Migrate custom software to Azure App Service using a custom container

Choose a custom container platform

Linux container Windows container

Azure App Service provides pre-defined application stacks, like ASP.NET or Node.js, on Windows. These application stacks run on IIS. The preconfigured Windows environment locks down the operating system from:

• Administrative access.
• Software installations.
• Changes to the global assembly cache.

For more information, see Operating system functionality on Azure App Service.

You can deploy a custom-configured Windows image from Visual Studio to make OS changes that your app needs. This makes it easy to migrate an on-premises app that requires a custom OS and software configuration. This tutorial demonstrates how to migrate to App Service an ASP.NET app that uses custom fonts installed in the Windows font library. You deploy a custom-configured Windows image from Visual Studio to Azure Container Registry and then run it in App Service.

Prerequisites

To complete this tutorial:

• Sign up for a Docker Hub account.
• Install Docker for Windows.
• Configure Docker to run Windows containers.
• Install Visual Studio 2022 with the ASP.NET and web development and Azure development workloads. If you've installed Visual Studio 2022 already:
  • Install the latest updates in Visual Studio by selecting Help > Check for Updates.
  • Add the workloads in Visual Studio by selecting Tools > Get Tools and Features.

Set up the app locally

Download the sample

In this step, you set up the local .NET project.

• Download the sample project.
• Extract (unzip) the custom-font-win-container-master.zip file.

The sample project contains a simple ASP.NET application that uses a custom font that's installed into the Windows font library. It's not necessary to install fonts. However, the sample is an example of an app that's integrated with the underlying OS. To migrate such an app to App Service, you either rearchitect your code to remove the integration, or migrate it as-is in a custom Windows container.

Install the font

In Windows Explorer, navigate to custom-font-win-container-master/CustomFontSample, right-click FrederickatheGreat-Regular.ttf, and select Install.

This font is publicly available from Google Fonts.

Run the app

Open the custom-font-win-container-master/CustomFontSample.sln file in Visual Studio.

Select Ctrl+F5 to run the app without debugging. The app is displayed in your default browser.

As the app uses an installed font, the app can't run in the App Service sandbox. However, you can deploy it using a Windows container instead, because you can install the font in the Windows container.

Configure Windows container

In Solution Explorer, right-click the CustomFontSample project and select Add > Container Orchestration Support.

Select Docker Compose > OK.

Your project is now set to run in a Windows container. A Dockerfile is added to the CustomFontSample project, and a docker-compose project is added to the solution.

From the Solution Explorer, open Dockerfile.

You need to use a supported parent image. Change the parent image by replacing the FROM line with the following code:

Dockerfile

FROM mcr.microsoft.com/dotnet/framework/aspnet:4.7.2-windowsservercore-ltsc2019

At the end of the file, add the following line and save the file:

Dockerfile

RUN ${source:-obj/Docker/publish/InstallFont.ps1}

You can find InstallFont.ps1 in the CustomFontSample project. It's a simple script that installs the font. You can find a more complex version of the script in the PowerShell Gallery.

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To test the Windows container locally, ensure that Docker is started on your local machine.

Publish to Azure Container Registry

Azure Container Registry can store your images for container deployments. You can configure App Service to use images that are hosted in Azure Container Registry.

Open the publish wizard

In the Solution Explorer, right-click the CustomFontSample project and select Publish.

Create and publish the registry

In the publish wizard, select Container Registry > Create New Azure Container Registry > Publish.

Sign in with an Azure account

In the Create a new Azure Container Registry dialog, select Add an account, and then sign in to your Azure subscription. If you're already signed in, select the account containing the desired subscription from the dropdown.

Configure the registry

Configure the new container registry by using the suggested values in the following table as a guide. When finished, select Create.

Setting	Suggested value
DNS Prefix	Keep the generated registry name, or change it to another unique name.
Resource Group	Select New, type myResourceGroup, and select OK.
SKU	Basic. For more information, see Pricing tiers.
Registry Location	West Europe

A terminal window opens and displays the image deployment progress. Wait for the deployment to complete.

