Frequent "Container Stopped" Alerts in App Service for Node.js Container (App Works Fine)

Question

Frequent "Container Stopped" Alerts in App Service for Node.js Container (App Works Fine)

Vivin Kumar 40

Hi Team,

I'm currently running a Node.js application on Azure App Service (Linux) using a custom Docker container. I’ve noticed that I frequently receive alerts indicating "Container stopped", but my application continues to work normally without any visible issues or downtime.

Here are some key points:

App Service Plan Metrics: CPU, memory, and other metrics appear normal.

Application Logs: No crash or failure is observed in the logs.

"Always On" Setting: Enabled in the General Settings of the App Service.

Health: From the user perspective, the app is fully functional, and there are no reported outages.

Despite this, the frequent container stop events are concerning, especially for monitoring and SLA reporting.

Questions:

What could be causing these container stop alerts even though the app continues to run fine?

Is this an expected behavior (e.g., related to scaling, image update checks, or platform-level maintenance)?

How can I further investigate or prevent this from happening?

Any insights or suggestions would be greatly appreciated.

Thanks in advance

Bhargavi Naragani 7,640 Reputation points Moderator

2025-07-10T12:09:30.69+00:00
Hi Vivin Kumar,

It seems like your Node.js application running on Azure App Service (Linux) using a custom Docker container is experiencing frequent "Container stopped" alerts. However, the application continues to run normally without downtime or user-visible issues, and resource metrics like CPU and memory look healthy. This behavior can be confusing, but it is often expected and explainable in the Azure App Service environment.

These container stop logs usually occur due to platform-initiated events such as infrastructure maintenance, OS patching, or VM rebalancing. Azure App Service may restart containers during these operations to ensure platform security and stability. These restarts are handled gracefully and typically don’t impact application availability, especially since you’ve enabled the “Always On” feature. Routine maintenance, restarts, and downtime – Azure App Service

Another common reason for container restarts is related to scaling operations. If your app is configured for scaling (either manually or automatically), Azure may add or remove container instances based on demand, resulting in clean stop/start events that are logged but don’t affect uptime. Scale apps in App Service

Frequent redeployments, even with the same image, can also trigger container restarts. Ensure your CI/CD pipelines or automation processes aren’t unintentionally redeploying the app often. Azure will pull and restart the container for each deployment action. Deploy a custom container to App Service

If you’ve configured a health check endpoint, failed or slow responses can cause Azure to restart containers, thinking they’re unhealthy. While it doesn't appear to be your case given the healthy app status, it's worth reviewing your health check configuration. Configure health checks in App Service

To further investigate these events, you can review Azure Resource Health and Activity Log to determine whether these restarts coincide with infrastructure-level changes or maintenance windows. This helps differentiate between platform-initiated and app-level restarts. Azure Resource Health overview, Azure Monitor Activity Log

To reduce noise from these alerts and avoid unnecessary restarts, ensure your logs and deployment automation are tightly controlled.

Hope this helps, if you have any further concerns or queries, please feel free to reach out to us.
LINGESH WARAN 0 Reputation points

2025-07-11T10:42:36.3366667+00:00

Hello@Bhargavi Naragani Same thing i got error my container has stopped has you said Routine maintenance, restarts, and downtime – Azure App Service and CI/CD and also check my Activiy Log they did not such logs capture and also check the my App plan services and Web App services did not have aslo usage with of 80 percentage limits .it's any alternative check to this error
Bhargavi Naragani 7,640 Reputation points Moderator

2025-07-14T05:06:35.68+00:00
Hi Lee Lingesh,

If your container is unexpectedly stopping without related entries in the Activity Log, even though CPU and memory usage are low, it’s often due to issues internal to the container, such as crashes or health check failures, which don’t show up in standard metrics. To diagnose this:

Enable diagnostic logging for Linux containers under App Service Logs => Application Logging (Filesystem). This captures stdout/stderr and allows you to view real-time output via Log Stream or download logs through the Kudu console under https://<your-app>.scm.azurewebsites.net/api/logs/docker. Enable Diagnostic Logging – Azure App Service

If you have a health check configured, even brief failures can trigger container restarts. Ensure the endpoint reliably returns 200 OK. Configure health checks – App Service

After enabling diagnostics, you'll see any crash logs or exit codes and can identify if a probe or internal error is triggering the stops.
LINGESH WARAN 0 Reputation points

2025-07-15T07:17:13.7133333+00:00

Hello @Bhargavi Naragani ,

As per your suggestion, I checked the App Service logs, and everything appears to be configured correctly. However, I’m still encountering the following error message:

Result: Kudu: XXXX-saas-stg-xxxxx-xxxx-as__b8aa stopped.

