# JupyterHub & IRkernel misbehaving -- next steps for debugging?

**URL:** <https://discourse.jupyter.org/t/jupyterhub-irkernel-misbehaving-next-steps-for-debugging/12160>\
**Category:** JupyterHub\
**Tags:** jupyterhub, help-wanted\
**Created:** [December 10, 2021, 6:35pm UTC](https://discourse.jupyter.org/t/jupyterhub-irkernel-misbehaving-next-steps-for-debugging/12160 "2021-12-10T18:35:17Z")\
**Posts on this page:** 3\
**Page:** 1

<div class="post-metadata">

**Author:** ![smeylan](https://yyz1.discourse-cdn.com/flex031/user_avatar/discourse.jupyter.org/smeylan/32/5965_2.png) [@smeylan](https://discourse.jupyter.org/u/smeylan)\
**Post date:** [December 10, 2021, 6:35pm UTC](https://discourse.jupyter.org/t/jupyterhub-irkernel-misbehaving-next-steps-for-debugging/12160/1 "2021-12-10T18:35:17Z")

</div>

I am trying to get an R kernel working in Jupyterhub — it was working on an Ubuntu 16.04 install but it stopped when I upgraded to 20.04 and did a fresh install of everything (default proxy and processor setups; no docker complexities; installed through pip). I followed the instructions from IRkernel for installation, including the dependencies in R and to register the kernel with `IRkernel::installspec()`. I see the kernel then from JupyterLab but when I try to execute some test (`test = 3`), I just see an asterisk until it says the server has stopped responding. In the logs I see a bunch of messages like the following (with --debug passed to JupyterHub).

`Nudge: attempt 70 on kernel 2cfaed33-b05f-4b08-a5d9-80bbc260c431`

I can see from `ps aux` that a kernel was indeed launched  
`/usr/lib/R/bin/exec/R -e IRkernel::main() --args /home/stephan/.local/share/jupyter/runtime/kernel- 2cfaed33-b05f-4b08-a5d9-80bbc260c431.json`

Python kernels are fine. R is fine, and can load IRkerrnel. I an even get a perfectly functional R console with `jupyter console --kernel=ir`. If I run the above R script from `ps aux` without `--slave`, I get an error saying `R_zmq_bind errno: 98 strerror: Address already in us`, so I think the kernel is registering. But now I am at a loss to flush out further error messages – also it is unclear to me whether this is an IRkernel problem or a JupyterHub problem, and hence what community I should ask in. Any ideas? I’m afraid it’s rather urgent as I have a lot of R notebooks I need to access in my academic job.

---

<div class="post-metadata">

**Author:** ![krassowski](https://yyz1.discourse-cdn.com/flex031/user_avatar/discourse.jupyter.org/krassowski/32/1685_2.png) [@krassowski](https://discourse.jupyter.org/u/krassowski)\
**Post date:** [December 10, 2021, 7:20pm UTC](https://discourse.jupyter.org/t/jupyterhub-irkernel-misbehaving-next-steps-for-debugging/12160/2 "2021-12-10T19:20:02Z")

</div>

Please try upgrading `jupyter-server` - the issue you describe was fixed yesterday in v1.13.1 (see [timeout on starting kernels of R and Julia · Issue #633 · jupyter-server/jupyter\_server · GitHub](https://github.com/jupyter-server/jupyter_server/issues/633)). Please let us know if it helped 🙂

---

<div class="post-metadata">

**Author:** ![smeylan](https://yyz1.discourse-cdn.com/flex031/user_avatar/discourse.jupyter.org/smeylan/32/5965_2.png) [@smeylan](https://discourse.jupyter.org/u/smeylan)\
**Post date:** [December 10, 2021, 7:48pm UTC](https://discourse.jupyter.org/t/jupyterhub-irkernel-misbehaving-next-steps-for-debugging/12160/3 "2021-12-10T19:48:32Z")

</div>

Oh fantastic, I was convinced I was in an obscure horrible mess and no one would ever respond! This worked immediately.