Sign in to Azure

Sign in to the Azure portal.

Create a web app

From the left menu, select Create a resource > Web > Web App for Containers.

Configure app basics

On the Basics tab, configure the settings according to the following table. Then select Next: Docker.

Setting	Suggested value
Subscription	Make sure the correct subscription is selected.
Resource Group	Select Create new, type myResourceGroup, and select OK.
Name	Type a unique name. The URL of the web app is https://<app-name>.azurewebsites.net, where <app-name> is your app name.
Publish	Docker Container
Operating System	Windows
Region	West Europe
Windows Plan	Select Create new, type myAppServicePlan, and select OK.

Your Basics tab should look like this:

Configure the Windows container

On the Docker tab, configure your custom Windows container as shown in the following table, and then select Review + create.

Setting	Suggested value
Image Source	Azure Container Register
Registry	Select the registry you created earlier.
Image	customfontsample
Tag	latest

Complete app creation

Select Create and wait for Azure to create the required resources.

Browse to the web app

When the deployment is complete, a notification box is displayed.

1. Select Go to resource.

2. In the app page, select the link under URL.

A new browser page is opened to the following page:

Wait a few minutes and try again, until you get the homepage with the font you expect:

Congratulations! You've migrated an ASP.NET application to Azure App Service in a Windows container.

View the container start-up logs

It might take some time for the Windows container to load. To see the progress, go to the following URL. (Replace <app-name> with the name of your app.)

https://<app-name>.scm.azurewebsites.net/api/logstream

The streamed logs look like this:

14/09/2018 23:16:19.889 INFO - Site: fonts-win-container - Creating container for image: customfontsample20180914115836.azurecr.io/customfontsample:latest.
14/09/2018 23:16:19.928 INFO - Site: fonts-win-container - Create container for image: customfontsample20180914115836.azurecr.io/customfontsample:latest succeeded. Container Id 329ecfedbe370f1d99857da7352a7633366b878607994ff1334461e44e6f5418
14/09/2018 23:17:23.405 INFO - Site: fonts-win-container - Start container succeeded. Container: 329ecfedbe370f1d99857da7352a7633366b878607994ff1334461e44e6f5418
14/09/2018 23:17:28.637 INFO - Site: fonts-win-container - Container ready
14/09/2018 23:17:28.637 INFO - Site: fonts-win-container - Configuring container
14/09/2018 23:18:03.823 INFO - Site: fonts-win-container - Container ready
14/09/2018 23:18:03.823 INFO - Site: fonts-win-container - Container start-up and configuration completed successfully

Azure App Service uses the Docker container technology to host both built-in images and custom images. To see a list of built-in images, run the Azure CLI command, 'az webapp list-runtimes --os linux'. If those images don't satisfy your needs, you can build and deploy a custom image.

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Your container should target the x86-64 architecture. ARM64 is not supported.

In this tutorial, you learn how to:

• Push a custom Docker image to Azure Container Registry.
• Deploy the custom image to App Service.
• Configure environment variables.
• Pull the image into App Service by using a managed identity.
• Access diagnostic logs.
• Enable CI/CD from Azure Container Registry to App Service.
• Connect to the container by using SSH.

Completing this tutorial incurs a small charge in your Azure account for the container registry and can incur more costs if you host the container for longer than a month.

Set up your initial environment

This tutorial requires version 2.0.80 or later of the Azure CLI. If you're using Azure Cloud Shell, the latest version is already installed.

• Have an Azure account with an active subscription. Create an account for free.

• Use the Bash environment in Azure Cloud Shell. For more information, see Quickstart for Bash in Azure Cloud Shell.

  

• If you prefer to run CLI reference commands locally, install the Azure CLI. If you're running on Windows or macOS, consider running Azure CLI in a Docker container. For more information, see How to run the Azure CLI in a Docker container.

  • If you're using a local installation, sign in to the Azure CLI by using the az login command. To finish the authentication process, follow the steps displayed in your terminal. For other sign-in options, see Sign in with the Azure CLI.

