Azure App Service shared hosting fail container startup

Question

I have an Azure App Service running my own docker image based on PHP (mcr.microsoft.com/appsvc/php:7.4-apache_20201229.1)

Deploying to the service works and the website runs as expected (WEBSITES_ENABLE_APP_SERVICE_STORAGE : false)

I want to be able to use persistent storage to save data from fails / web app restarts ...

I wanted to use the in-built persisted storage and set the application setting WEBSITES_ENABLE_APP_SERVICE_STORAGE to true, use docker compose like that :

version: '3.3'

services:
   back:
     image: XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
     volumes:
      - ${WEBAPP_STORAGE_HOME}/site/wwwroot:/var/www/html
     ports:
       - "8000:80"
     restart: always

However after changing this setting and stop/start the web app, the container no longer starts successfully and gives no reason why.

The logs I get are below:

2021-06-17T23:49:43.847Z INFO  - Starting container for site
2021-06-17T23:49:43.847Z INFO  - docker run -d -p 8081:80 --name XXXXXXXXXXXXXXX -e WEBSITE_CORS_ALLOWED_ORIGINS=XXXXXXXXX -e WEBSITE_CORS_SUPPORT_CREDENTIALS=True -e WEBSITES_ENABLE_APP_SERVICE_STORAGE=true -e WEBSITE_SITE_NAME=XXXXXXXXXXXXXXXXX -e WEBSITE_AUTH_ENABLED=False -e WEBSITE_ROLE_INSTANCE_ID=0 -e WEBSITE_HOSTNAME=XXXXXXXXXXXXXXX -e WEBSITE_INSTANCE_ID=bd0010bcc7f2a648cafc4bcac18f1660692939e3ec29400aeb60d8a3d788c1c3 -e HTTP_LOGGING_ENABLED=1 XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX  
2021-06-17T23:53:34.572Z ERROR - multi-container unit was not started successfully

What is WEBSITES_ENABLE_APP_SERVICE_STORAGE breaking about my container? I have bash access to the running kudu instance (the ssh break also) and i don't see any file from my application

Are there any logs that would allow me to view what is failing or anything I've not considered with the WEBSITES_ENABLE_APP_SERVICE_STORAGE setting?

Thanks

EDIT :

when putting only WEBSITES_ENABLE_APP_SERVICE_STORAGE = true , and adding -v ${WEBAPP_STORAGE_HOME}/site/wwwroot/storage:/storage in startup command , the content of wwwroot will be deleted and my docker image will be replaced by

2021-06-18T08:07:54.534Z INFO  - docker run -d -p 2301:80 --name XXXXXXXXXXXXXX_0_f194ab38 -e WEBSITE_CORS_ALLOWED_ORIGINS=https://XXXXXXXXXXX.azurewebsites.net -e WEBSITE_CORS_SUPPORT_CREDENTIALS=True -e WEBSITES_ENABLE_APP_SERVICE_STORAGE=true -e WEBSITE_SITE_NAME=XXXXXXXXXXXX -e WEBSITE_AUTH_ENABLED=False -e PORT=80 -e WEBSITE_ROLE_INSTANCE_ID=0 -e WEBSITE_HOSTNAME=XXXXXXXXXXXXXXXXXXXXXXXXXXX.azurewebsites.net -e WEBSITE_INSTANCE_ID=bd0010bcc7f2a648cafc4bcac18f1660692939e3ec29400aeb60d8a3d788c1c3 -e HTTP_LOGGING_ENABLED=1 **IMAGE** -v ${WEBAPP_STORAGE_HOME}/site/wwwroot/storage:/storage 

2021-06-18T08:07:55.414Z INFO  - Starting container for site
2021-06-18T08:07:55.415Z INFO  - docker run -d -p 4849:8081 --name XXXXXXXXXXXXXXXXXX_0_f194ab38_middleware -e WEBSITE_CORS_ALLOWED_ORIGINS=https://XXXXXXXXXXXXXX -e WEBSITE_CORS_SUPPORT_CREDENTIALS=True -e WEBSITES_ENABLE_APP_SERVICE_STORAGE=true -e WEBSITE_SITE_NAME=xXXXXXXXXXXX -e WEBSITE_AUTH_ENABLED=False -e WEBSITE_ROLE_INSTANCE_ID=0 -e WEBSITE_HOSTNAME=XXXXXXXXXXXXXX.azurewebsites.net -e WEBSITE_INSTANCE_ID=bd0010bcc7f2a648cafc4bcac18f1660692939e3ec29400aeb60d8a3d788c1c3 -e HTTP_LOGGING_ENABLED=1 appsvc/middleware:1.4.5 /Host.ListenUrl=http://0.0.0.0:8081 /Host.DestinationHostUrl=http://172.16.27.2:80 /Host.UseFileLogging=true

Rohit Tatiya Rohit Tatiya · Accepted Answer · 2021-06-19T20:07:04

The appsetting WEBSITES_ENABLE_APP_SERVICE_STORAGE use to mount a location in Azure Storage to the /home mount point.

WEBAPP_STORAGE_HOME is an environment variable in App Service that is mapped to persistent storage for your app.

https://docs.microsoft.com/en-us/archive/blogs/waws/things-you-should-know-web-apps-and-linux#if-your-site-doesnt-start-check-the-docker-logapplies-to-web-app-for-containers.

You can also make use of app service inbuild "diagnose and solve problems" blade to better understand why container crash or unable to start.

Azure App Service shared hosting fail container startup

1 Answers