Jupyter notebook Docker image runs in Docker but not in Kubernetes

Question

I created a Dockerfile for running Jupyter in Docker.

FROM ubuntu:latest
FROM python:3.7

WORKDIR /app
ADD . /app

RUN pip install -r requirements.txt

CMD ["jupyter", "notebook", "--allow-root", "--ip=0.0.0.0"]

My requirements.txt file looks like this:

jupyter
git+https://github.com/kubernetes-client/python.git

I ran docker build -t hello-jupyter . and it builds fine. Then I ran docker run -p 8888:8888 hello-jupyter and it runs fine.

I'm able to open Jupyter notebook in a web browser (127.0.0.1:8888) when I run the Docker image hello-jupyter.

Now I would like to run Jupyter as a Kubernetes deployment. I created this deployment.yaml file:

apiVersion: v1
kind: Service
metadata:
  name: hello-jupyter-service
spec:
  selector:
    app: hello-jupyter
  ports:
  - protocol: "TCP"
    port: 8888
    targetPort: 8888
  type: LoadBalancer


---
apiVersion: apps/v1
kind: Deployment
metadata:
  name: hello-jupyter
spec:
  replicas: 4
  selector:
    matchLabels:
      app: hello-jupyter
  template:
    metadata:
      labels:
        app: hello-jupyter
    spec:
      containers:
      - name: hello-jupyter
        image: hello-jupyter
        imagePullPolicy: Never
        ports:
        - containerPort: 8888

I ran this command in shell:

$ kubectl apply -f deployment.yaml
service/hello-jupyter-service unchanged
deployment.apps/hello-jupyter unchanged

When I check my pods, I see crash loops

$ kubectl get pods
NAME                             READY   STATUS             RESTARTS   AGE
hello-jupyter-66b88b5f6d-gqcff   0/1     CrashLoopBackOff   6          7m16s
hello-jupyter-66b88b5f6d-q59vj   0/1     CrashLoopBackOff   15         55m
hello-jupyter-66b88b5f6d-spvl5   0/1     CrashLoopBackOff   6          7m21s
hello-jupyter-66b88b5f6d-v2ghb   0/1     CrashLoopBackOff   6          7m20s
hello-jupyter-6758977cd8-m6vqz   0/1     CrashLoopBackOff   13         43m

The pods have crash loop as their status and I'm not able to open Jupyter in a web browser.

What is wrong with the deployment.yaml file? The deployment.yaml file simply runs the Docker image hello-jupyter in four different pods. Why does the Docker image run in Docker but not in Kubernetes pods?

Here is the log of one of my pods:

$ kubectl logs hello-jupyter-66b88b5f6d-gqcff
[I 18:05:03.805 NotebookApp] Writing notebook server cookie secret to /root/.local/share/jupyter/runtime/notebook_cookie_secret
Traceback (most recent call last):
  File "/usr/local/lib/python3.7/site-packages/traitlets/traitlets.py", line 537, in get
    value = obj._trait_values[self.name]
KeyError: 'port'

I do specify a port in my deployment.yaml file. I'm not sure why I get this error in the log.

Show us the logs of the pod.

Klaus D.
– Klaus D.

2021-11-05 17:59:41 +00:00
Commented Nov 5, 2021 at 17:59 — Klaus D.
– Klaus D., Commented Nov 5, 2021 at 17:59
@KlausD. I included a log

ktm5124
– ktm5124

2021-11-05 18:11:52 +00:00
Commented Nov 5, 2021 at 18:11 — ktm5124
– ktm5124, Commented Nov 5, 2021 at 18:11
Looks like a bug in your code or missing configuration.

Klaus D.
– Klaus D.

2021-11-05 18:15:09 +00:00
Commented Nov 5, 2021 at 18:15 — Klaus D.
– Klaus D., Commented Nov 5, 2021 at 18:15

Bazhikov · Accepted Answer · 2021-11-09 18:26:34Z

1

There are many reasons on getting the CrashLoopBackOff error. In your case, it seems like your deployment file is locked or a lack of resources prevents the container from loading.

As I understood, you've built docker image locally and added it to your local Docker registry. Since imagePullPolicy: Never specified and there is no error ErrImageNeverPull, so there is no problem with your docker registries between your local docker and kubernetes.

You can start by running the command: kubectl describe pod [name] to get more from kubelet.

Unless, try deploying single pod first instead of deployment with 4 replicas to make sure that kubernetes runs your image correctly.

answered Nov 9, 2021 at 18:26

Bazhikov

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