  • When you're prompted, install the Azure CLI extension on first use. For more information about extensions, see Use extensions with the Azure CLI.

  • Run az version to find the version and dependent libraries that are installed. To upgrade to the latest version, run az upgrade.

• Install Docker, which you use to build Docker images. Installing Docker might require a computer restart.

After installing Docker, open a terminal window and verify that the docker is installed:

Bash

docker --version

Clone or download the sample app

You can obtain the sample for this tutorial via git clone or download.

Clone with Git

Clone the sample repository:

terminal

git clone https://github.com/Azure-Samples/docker-django-webapp-linux.git --config core.autocrlf=input

Ensure that you include the --config core.autocrlf=input argument to guarantee proper line endings in files that are used inside the Linux container.

Then navigate to the folder:

terminal

cd docker-django-webapp-linux

Download from GitHub

Instead of using git clone, you can visit https://github.com/Azure-Samples/docker-django-webapp-linux and select Code > Local > Download ZIP.

Unpack the ZIP file into a folder named docker-django-webapp-linux.

Then open a terminal window in the docker-django-webapp-linux folder.

(Optional) Examine the Docker file

This is the file in the sample that's named Dockerfile. It describes the Docker image and contains configuration instructions.

Dockerfile

FROM tiangolo/uwsgi-nginx-flask:python3.6

RUN mkdir /code
WORKDIR /code
ADD requirements.txt /code/
RUN pip install -r requirements.txt --no-cache-dir
ADD . /code/

# ssh
ENV SSH_PASSWD "root:Docker!"
RUN apt-get update \
        && apt-get install -y --no-install-recommends dialog \
        && apt-get update \
 && apt-get install -y --no-install-recommends openssh-server \
 && echo "$SSH_PASSWD" | chpasswd 

COPY sshd_config /etc/ssh/
COPY init.sh /usr/local/bin/

RUN chmod u+x /usr/local/bin/init.sh
EXPOSE 8000 2222

#CMD ["python", "/code/manage.py", "runserver", "0.0.0.0:8000"]
ENTRYPOINT ["init.sh"]

• The first group of commands installs the app's requirements in the environment.
• The second group of commands creates an SSH server to provide improved-security communication between the container and the host.
• The last line, ENTRYPOINT ["init.sh"], invokes init.sh to start the SSH service and Python server.

Build and test the image locally

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Docker Hub has quotas on the number of anonymous pulls per IP and the number of authenticated pulls per free user. If you notice your pulls from Docker Hub are being limited, try docker login if you're not already logged in.

1. Run the following command to build the image:

   Bash

   docker build --tag appsvc-tutorial-custom-image .
   

2. Test that the build works by running the Docker container locally:

   Bash

   docker run -it -p 8000:8000 appsvc-tutorial-custom-image
   

   This docker run command specifies the port with the -p argument and includes the name of the image. -it lets you stop it with Ctrl+C.

   Näpunäide

   If you're running on Windows and see the error standard_init_linux.go:211: exec user process caused "no such file or directory", the init.sh file contains CRLF line endings instead of the expected LF endings. This error happens if you used Git to clone the sample repository but omitted the --config core.autocrlf=input parameter. In this case, clone the repository again with the --config argument. You might also see the error if you edited init.sh and saved it with CRLF endings. In this case, save the file again with LF endings only.

3. Browse to http://localhost:8000 to verify that the web app and container are functioning correctly.

   

I. Create a user-assigned managed identity

App Service can use either a default managed identity or a user-assigned managed identity to authenticate with a container registry. In this tutorial, you'll use a user-assigned managed identity.

Azure CLI

1. Run the az group create command to create a resource group:

   Azure CLI

   az group create --name msdocs-custom-container-tutorial --location westeurope
   

   You can change the --location value to specify a region near you.

