This is a quick sample on how to prep an nginx image to run in Azure App Service for Linux as a Custom Image.
The important piece is the activation of the SSH daemon if you want to use the SSH debug capabilities of the Azure Portal. See Dockerfile for details.
docker run --name hello-world -p 8000:2222 -t myacr.azurecr.io/hello-world:v1.0.0
ssh -c aes256-cbc -p 8000 root@localhost