Why the Kudu site for my app service is showing 503 Service Unavailable

3
votes

I am having trouble deploying container to my app service in Azure. In the release pipeline, I saw the following error

[debug][PUT]https://$iagadsca01-cac-app-salesforcedownstream-01:***@iagadsca01-cac-app-salesforcedownstream-01.scm.azurewebsites.net/api/deployments/16801603731950666 [debug]Could not parse response: {} [debug]Response: undefined [debug]Encountered a retriable status code: 503. Message: 'Service Temporarily Unavailable'.

The pipeline will repeat the the above PUT operation for 20 mins and times out eventually.

When I try to open the Kudu site (*.scm) site for my web app, it just gave me a blank page with error

Service Unavailable

I think the scm site should be up regardless my app is running or not? What could cause the scm site to give Service Unavailable error?

1
azureazure-devopsazure-web-app-service
The Kudu site should definitely be up, even in a failed deployment. If you go to your Web App management blade in the Azure Portal and navigate to "Process Explorer", do you see the scm site is running? You could perhaps kill the scm process there and it should reboot. – Rob Reagan
Hey @RobReagan.. thanks for the tip... but the Process Explorer is grey out and when I hover over, it says "this feature is not available for Linux apps" – sean717
Ah. Unfortunately I have zero experience with Linux WebApps, so I likely cannot be of much help. If you recycle the entire WebApp, do you have any luck? If not, my only other suggestion is to FTP into the instance and delete or reset files. – Rob Reagan
@RobReagan.. I restarted the app service a few times already and even deleted / recreated it.. but still no luck... anyways, thanks for the help and next I am going to try to get msft support involved. – sean717
I think you have reached that point. Best of luck. If you don't mind, can you post a resolution after you get things worked out with MSFT? I'm really curious as to how this is resolved. – Rob Reagan

1 Answers

4
votes

This is now solved after I had a support call with MSFT on Teams (my employer has a very high level SLA with MSFT, I was contacted in two hrs after submitting a request), see my summary here:

The support engineer found errors related to vNet for the app service and suggested to disconnect the app service from the vNet. We did that and the issue was solved – the scm site is no longer throw 503 error.

We enabled vNet connection again, and scm site started to give 503 error again. We thought we know the cause is vNet.

Then we kept the vNet connected, and scaled up the app service plan and scaled back – this will cause the app service migrate to another VM instance. After that – the scm remained working!

So we didn’t know if it is vNet which caused problem. The underlying VM probably messed up.