2. Create a managed identity in the resource group:

   Azure CLI

   az identity create --name myID --resource-group msdocs-custom-container-tutorial
   

Azure portal

I.A. In the Azure portal:

1. Type "Managed Identities" in the search bar at the top of the Azure portal.
2. Select the item labeled Managed Identities under the Services heading.
3. Select Create. You can also navigate to the creation wizard directly.

I.B. In the create wizard:

1. In Subscription, select the subscription you want to create your resources in.
2. In Resource group, select Create new, type the name msdocs-custom-container-tutorial for the resource group, then select OK.
3. In Region, select West Europe, or a region near you.
4. In Name, type myID.

I.C.

1. Select the Review + create tab.
2. Select Create.

I.D. When the creation of the identity is complete, you can open its management page by selecting Go to resource.

II. Create a container registry

Azure CLI

1. Create a container registry by using the following az acr create command. Replace <registry-name> with a unique name for your registry. The name must contain only letters and numbers, and must be unique across all of Azure.

   Azure CLI

   az acr create --name <registry-name> --resource-group msdocs-custom-container-tutorial --sku Basic --admin-enabled true
   

   The --admin-enabled parameter lets you push images to the registry using administrative credentials.

2. Retrieve the administrative credentials by running the az credential acr show command:

   Azure CLI

   az acr credential show --resource-group msdocs-custom-container-tutorial --name <registry-name>
   

   The JSON output of this command provides two passwords along with the registry's user name.

Azure portal

II.A. In the Azure portal:

1. Type "Container registries" in the search bar at the top of the Azure portal.
2. Select the item labeled Container registries under the Services heading.
3. Select Create. You can also navigate to the creation wizard directly.

II.B. In the creation wizard:

1. In Subscription, select the subscription you used earlier.
2. In Resource group, select msdocs-custom-container-tutorial.
3. In Registry name, type a unique name for your container registry.
4. In Location, select West Europe, or the same region as your managed identity.
5. In SKU, select Basic.

II.C.

1. Select the Review + create tab.
2. Select Create.

II.D. When the creation of the container registry is complete, open its management page by selecting Go to resource.

II.E. In the left navigation menu:

1. Select Access keys.
2. In Admin user, select Enabled.
3. Copy the values for Login server, Username, and password. You'll use them in the next step to sign into the registry and push a docker image.

III. Push the sample image to Azure Container Registry

In this section, you push the image to Azure Container Registry, which will be used by App Service later.

1. From the local terminal where you built the sample image, use the docker login command to sign in to the container registry:

   Bash

   docker login <registry-name>.azurecr.io --username <registry-username>
   

   Replace <registry-name> and <registry-username> with values from the previous steps. When prompted, type in one of the passwords from the previous section.

   You use the same registry name in all the remaining steps of this section.

2. When the sign-in is successful, tag your local Docker image to the registry:

   Bash

   docker tag appsvc-tutorial-custom-image <registry-name>.azurecr.io/appsvc-tutorial-custom-image:latest
   

3. Use the docker push command to push the image to the registry:

   Bash

   docker push <registry-name>.azurecr.io/appsvc-tutorial-custom-image:latest
   

   Uploading the image the first time might take a few minutes because it includes the base image. Subsequent uploads are typically faster.

   While you're waiting, you can complete the steps in the next section to configure App Service to deploy from the registry.

IV. Authorize the managed identity for your registry

The managed identity you created doesn't have authorization to pull from the container registry yet. In this step, you enable the authorization.

Azure CLI

1. Retrieve the principal ID for the managed identity:

   Azure CLI

   principalId=$(az identity show --resource-group msdocs-custom-container-tutorial --name myID --query principalId --output tsv)
   

2. Retrieve the resource ID for the container registry:

   Azure CLI

   registryId=$(az acr show --resource-group msdocs-custom-container-tutorial --name <registry-name> --query id --output tsv)
   

3. Grant the managed identity permission to access the container registry:

   Azure CLI

   az role assignment create --assignee $principalId --scope $registryId --role "AcrPull"
   

   For more information about these permissions, see What is Azure role-based access control?.

