourse.jupyter.org/t/how-can-i-prevent-the-jupyter-kernel-from-buffering-stdout-stderr/20839 "2025-05-28T09:58:11Z")

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I am using an AsyncKernelManager + AsyncKernelClient to execute code in the jupyter kernel. I notice that even if code executes instantly, stdout/stderr messages both take much longer to appear on the iopub channel than …

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## [Jupyter Enterprise Gateway project status & alternatives](https://discourse.jupyter.org/t/jupyter-enterprise-gateway-project-status-alternatives/34252)

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**Author:** [@Olivier](https://discourse.jupyter.org/u/Olivier)\
**Replies:** 1\
**Last updated:** [April 28, 2025, 2:22pm UTC](https://discourse.jupyter.org/t/jupyter-enterprise-gateway-project-status-alternatives/34252 "2025-04-28T14:22:54Z")

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Hello, It looks like Jupyter Enterprise Gateway has no more release for 1 year. Any information on this project status ? Is there any active project which can meets similar requirements on k8s ? Thanks Best Regards

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## [Java program outputs nothing when run using Jupyter](https://discourse.jupyter.org/t/java-program-outputs-nothing-when-run-using-jupyter/21238)

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**Author:** [@svarma](https://discourse.jupyter.org/u/svarma)\
**Replies:** 2\
**Last updated:** [March 18, 2025, 3:29pm UTC](https://discourse.jupyter.org/t/java-program-outputs-nothing-when-run-using-jupyter/21238 "2025-03-18T15:29:36Z")

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I installed the iJava kernel for Jupyter and am able to execute standalone java statements in the notebook and lab, but when I run simple programs, nothing happens - no error, no output! System.out.println(“Hello World!…

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## [How to see kernel version in JupyterLab?](https://discourse.jupyter.org/t/how-to-see-kernel-version-in-jupyterlab/33492)

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**Author:** [@rootsmusic](https://discourse.jupyter.org/u/rootsmusic)\
**Replies:** 5\
**Last updated:** [March 5, 2025, 6:17pm UTC](https://discourse.jupyter.org/t/how-to-see-kernel-version-in-jupyterlab/33492 "2025-03-05T18:17:44Z")

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The JupyterLab demo is on Binder. One kernel shows: Notebook: demo/Lorenz.ipynb Kernel ID: 3c3f1ace-bd63-4445-8e4b-eeb8a83cdfd7 Kernel Host: jupyter-jupyterlab-jupyterlab-demo-2w21pwmz How can I see that kernel’s …

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## [What is the correct way to make a kernel use a different JVM?](https://discourse.jupyter.org/t/what-is-the-correct-way-to-make-a-kernel-use-a-different-jvm/32648)

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**Author:** [@waldhol](https://discourse.jupyter.org/u/waldhol)\
**Replies:** 0\
**Last updated:** [February 10, 2025, 8:26am UTC](https://discourse.jupyter.org/t/what-is-the-correct-way-to-make-a-kernel-use-a-different-jvm/32648 "2025-02-10T08:26:38Z")

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I have installed the sysml-v2 kernel from here: SysML-v2-Release/install/jupyter/README.adoc at f49ea19a807a2aa45ad1afed0ed62afe41aabdf9 · Systems-Modeling/SysML-v2-Release · GitHub The installer automatically installed…

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## [Questions on the jupyter websocket protocol](https://discourse.jupyter.org/t/questions-on-the-jupyter-websocket-protocol/32493)

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**Author:** [@bkh](https://discourse.jupyter.org/u/bkh)\
**Replies:** 0\
**Last updated:** [February 5, 2025, 8:12pm UTC](https://discourse.jupyter.org/t/questions-on-the-jupyter-websocket-protocol/32493 "2025-02-05T20:12:30Z")

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Hi all, I have a question on the websocket kernel wire protocols detailed here: jupyter\_server/docs/source/developers/websocket-protocols.rst at dd7daf9e6b2050227260d64fddb22bb96187b86d · jupyter-server/jupyter\_server ·…

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## [Can anyone help me in fixing the code](https://discourse.jupyter.org/t/can-anyone-help-me-in-fixing-the-code/32008)

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**Author:** [@Medhavi\_Yennawar](https://discourse.jupyter.org/u/Medhavi_Yennawar)\
**Replies:** 1\
**Last updated:** [January 22, 2025, 3:12pm UTC](https://discourse.jupyter.org/t/can-anyone-help-me-in-fixing-the-code/32008 "2025-01-22T15:12:13Z")

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fix the code after model

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## [Support XQuery , is there any kernel?](https://discourse.jupyter.org/t/support-xquery-is-there-any-kernel/32204)

