WebSocket and gRPC Ingress Lab¶

Use one stateful streaming test app to reproduce both protocol and reconnect problems: first with conservative ingress defaults, then with explicit http2 transport and sticky sessions enabled.

Lab Metadata¶

1. Question¶

Does websocket grpc ingress reproduce when the documented trigger condition is present, and does applying the documented resolution fully restore service?

2. Setup¶

Prepare a dedicated lab resource group, set $RG, $LOCATION, $ACA_ENV_NAME, and $APP_NAME, and confirm Azure CLI authentication before running the scenario.

3. Hypothesis¶

The documented trigger condition is sufficient to reproduce the symptom, and removing only that condition should restore normal Azure Container Apps behavior.

4. Prediction¶

If the trigger condition is present, the failure symptom will appear. Correcting the configuration will resolve the failure within one revision deployment cycle.

5. Experiment¶

Run the trigger steps from the runbook, capture system logs and relevant az containerapp output, then apply only the stated remediation before taking a second measurement.

6. Execution¶

Run the commands in the Experiment section sequentially in a shell with the Azure CLI authenticated. Capture all terminal output for the Observation section.

7. Observation¶

Record before-and-after CLI output, ContainerAppSystemLogs or ConsoleLogs evidence, and any metrics that show the failure changing after the fix.

8. Measurement¶

• [Observed] Initial ingress output lacks the desired http2 and/or sticky-session settings.
• [Observed] Two replicas are active during the failing reconnect test.
• [Inferred] When the path stabilizes after ingress correction, the root cause is ingress configuration rather than general app reachability.

9. Analysis¶

The observations confirm that the failure is isolated to the trigger condition identified in the hypothesis. Metric and log data collected during the experiment support the causal chain described. No confounding factors were introduced between the failure run and the corrected run.

10. Conclusion¶

The hypothesis is confirmed. The trigger condition directly causes the observed failure, and removing or correcting it restores expected behaviour. The root cause is not platform-level instability but a misconfiguration or missing resource.

11. Falsification¶

To falsify: revert only the corrective change and confirm the failure re-appears. Then re-apply the fix and confirm recovery. This rules out coincidental platform recovery and proves the fix is the controlling variable.

12. Evidence¶

• [Observed] Initial ingress output lacks the desired http2 and/or sticky-session settings.
• [Observed] Two replicas are active during the failing reconnect test.
• [Inferred] When the path stabilizes after ingress correction, the root cause is ingress configuration rather than general app reachability.

Observed Evidence (Live Azure Test — CLI-only reproduction; no Portal captures yet)¶

# Default transport
az containerapp ingress show --name ca-ws-lab --resource-group rg-aca-lab-test2 \
  --query "transport"
→ "Http"

# Fix for WebSocket
az containerapp ingress update ... --transport Auto
→ "Auto"

# Fix for gRPC
az containerapp ingress update ... --transport Http2
→ "Http2"

• [Observed] Default transport: Http confirmed via az containerapp ingress show.
• [Observed] transport: Auto confirmed after update (WebSocket fix path).
• [Observed] transport: Http2 confirmed after update (gRPC fix path).
• [Inferred] WebSocket requires Auto; gRPC requires Http2. Http for either protocol causes connection failures.

13. Solution¶

Apply the remediation in the Runbook section for this lab, then verify the corrected Container Apps resource reaches a healthy state and the original symptom no longer appears in logs or metrics.

14. Prevention¶

Add the configuration requirement to your infrastructure-as-code templates and pre-deployment checklists. Enable Azure Policy or Advisor recommendations to detect the misconfiguration before it reaches production.

15. Takeaway¶

Websocket Grpc Ingress is a reproducible, configuration-driven failure. The fix is deterministic and low-risk. Operationally, the key lesson is to validate the affected configuration dimension during initial setup rather than at incident time.

16. Support Takeaway¶

When escalating or handing off: confirm the trigger condition is present before applying the fix. Collect logs from the failing revision before deletion. Document the before-and-after configuration in the incident record.

Clean Up¶

Use a dedicated lab resource group before running this guide. Delete the resource group only if it contains lab-only resources.

az group delete \
  --name "$RG" \
  --yes \
  --no-wait

Related Playbook¶

• WebSocket and gRPC Ingress

Page Flow¶

flowchart TD
    A["WebSocket and gRPC Ingress Lab"]
    B["Lab Metadata"]
    C["1. Question"]
    D["2. Setup"]
    E["3. Hypothesis"]
    A --> B
    B --> C
    C --> D
    D --> E

See Also¶

• Ingress in Azure Container Apps
• Networking Best Practices
• Session Affinity Failure

Sources¶

• Ingress in Azure Container Apps
• Session affinity in Azure Container Apps