Random Web App Restarts (Linux)

Evan Hatampour 6 Reputation points
2021-03-03T00:34:47.07+00:00

We got many of these today. Yesterday none. Sometimes we go a month without a single restart. Other times we get a bunch in a day. Here are the details:

File server volume path change was found

Your application was recycled due to an intermittent Azure infrastructure issue while accessing remote file storage. This can happen due to multiple reasons like platform instances getting upgraded or instance(s) experiencing high latencies accessing the remote storage. In case the instance(s) where your application is running is experiencing high latencies accessing remote storage, platform tries to heal your application by switching to different remote storage which is having low latency. This can also cause the application process to restart.

It's always the above. Every time.

Azure App Service
Azure App Service
Azure App Service is a service used to create and deploy scalable, mission-critical web apps.
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  1. SnehaAgrawal-MSFT 19,436 Reputation points
    2021-03-03T08:47:51.693+00:00

    Thanks for asking question! There is possibility that there is a high latency on the I/O to the storage. The high latency can cause a failover to read only storage, and then the container tries to write to the logfiles it fails. If this happens on startup or restart, then the container fails and Azure will restart it again in a few seconds.

    Below are the steps you may use to monitor the I/O operations:

    • From Azure Portal browse to your app, and open the “metrics” blade, you can aggregate the IO related metrics per app and setup an alert rule accordingly to be notified when the IO operations exceeds a certain limit

    73713-demo4.png

    • You can find the meaning of each metric on this link

    Could you please confirm on app service plan. Scaling up might be helpful. As then app service plan will have more resource after scaling up and this will lower the I/O latency and improve the problem with the restarts.

    Also, AutoHeal recycles the worker process for your app based on settings you choose (like configuration changes, requests, memory-based limits, or the time needed to execute a request). AutoHeal automatically restarts the webapp.

    Please let us know if there is further query or issue not resolved.

    1 person found this answer helpful.