I do have a Docker container running a .net core 2 app.
The logging is configured using this code in Program.cs
public static IWebHostBuilde
I've been cursing this for a good while, and eventually found something that works for me.
First I enabled filesystem logging as per @dima_horror's answer.
Next I ran a command-line az webapp log tail --name myApp --resource-group myRg
That now seems to give me useful output (it gave me nothing prior to enabling filesystem logging).
Firstly you need to enable container logs
[App Service] -> Monitoring -> App Service logs
Then you can see container logs in [App Service] -> Monitoring -> Log stream
UPD
Also you can find logs in KUDU
Then "Current Docker Logs"
To add to the answers, if you're having trouble with deploying the image in your App Service and need logs for that specifically, you can get the docker logs for the provisioning phase of your container under Deployment Center, e.g.:
I have the same exact issue, the App Service container logs is generic and vague. This is not the same logs that Docker shows us whenever we run a container.
17/02/2020 08:59:25.186 INFO - Site: tutorial-api - Start container succeeded. Container: f8bfa7e27680c0e9551c6157f9d1c8a73c9a3e739b4f15de8586ce52809798d3
17/02/2020 08:59:30.675 INFO - Site: tutorial-api - Application Logging (Filesystem): On
17/02/2020 08:59:44.106 INFO - Site: tutorial-api - Waiting for container to be ready
17/02/2020 08:59:49.116 INFO - Site: tutorial-api - Container has exited
17/02/2020 08:59:49.117 ERROR - Site: tutorial-api - Container could not be started
17/02/2020 08:59:49.120 INFO - Site: tutorial-api - Purging after container failed to start
17/02/2020 08:59:49.120 ERROR - Site: tutorial-api - Unable to start container. Error message: Container could not be started: tutorial-api_20
"Unable to start container, container couldn't be started"
Wow! Azure just told me every 60 seconds a minute has passed.
I understand that this is production environment, but you got to give us something!
Out of frustration, I decided to run same image in a Azure Container Instance resource, there it shows you the same detailed logs that Docker provides (see screenshot below)
Now that's what I'm talking about!
Using the error logs in Azure Container Instance, I found out that my App Service couldn't access the Sql Server resource (even though they are within the same resource group). I simply enabled the Sql Server resource to be accessed within the same resource group
Have you checked the logs in container settings? I followed this guide to deploy a container to Azure web app.