Azure portal

IV.A. Back in the management page for the container registry:

1. In the left navigation menu, select Access control (IAM).
2. Select Add role assignment.

IV.B. Select AcrPull in the list of roles.

IV.C.

1. Select the Members tab.
2. Under Assign access to, select Managed identity.
3. Under Members, select Select members.

IV.D.

1. In Managed identity, select User-assigned managed identity.
2. Under Select, select myID.

IV.E.

1. Select the Review + assign tab.
2. Select Review + assign at the bottom.

V. Create the web app

Azure CLI

1. Create an App Service plan using the az appservice plan create command:

   Azure CLI

   az appservice plan create --name myAppServicePlan --resource-group msdocs-custom-container-tutorial --is-linux
   

   An App Service plan corresponds to the virtual machine that hosts the web app. By default, the previous command uses an inexpensive B1 pricing tier that's free for the first month. You can specify the tier by using the --sku parameter.

2. Create the web app with the az webapp create command:

   Azure CLI

   az webapp create --resource-group msdocs-custom-container-tutorial --plan myAppServicePlan --name <app-name> --deployment-container-image-name <registry-name>.azurecr.io/appsvc-tutorial-custom-image:latest
   

   Replace <app-name> with a name for the web app. The name must be unique across all of Azure. Also replace <registry-name> with the name of your registry from the previous section.

   Näpunäide

   You can retrieve the web app's container settings at any time with the command az webapp config container show --name <app-name> --resource-group msdocs-custom-container-tutorial. The image is specified in the property DOCKER_CUSTOM_IMAGE_NAME. When the web app is deployed through Azure DevOps or Azure Resource Manager templates, the image can also appear in a property named LinuxFxVersion. Both properties serve the same purpose. If both are present in the web app's configuration, LinuxFxVersion takes precedence.

Azure portal

V.A. In the Azure portal:

1. Type "app" in the search bar at the top of the Azure portal.
2. Select the item labeled App Services under the Services heading.
3. Select Create. You can also navigate to the creation wizard directly.

V.B. In the create wizard:

1. In Subscription, select the subscription you used earlier.
2. In Resource group, select msdocs-custom-container-tutorial.
3. In Name, type a unique app name, which will be used in your app's default hostname <app-name>.azurewebsites.net.
4. In Publish, select Docker Container.
5. In Operating System, select Linux.
6. In Region, select West Europe, or a region near you.
7. In Linux Plan (West Europe), select Create new, type a plan name, and select OK.
8. In Pricing plan, select Change size.

V.C. In the Spec Picker:

1. Select Dev / Test.
2. Select B1.
3. Select Apply.

V.D. Back in the app creation wizard:

1. Select the Docker tab.
2. In Image Source, select Azure Container Registry.
3. In Registry, select the container registry you created earlier.
4. In Image, select appsvc-tutorial-custom-image.
5. In Tag, select latest.

V.E.

1. Select the Review + create tab.
2. Select Create.

V.F. When the creation of the web app is complete, you can open its management page by selecting Go to resource.

VI. Configure the web app

In this step, you configure the web app as follows:

• Configure the app to send requests to port 8000. The sample container is listening on port 8000 for web requests.
• Tell your app to use the managed identity to pull images from your container registry.
• Configure continuous deployment from the container registry (every image push to the registry will trigger your app to pull the new image). This part isn't needed for your web app to pull from your container registry, but it can let your web app know when a new image is pushed to the registry. Without it, you must manually trigger an image pull by restarting the web app.

Azure CLI

1. Use az webapp config appsettings set to set the WEBSITES_PORT environment variable as expected by the app code:

   Azure CLI

   az webapp config appsettings set --resource-group msdocs-custom-container-tutorial --name <app-name> --settings WEBSITES_PORT=8000
   

   Replace <app-name> with the name you used in the previous step.

