Request for Guidance: JAVA Uninstallation in Azure Function App (B3 Plan) and Recommendations for Production Stability

Question

Request for Guidance: JAVA Uninstallation in Azure Function App (B3 Plan) and Recommendations for Production Stability

Vishal Bhalabar 20

[Azure Environment]

Azure function app with B3 app service plan. (Hosting plan: App service plan)

[Functionality]

There is a one CSV file which has storage container and Search index mapping. Function app reads this CSV. Reads documents present on storage container and by using Azure Open AI's text embedding model, saves embedding into Search index.

Note: For processing .doc and .xls files, app needs JAVA to be installed on system.

[Deployment]

Deployed this function app from Visual studio code. It runs every 5 mints.

[Post Deployment]

Restarted function app after deployment. Connected to SSH and installed JAVA (apt-get update && apt-get install -y default-jdk). Verified java is installed.

[Issue]

After few days, it’s been observed that JAVA is uninstalled.

1.Could you please guide us on what could be the reason/cause?

2.How can we check/verify the cause?

3.What is recommended for Production use? (Any other app service plan?)

4.How can we avoid this in Production going forward?

Pravallika KV 17,025 Reputation points Microsoft External Staff Moderator

2025-11-05T01:42:21.8366667+00:00

Hi Vishal Bhalabar,

Following up to see if the above response was helpful. Please do let me know if you need any further assistance on this.

Thanks
Vishal Bhalabar 20 Reputation points

2025-11-05T13:16:59.0966667+00:00
Hi Pravallika KV:

Thank you for feedback.

More Details:

While creating app service, selected Publish as Code (not container), OS: Linux, Runtime stack: Python 3.11.

Function app's programming language is Python. Java/JDK package is required to processes specific file types (.doc and .xls).

Could you please give more insights on how to check specific log for this cause in Application Insights and java configuration to persist through restart?

Thank you in advanced.
Vishal Bhalabar 20 Reputation points

2025-11-06T13:34:23.9066667+00:00

PFA screenshot for trace log for message 'starting host' or 'loading function metadata'.

Does it means it got restarted on 6 OCT and 20 OCT? (FYI, We have not manually restarted this function app.)
Pravallika KV 17,025 Reputation points Microsoft External Staff Moderator

2025-11-06T13:51:31.56+00:00
Vishal Bhalabar,.

Yes, In Azure Function Apps, these log entries “Starting host” and “Loading function metadata” appear during host startup, i.e., when the Function runtime process is initialized.

Starting host -The function host process is booting up, this happens on cold start, restart, scale-in/out, or platform update.

Loading functions metadata- The runtime is enumerating your function definitions from function.json and loading Python entry points. This happens immediately after host start.

Could you please give more insights on how to check specific log for this cause in Application Insights and java configuration to persist through restart?

Open your Function App => Application Insights => Logs:

Run below query:

traces | where timestamp > ago(1h) | where message contains "java" or message contains "jdk" or message contains "error" | project timestamp, message | order by timestamp desc

Check Log Stream:

Go to Function App => Log Stream.

Check during cold start, JVM-related errors show up.
Vishal Bhalabar 20 Reputation points

2025-11-07T09:27:57.7233333+00:00

Hi Pravallika KV:

Thank you for the feedback.

Could you please share details on below

Q#1 : Can we get any exact reason for function app restart? Any way/logs to find it out?

Q#2 : We checked the result for given query and found instances where JAVA related error occurred.

If we upgrade it to Functions Premium hosting plan , will this make sure JDK is persisted after function app restart?

Please note: Function app's runtime is Python. Java is needed for one of the feature of function app (to read .doc and .xls files)
Vishal Bhalabar 20 Reputation points

2025-11-10T04:43:12.11+00:00
Hi Pravallika KV:

If an automatic reboot operation is performed by Microsoft, will the administrator/someone receive a report by email after the operation is completed ?

