[🐛 Bug]: Video Live Streaming of Node Test Executions runs to a blank page on Kubernetes

[kherath17]

What happened?

I have setup Selenium Hub (selenium/hub:latest) and unable to view the live execution happening on the node , runs into a blank page

Command used to start Selenium Grid with Docker

Started through kubernetes , following is my deployment.yaml

apiVersion: apps/v1
kind: Deployment
metadata:
  name: selenium-hub
  labels:
    app: selenium-hub
spec:
  replicas: 1
  selector:
    matchLabels:
      app: selenium-hub
  template:
    metadata:
      labels:
        app: selenium-hub
    spec:
      containers:
      - name: selenium-hub
        #image: selenium/hub:4.13.0-20231004 #4.1,4.13
        image: selenium/hub:latest
        ports:
          - containerPort: 4444
          - containerPort: 4443
          - containerPort: 4442
        resources:
          limits:
            memory: "4000Mi"
            cpu: "2"
          requests:
            memory: "4000Mi"
            cpu: "2"  
        livenessProbe:
          httpGet:
            path: /wd/hub/status
            port: 4444
          initialDelaySeconds: 30
          timeoutSeconds: 5
        readinessProbe:
          httpGet:
            path: /wd/hub/status
            port: 4444
          initialDelaySeconds: 30
          timeoutSeconds: 5

I have also setup the respective SVCs and Ingress Rules

Relevant log output

NA

Operating System

Windows 11

Docker Selenium version (tag)

4.14.1

[github-actions]

@kherath17, thank you for creating this issue. We will troubleshoot it as soon as we can.

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Thank you!

[VietND96]

Hi @kherath17, did you start the grid setup using helm chart selenium-grid? Or have you created your own K8s manifest files for deployment?

[kherath17]

@VietND96 Its my own deployment files I have used

[VietND96]

Oh, so could you please also share the deployment file of the browser node for reference?

[kherath17]

@VietND96 FYI I have used a POD as below

apiVersion: v1
kind: Pod
metadata:
name: selenium-node-chrome
labels:
name: selenium-node-chrome
app: selenium-node-chrome
spec:
volumes:
- name: dshm
emptyDir:
medium: Memory
containers:
- name: selenium-node-chrome
image: selenium/node-chrome:4.13.0-20231004
ports:
- containerPort: 5555
#- containerPort: 7900
volumeMounts:
- mountPath: /dev/shm
name: dshm
env:
- name: SE_EVENT_BUS_HOST
value: "selenium-hub"
- name: SE_EVENT_BUS_SUBSCRIBE_PORT
value: "4443"
- name: SE_EVENT_BUS_PUBLISH_PORT
value: "4442"
- name: SE_NODE_MAX_SESSIONS
value: "2"
resources:
limits:
memory: "1000Mi"
cpu: ".5"

[VietND96]

reproduce.txt
Based on your input, I created a simple file with hub (deploy, svc) and node deploy. Then deployed it via kubectl apply, and started a test execution, I could see the video stream properly.
Can you try the next step checking pod logs of the browser node, is there any error logs related to "start-novnc"?
Moreover, I saw you mentioned above that "ingress rules" is configured. Can you check the ingress handles vnc request properly also?

[kherath17]

@VietND96 appreciate your effort looking into this , since it works on your end I doubt if its the ingress , would you be able to share me the ingress file you have used

[VietND96]

Actually, I didn't apply ingress in above case, only 3 components as .txt that I shared. I access the grid view inside cluster via ClusterIP only. So if your end is using ingress and facing that issue, can you share your ingress, so I can take a look?

[kherath17]

@VietND96 here is my ingress

apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
name: qlabv2-ingress
namespace: qlabv2
annotations:
nginx.ingress.kubernetes.io/rewrite-target: /$2
spec:
ingressClassName: nginx
rules:

• http:
  paths:
  • backend:
    service:
    name: selenium-hub-service
    port:
    number: 80
    path: /qlabv2(/|$)(.*)
    pathType: ImplementationSpecific

[kherath17]

HI @VietND96 do you see any misconfigurations in my ingress?

[VietND96]

Hi @kherath17 , it looks like ingress using path prefix and rewrite-target with regexp caused the issue. Some URL after redirected is incorrect. e.g
When goto http://hostname/qlabv2, it should redirect to http://hostname/qlabv2/ui, but actually it was http://hostname/ui
Similarly, when opening video stream page, vnc request should call ws://hostname/qlabv2/session/79c652bc117b51a5fefda5b4be0c4854/se/vnc but it was ws://hostname/session/79c652bc117b51a5fefda5b4be0c4854/se/vnc - 404 not found, and no video stream on page

Currently, I only can suggest you use path: / - it works on my end.
For the case path prefix with rewrite-target using regexp. I'll let you know if I am able to find a configuration-snippet can handle it.

[kherath17]

Thank You @VietND96 for clarifying the root cause , but unfortunately I'm unable to use path: / since there's an already running ingress for that path , hence I will need to use some other path to route it

[diemol]

Thank you for troubleshooting, @VietND96! Are you in the Selenium Slack workspace?

[VietND96]

Hi @diemol , I was just aware and joined the Selenium Slack workspace.

[VietND96]

Hi @kherath17 , I suggest a workaround for prefix path config
Below sample with selenium grid runs on http://hostname/qlabv2
By using SE_SUB_PATH. In the hub deploy, add ENV for hub container

          env:
            - name: SE_SUB_PATH
              value: /qlabv2

Now, without ingress, grid view can be accessed via http://ClusterIP:4444/qlabv2/
The ingress configs would be

apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: selenium-ingress
  namespace: default
  annotations:
    kubernetes.io/ingress.class: nginx
    nginx.ingress.kubernetes.io/app-root: /qlabv2
    nginx.ingress.kubernetes.io/rewrite-target: /$2
    nginx.ingress.kubernetes.io/use-regex: "true"
spec:
  rules:
    - http:
        paths:
          - path: /qlabv2(/|$)(.*)
            pathType: Prefix
            backend:
              service:
                name: selenium-hub
                port:
                  number: 4444
          - path: /(/?)(session/.*/se/vnc)
            pathType: Prefix
            backend:
              service:
                name: selenium-hub
                port:
                  number: 4444

With this config it will resolve redirect issue we mentioned above

• http://hostname/qlabv2 -> http://hostname/qlabv2/ui - 200 OK
• ws://hostname/session/79c652bc117b51a5fefda5b4be0c4854/se/vnc -> ws://hostname/qlabv2/session/79c652bc117b51a5fefda5b4be0c4854/se/vnc - 101 Switching Protocols

Deployment file for your reference - workaround.txt

---

Hi @diemol , I also have a doubt here, even we set SE_SUB_PATH but url of session vnc does not contain the sub path.
I also try to set in node this ENV

        - name: SE_NODE_GRID_URL
          value: "http://selenium-hub:4444/qlabv2"

but in node Capabilities, the URL still not have sub path

  "se:vnc": "ws://selenium-hub:4444/session/623cb93cd9438c195578b7edc5b0b534/se/vnc",
  "se:vncEnabled": true,

I saw the same issue discussed in SeleniumHQ/selenium#9980, and there was a commit fixed SeleniumHQ/selenium@ca9b451 by you. Do you know this? @diemol

[kherath17]

Hi @VietND96 the workaround has successfully resolved my issue, thank you and appreciate your effort and time. :)

[github-actions]

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