2. Enable the user-assigned managed identity in the web app with the az webapp identity assign command:

   Azure CLI

   id=$(az identity show --resource-group msdocs-custom-container-tutorial --name myID --query id --output tsv)
   az webapp identity assign --resource-group msdocs-custom-container-tutorial --name <app-name> --identities $id
   

   Replace <app-name> with the name you used in the previous step.

3. Configure your app to pull from Azure Container Registry by using managed identities.

   Azure CLI

   appConfig=$(az webapp config show --resource-group msdocs-custom-container-tutorial --name <app-name> --query id --output tsv)
   az resource update --ids $appConfig --set properties.acrUseManagedIdentityCreds=True
   

   Replace <app-name> with the name you used in the previous step.

4. Set the client ID your web app uses to pull from Azure Container Registry. This step isn't needed if you use the system-assigned managed identity.

   Azure CLI

   clientId=$(az identity show --resource-group msdocs-custom-container-tutorial --name myID --query clientId --output tsv)
   az resource update --ids $appConfig --set properties.AcrUserManagedIdentityID=$clientId
   

5. Enable CI/CD in App Service.

   Azure CLI

   cicdUrl=$(az webapp deployment container config --enable-cd true --name <app-name> --resource-group msdocs-custom-container-tutorial --query CI_CD_URL --output tsv)
   

   CI_CD_URL is a URL that App Service generates for you. Your registry should use this URL to notify App Service that an image push occurred. It doesn't actually create the webhook for you.

6. Create a webhook in your container registry using the CI_CD_URL you got from the last step.

   Azure CLI

   az acr webhook create --name appserviceCD --registry <registry-name> --uri $cicdUrl --actions push --scope appsvc-tutorial-custom-image:latest
   

7. To test if your webhook is configured properly, ping the webhook and see if you get a 200 OK response.

   Azure CLI

   eventId=$(az acr webhook ping --name appserviceCD --registry <registry-name> --query id --output tsv)
   az acr webhook list-events --name appserviceCD --registry <registry-name> --query "[?id=='$eventId'].eventResponseMessage"
   

   Näpunäide

   To see all information about all webhook events, remove the --query parameter.

   If you're streaming the container log, you should see a Starting container for site message after the webhook ping because the webhook triggers the app to restart.

Azure portal

VI.A. On your web app's management page, select Configuration.

VI.B. On the Configuration page:

1. Select New application setting.
2. In Name, type WEBSITES_PORT.
3. In Value, type 8000.
4. Select OK.
5. Select Save in the top menu, then select Continue. The WEBSITES_PORT setting specifies the container port to forward web requests to. For more information, see custom container app settings.

VI.C. In the left navigation menu, select Identity. Then do the following on the Identity page:

1. Select the User assigned tab.
2. Select Add.

VI.D.

1. Select myID.
2. Select Add.

VI.E. In the left navigation menu, select Deployment Center. Then do the following on the Deployment Center page:

1. In Authentication, select Managed Identity.
2. In Identity, select myID.
3. In Continuous deployment, select On.
4. Select Save in the top menu. When you turn on continuous deployment to a container registry, a webhook is automatically added to the registry for your web app.

VI.F. On the Deployment Center page, select the Logs tab. Here, you can see log messages for pulling the image and starting the container. Later, you'll learn how to see generated console messages from within the container.

VII. Browse to the web app

Azure CLI

To test the app, browse to https://<app-name>.azurewebsites.net. Replace <app-name> with the name of your web app.

Azure portal

VII.A. On the App Service page:

1. In the left navigation menu, select Overview.
2. In URL, select the link.

The first time you attempt to access the app, it might take some time for the app to respond because App Service must pull the entire image from the registry. If the browser times out, just refresh the page. Once the initial image is pulled, subsequent tests will run much faster.

VIII. Access diagnostic logs

Azure CLI

While you're waiting for the App Service to pull in the image, it's helpful to see exactly what App Service is doing by streaming the container logs to your terminal.