For Premium Plan - Does Microsoft provides any notification for restart due to platform updates/cold restart ?
Pravallika KV 17,025 Reputation points Microsoft External Staff Moderator

2025-11-10T05:21:18.33+00:00
Hi Vishal Bhalabar,

Microsoft does not automatically send a post-restart email unless you configure Service Health alerts.

With Premium Plan, you can receive notifications for planned platform updates and restarts via Service Health alerts, but by default, no automatic email is sent for routine restarts.
Vishal Bhalabar 20 Reputation points

2025-11-10T06:29:03.87+00:00
Hi Pravallika KV

With Premium Plan, you can receive notifications for planned platform updates and restarts via Service Health alerts, but by default, no automatic email is sent for routine restarts

Is it same of Standard plan (S3) as well ?

Is there any way to check if that restart (e.g. routine restart i.e. starting host in logs), has occurred due to MS underlying platform other than looking at the logs?
Pravallika KV 17,025 Reputation points Microsoft External Staff Moderator

2025-11-14T04:23:49.6433333+00:00
Vishal Bhalabar,

Apologies for the delay in response.

Yes, the situation is the same for Standard plan (S3) as Premium.

Planned maintenance notifications are available through Service Health, but routine restarts are not automatically emailed.

Azure does not provide a direct "restart alert" for routine platform restarts. But you have a few options:

Azure Resource Health

Go to Resource Health for the App Service.

Shows if the platform performed an action affecting your instance (e.g., "App Restarted due to platform update").

Kudu / SCM Endpoint

Navigate to https://<appname>.scm.azurewebsites.net/ProcessExplorer

Shows process start times; you can notice if a worker process was restarted.

Alerts

While there’s no default “restart alert,” you can create custom alerts:

Track uptime metrics or heartbeat signals from your application.

If a process disappears or a heartbeat fails, trigger an alert.

1 answer

Your answer

Pravallika KV 17,025 Reputation points Microsoft External Staff Moderator

2025-11-05T01:42:21.8366667+00:00

Hi Vishal Bhalabar,

Following up to see if the above response was helpful. Please do let me know if you need any further assistance on this.

Thanks
Vishal Bhalabar 20 Reputation points

2025-11-05T13:16:59.0966667+00:00

Hi Pravallika KV:

Thank you for feedback.

More Details:

While creating app service, selected Publish as Code (not container), OS: Linux, Runtime stack: Python 3.11.

Function app's programming language is Python. Java/JDK package is required to processes specific file types (.doc and .xls).

Could you please give more insights on how to check specific log for this cause in Application Insights and java configuration to persist through restart?

Thank you in advanced.
Vishal Bhalabar 20 Reputation points

2025-11-06T13:34:23.9066667+00:00

PFA screenshot for trace log for message 'starting host' or 'loading function metadata'.

Does it means it got restarted on 6 OCT and 20 OCT? (FYI, We have not manually restarted this function app.)
Pravallika KV 17,025 Reputation points Microsoft External Staff Moderator

2025-11-06T13:51:31.56+00:00

Vishal Bhalabar,.

Yes, In Azure Function Apps, these log entries “Starting host” and “Loading function metadata” appear during host startup, i.e., when the Function runtime process is initialized.

Starting host -The function host process is booting up, this happens on cold start, restart, scale-in/out, or platform update.

Loading functions metadata- The runtime is enumerating your function definitions from function.json and loading Python entry points. This happens immediately after host start.

Could you please give more insights on how to check specific log for this cause in Application Insights and java configuration to persist through restart?

Open your Function App => Application Insights => Logs:

Run below query:

traces | where timestamp > ago(1h) | where message contains "java" or message contains "jdk" or message contains "error" | project timestamp, message | order by timestamp desc

Check Log Stream:

Go to Function App => Log Stream.

Check during cold start, JVM-related errors show up.
Vishal Bhalabar 20 Reputation points

2025-11-07T09:27:57.7233333+00:00

Hi Pravallika KV:

Thank you for the feedback.

