409 Conflict: Could not write to local resource 'D:\home\site\wwwroot\web.config' due to error 'Access to the path is denied.'.

Issues/Errors

409 Conflict: Could not write to local resource 'D:\home\site\wwwroot\web.config' due to error 'Access to the path is denied.'.

Not able to Delete and Stop continuous web jobs from Portal/Kudu.

Cause of the Issue

The above issues/errors occur when we are not allowed to perform any write operations on wwwroot folder.

The application setting ‘WEBSITE_RUN_FROM_PACKAGE=1’ of the App Service makes the wwwroot folder of the application as read-only.

If the setting is available in the application settings of the App Service then we will get 409 conflict error whenever we try to add/edit any files to the wwwroot folder from App Service Editor or Kudu console.

When Deleting/Stopping a web job, it tries to add a file disable.job file to the job folder. If the Web Job is deployed to App_Data folder of wwwroot folder of the application then adding of disable.job file to the job folder i.e. App_Data is not supported and hence web job delete/stop operation from Azure Portal/kudu will be unsuccessful.

When does the setting ‘WEBSITE_RUN_FROM_PACKAGE=1’ get added?

 Usually the setting is added when Run from package deployment is performed to App Service.

Run from Package deployment means application code will be available as a Zip deployment package in the d:\home\data\SitePackages (instead of wwwroot folder) and the zip gets mounted on wwwroot as a read-only file system.

Deploying from DevOps using App Service Deploy task version 4.0, if no deployment method is selected, it auto selects the best suitable deployment method based on the build artifact generated.

If the artifact generated is Zip file and App Service Deploy Task version is 4.0 then most probably it auto-select Run from Package deployment method (if no deployment method is selected manually) and add the setting ‘WEBSITE_RUN_FROM_PACKAGE=1’ making wwwroot folder as read-only.

More details about Run from package deployment can be found on the Url:

https://github.com/Azure/app-service-announcements/issues/84

Solution

Deploy the application/web job using other deployment method i.e. MSDeploy, which change the setting value to 0 and make wwwroot folder writable.

Deleting the setting ‘WEBSITE_RUN_FROM_PACKAGE’ or changing the setting value to 0.

Note: Deleting the setting ‘WEBSITE_RUN_FROM_PACKAGE’ or changing the setting value to 0 implies the application code will now be pointed to wwwroot folder, so before changing the value to 0 make sure you  application code is not pointing to d:\home\data\SitePackages so as to avoid the situation where wwwroot folder end up having no files.