Could you please advise on what else might be causing this issue?
Bhargavi Naragani 7,640 Reputation points Moderator

2025-07-15T07:32:53.2866667+00:00

Hi Lee Lingesh,

Since you're not original poster requesting to create new thread for better traction.
Vivin Kumar 40 Reputation points

2025-07-15T07:35:50.9066667+00:00
Hello Bhargavi,

He's my colleague so, you may consider his query
K S H Sultan 0 Reputation points

2025-07-16T08:48:27.6866667+00:00

Hi @Bhargavi Naragani ,
Thank you for answering the queries. As you rightly pointed out, my first conclusion also is application errors like unhandled exceptions, http errors resulting in this... we will check that first and also check Resource Health and Azure Monitor activity log. Vivin and Lingesh are my colleagues too.
Bhargavi Naragani 7,640 Reputation points Moderator

2025-07-17T05:00:38.36+00:00

Hi Sultan K S H Vivin Kumar,

Hope information in comment was helpful. If you have any further concerns or queries, please feel free to post/comment back.
K S H Sultan 0 Reputation points

2025-07-17T09:50:01.31+00:00

Hello Vivin/Lingesh, can you please accept the answer if we can confirm the solutions given.

Answer accepted by question author

0 additional answers

Your answer

LINGESH WARAN 0 Reputation points

2025-07-11T10:42:36.3366667+00:00

Hello@Bhargavi Naragani Same thing i got error my container has stopped has you said Routine maintenance, restarts, and downtime – Azure App Service and CI/CD and also check my Activiy Log they did not such logs capture and also check the my App plan services and Web App services did not have aslo usage with of 80 percentage limits .it's any alternative check to this error
Bhargavi Naragani 7,640 Reputation points Moderator

2025-07-14T05:06:35.68+00:00

Hi Lee Lingesh,

If your container is unexpectedly stopping without related entries in the Activity Log, even though CPU and memory usage are low, it’s often due to issues internal to the container, such as crashes or health check failures, which don’t show up in standard metrics. To diagnose this:

Enable diagnostic logging for Linux containers under App Service Logs => Application Logging (Filesystem). This captures stdout/stderr and allows you to view real-time output via Log Stream or download logs through the Kudu console under https://<your-app>.scm.azurewebsites.net/api/logs/docker. Enable Diagnostic Logging – Azure App Service

If you have a health check configured, even brief failures can trigger container restarts. Ensure the endpoint reliably returns 200 OK. Configure health checks – App Service

After enabling diagnostics, you'll see any crash logs or exit codes and can identify if a probe or internal error is triggering the stops.
LINGESH WARAN 0 Reputation points

2025-07-15T07:17:13.7133333+00:00

Hello @Bhargavi Naragani ,

As per your suggestion, I checked the App Service logs, and everything appears to be configured correctly. However, I’m still encountering the following error message:

Result: Kudu: XXXX-saas-stg-xxxxx-xxxx-as__b8aa stopped.

Could you please advise on what else might be causing this issue?
Bhargavi Naragani 7,640 Reputation points Moderator

2025-07-15T07:32:53.2866667+00:00

Hi Lee Lingesh,

Since you're not original poster requesting to create new thread for better traction.
Vivin Kumar 40 Reputation points

2025-07-15T07:35:50.9066667+00:00

Hello Bhargavi,

He's my colleague so, you may consider his query
K S H Sultan 0 Reputation points

2025-07-16T08:48:27.6866667+00:00

Hi @Bhargavi Naragani ,
Thank you for answering the queries. As you rightly pointed out, my first conclusion also is application errors like unhandled exceptions, http errors resulting in this... we will check that first and also check Resource Health and Azure Monitor activity log. Vivin and Lingesh are my colleagues too.
Bhargavi Naragani 7,640 Reputation points Moderator

2025-07-17T05:00:38.36+00:00

Hi Sultan K S H Vivin Kumar,

Hope information in comment was helpful. If you have any further concerns or queries, please feel free to post/comment back.
K S H Sultan 0 Reputation points

2025-07-17T09:50:01.31+00:00

Hello Vivin/Lingesh, can you please accept the answer if we can confirm the solutions given.

Answer 1

Hi Vivin Kumar, Sure we'll consider your colleague's query

Lee Lingesh, Thanks for checking the App Service logs and sharing the Kudu message:

Result: Kudu: XXXX-saas-stg-xxxxx-xxxx-as__b8aa stopped.

This message generally indicates that the container or instance was stopped, either due to a platform-initiated event, a configuration change, or an internal app rule like Auto-Heal. Since your logs and metrics look fine and you confirmed that there’s no CI/CD trigger or high resource usage, here are the most likely root causes and how to further investigate them:

Azure App Service can automatically restart your app or container if certain conditions are met (e.g., slow requests, memory leaks, HTTP errors). These triggers don’t always show up in the Activity Log.

To check:

Go to your App Service in Azure Portal
Navigate to Diagnose and solve problems => Availability and Performance => Auto-Heal
Review any custom auto-heal rules configured
Disable or adjust them if needed Auto-Heal feature in Azure App Service

Sometimes, Azure may silently restart an instance as part of routine infrastructure maintenance, container image refresh, or proactive performance management. These reboots might not always be visible in the Activity Log but are part of how Azure ensures high availability.

You can confirm this by reviewing the Web App restart history:

Go to your App Service
Click Diagnose and Solve Problems
Under Availability and Performance, select Web App Restarted Diagnose container and app restarts

If you've configured a Health Check endpoint, even brief failures (like high latency or a missed 200 OK) can cause Azure to stop and restart the container. Ensure the endpoint is reliable and fast, especially under load. Configure Health Check in App Service