Could you please share details on below

Q#1 : Can we get any exact reason for function app restart? Any way/logs to find it out?

Q#2 : We checked the result for given query and found instances where JAVA related error occurred.

If we upgrade it to Functions Premium hosting plan , will this make sure JDK is persisted after function app restart?

Please note: Function app's runtime is Python. Java is needed for one of the feature of function app (to read .doc and .xls files)
Vishal Bhalabar 20 Reputation points

2025-11-10T04:43:12.11+00:00

Hi Pravallika KV:

If an automatic reboot operation is performed by Microsoft, will the administrator/someone receive a report by email after the operation is completed ?

For Premium Plan - Does Microsoft provides any notification for restart due to platform updates/cold restart ?
Pravallika KV 17,025 Reputation points Microsoft External Staff Moderator

2025-11-10T05:21:18.33+00:00

Hi Vishal Bhalabar,

Microsoft does not automatically send a post-restart email unless you configure Service Health alerts.

With Premium Plan, you can receive notifications for planned platform updates and restarts via Service Health alerts, but by default, no automatic email is sent for routine restarts.
Vishal Bhalabar 20 Reputation points

2025-11-10T06:29:03.87+00:00

Hi Pravallika KV

With Premium Plan, you can receive notifications for planned platform updates and restarts via Service Health alerts, but by default, no automatic email is sent for routine restarts

Is it same of Standard plan (S3) as well ?

Is there any way to check if that restart (e.g. routine restart i.e. starting host in logs), has occurred due to MS underlying platform other than looking at the logs?
Pravallika KV 17,025 Reputation points Microsoft External Staff Moderator

2025-11-14T04:23:49.6433333+00:00

Vishal Bhalabar,

Apologies for the delay in response.

Yes, the situation is the same for Standard plan (S3) as Premium.

Planned maintenance notifications are available through Service Health, but routine restarts are not automatically emailed.

Azure does not provide a direct "restart alert" for routine platform restarts. But you have a few options:

Azure Resource Health

Go to Resource Health for the App Service.

Shows if the platform performed an action affecting your instance (e.g., "App Restarted due to platform update").

Kudu / SCM Endpoint

Navigate to https://<appname>.scm.azurewebsites.net/ProcessExplorer

Shows process start times; you can notice if a worker process was restarted.

Alerts

While there’s no default “restart alert,” you can create custom alerts:

Track uptime metrics or heartbeat signals from your application.

If a process disappears or a heartbeat fails, trigger an alert.

Answer 1

Hi Vishal Bhalabar,

Thanks for reaching out to Microsoft Q&A.

Java getting uninstalled could be because of App Service Plan Limitations and environment scope.

The B3 pricing plan might have restrictions that do not preserve custom configurations or installations across restarts. App Service environments can sometimes loose installed dependencies if the underlying platform is reset or scaled.
If the Java installation was done under a different scope i.e., in a temporary container, it might not be retained after restarting the app.

Could you please guide us on what could be the reason/cause?

Enable Application Insights in your Function App. Review the logs to see any errors or messages related to Java installation after a restart. Look for events related to environment changes.
Ensure that the settings for Java are correctly configured to persist through restarts. You can check this in the Azure Portal under App Service settings.

Recommendations for Production Use:

Upgrade to a Premium Plan or Elastic Premium Plan for a more stable hosting option for Java applications. These plans provide better performance and reliability for Java applications and allow you to configure your environment more persistently.

How to Avoid This in Production?

Instead of manually installing Java, use the built-in Java offered by Azure for the Function Apps. Select the latest version available in the Azure Portal.
If you require specific Java versions or configurations, consider using a Docker container where you can guarantee the environment's state across deployments.

Save your necessary configurations or installations into Azure Blob Storage or Azure Files that can be accessed and restored whenever needed.

Azure Functions Java developer guide

Java on App Service configuration guide

Hope it helps!

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Request for Guidance: JAVA Uninstallation in Azure Function App (B3 Plan) and Recommendations for Production Stability

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Your answer