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**Author:** [@eliselavy](https://discourse.jupyter.org/u/eliselavy)\
**Replies:** 0\
**Last updated:** [January 28, 2025, 4:54pm UTC](https://discourse.jupyter.org/t/support-xquery-is-there-any-kernel/32204 "2025-01-28T16:54:16Z")

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Is there a project to enable XQuery in notebook? I see this , but seems to no more maintain: GitHub - suvarchal/IJython: Jython Kernel for Jupyter/IPython

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## [Setting Limits for Memory Usage and Byte Limits in Jupyter Server Kernels via API](https://discourse.jupyter.org/t/setting-limits-for-memory-usage-and-byte-limits-in-jupyter-server-kernels-via-api/32131)

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**Author:** [@mlb0925](https://discourse.jupyter.org/u/mlb0925)\
**Replies:** 0\
**Last updated:** [January 26, 2025, 7:17pm UTC](https://discourse.jupyter.org/t/setting-limits-for-memory-usage-and-byte-limits-in-jupyter-server-kernels-via-api/32131 "2025-01-26T19:17:15Z")

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I am using Jupyter Server to run code and would like to limit the memory usage, input bytes, and output bytes for each kernel via API. Could you suggest a good solution for this? Thank you.

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## [Kernel for Spark + R](https://discourse.jupyter.org/t/kernel-for-spark-r/31528)

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**Author:** [@romangershgorin](https://discourse.jupyter.org/u/romangershgorin)\
**Replies:** 0\
**Last updated:** [January 9, 2025, 8:22am UTC](https://discourse.jupyter.org/t/kernel-for-spark-r/31528 "2025-01-09T08:22:34Z")

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I am trying to create kernel for R with Spark. So far I was able to install IRkernel package and create config without Spark like below, and it works { "display\_name": "R", "language": "R", "argv": \["R", "--…

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## [Codecells not trusted when running commands via the jupyter client](https://discourse.jupyter.org/t/codecells-not-trusted-when-running-commands-via-the-jupyter-client/31262)

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**Author:** [@tiredstudent](https://discourse.jupyter.org/u/tiredstudent)\
**Replies:** 1\
**Last updated:** [December 29, 2024, 1:14am UTC](https://discourse.jupyter.org/t/codecells-not-trusted-when-running-commands-via-the-jupyter-client/31262 "2024-12-29T01:14:25Z")

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Hi! I’m trying to run commands from outside jupyter using the kernel messaging protocol, which is called by a frontend UI (the project is a plugin to a markdown editor (Obsidian), and the goal is to send the code fence …

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## [Troubleshooting Kernel Communication Issues in Jupyter Notebook](https://discourse.jupyter.org/t/troubleshooting-kernel-communication-issues-in-jupyter-notebook/30942)

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**Author:** [@segidas](https://discourse.jupyter.org/u/segidas)\
**Replies:** 0\
**Last updated:** [December 16, 2024, 6:31am UTC](https://discourse.jupyter.org/t/troubleshooting-kernel-communication-issues-in-jupyter-notebook/30942 "2024-12-16T06:31:52Z")

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Hello I have been facing intermittent communication issues between the Jupyter Notebook interface & kernels, particularly when working with resource-intensive tasks in Python. Sometimes, the kernel disconnects / hangs…

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## [Missing Kernel connection in Jupyter.lab with Python and Powershell kernel](https://discourse.jupyter.org/t/missing-kernel-connection-in-jupyter-lab-with-python-and-powershell-kernel/30417)

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**Author:** [@JupyterPS](https://discourse.jupyter.org/u/JupyterPS)\
**Replies:** 0\
**Last updated:** [November 25, 2024, 6:39pm UTC](https://discourse.jupyter.org/t/missing-kernel-connection-in-jupyter-lab-with-python-and-powershell-kernel/30417 "2024-11-25T18:39:05Z")

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I’m creating a JUPYTER.LAB with a Python and Powershell kernel. It’s done from a Github repository running Docker via Binder and started via an Internet address, (so I have nothing on my PC). When the docker process has …

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## [Connecting to Kernel from outside Docker image](https://discourse.jupyter.org/t/connecting-to-kernel-from-outside-docker-image/17991)

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**Author:** [@srithon](https://discourse.jupyter.org/u/srithon)\
**Replies:** 4\
**Last updated:** [October 18, 2024, 7:39pm UTC](https://discourse.jupyter.org/t/connecting-to-kernel-from-outside-docker-image/17991 "2024-10-18T19:39:52Z")

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Hello, I’ve been trying to start a Jupyter Kernel inside of a jupyter/datascience-notebook Docker container, and connect to it from outside the container with the emacs-jupyter package. I tried to override and forward t…

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