1. Turn on container logging:

   Azure CLI

   az webapp log config --name <app-name> --resource-group msdocs-custom-container-tutorial --docker-container-logging filesystem
   

2. Enable the log stream:

   Azure CLI

   az webapp log tail --name <app-name> --resource-group msdocs-custom-container-tutorial
   

   If you don't see console logs immediately, check again in 30 seconds.

   You can also inspect the log files from the browser at https://<app-name>.scm.azurewebsites.net/api/logs/docker.

3. To stop log streaming at any time, select Ctrl+C.

Azure portal

On the Deployment Center page, you can already see the log messages for pulling and starting the container. In this step, you enable logging of the console output from within the container.

VIII.A. On the App Service page:

1. In the left navigation menu, select App Service logs.
2. In Application logging, select File System.
3. Select Save.

VIII.B. In the left navigation menu, select Log stream. You should now start to see the container's console output in the log stream.

IX. Modify the app code and redeploy

In this section, you make a change to the web app code, rebuild the image, and then push it to your container registry. App Service then automatically pulls the updated image from the registry to update the running web app.

1. In your local docker-django-webapp-linux folder, open the file app/templates/app/index.html.

2. Change the first HTML element to match the following code.

   HTML

   <nav class="navbar navbar-inverse navbar-fixed-top">
     <div class="container">
       <div class="navbar-header">
         <a class="navbar-brand" href="#">Azure App Service - Updated Here!</a>
       </div>
     </div>
   </nav>
   

3. Save your changes.

4. Change to the docker-django-webapp-linux folder and rebuild the image:

   Bash

   docker build --tag appsvc-tutorial-custom-image .
   

5. Update the image's tag to latest:

   Bash

   docker tag appsvc-tutorial-custom-image <registry-name>.azurecr.io/appsvc-tutorial-custom-image:latest
   

   Replace <registry-name> with the name of your registry.

6. Push the image to the registry:

   Bash

   docker push <registry-name>.azurecr.io/appsvc-tutorial-custom-image:latest
   

7. When the image push is complete, the webhook notifies App Service about the push, and App Service tries to pull in the updated image. Wait a few minutes, and then verify that the update has been deployed by browsing to https://<app-name>.azurewebsites.net.

X. Connect to the container using SSH

SSH enables improved-security communication between a container and a client. To enable an SSH connection to your container, you must configure your custom image for it. When the container is running, you can open an SSH connection.

Configure the container for SSH

The sample app used in this tutorial already has the necessary configuration in the Dockerfile, which installs the SSH server and also sets the sign-in credentials. This section is informational only. To connect to the container, skip to the next section.

Dockerfile

ENV SSH_PASSWD "root:Docker!"
RUN apt-get update \
        && apt-get install -y --no-install-recommends dialog \
        && apt-get update \
  && apt-get install -y --no-install-recommends openssh-server \
  && echo "$SSH_PASSWD" | chpasswd 

Märkus

This configuration doesn't allow external connections to the container. SSH is available only through the Kudu/SCM Site. The Kudu/SCM site is authenticated with your Azure account. root:Docker! should not be altered when you use SSH. SCM/KUDU will use your Azure portal credentials. Changing this value will result in an error when you use SSH.

The Dockerfile also copies the sshd_config file to the /etc/ssh/ folder and exposes port 2222 on the container:

Dockerfile

COPY sshd_config /etc/ssh/

# ...

EXPOSE 8000 2222

Port 2222 is an internal port accessible only by containers within the bridge network of a private virtual network.

Finally, the entry script, init.sh, starts the SSH server.

Bash

#!/bin/bash
service ssh start

Open the SSH connection to the container

Azure CLI

1. Browse to https://<app-name>.scm.azurewebsites.net/webssh/host and sign in with your Azure account. Replace <app-name> with the name of your web app.

2. When you sign in, you're redirected to an informational page for the web app. Select SSH at the top of the page to open the shell and use commands.

   For example, you can examine the processes running within the app by using the top command.

Azure portal

X.A. On the App Service page:

1. In the left navigation menu, select SSH.
2. Select Go.

X.B. The SSH session is opened in a new browser tab. Wait for the status bar at the bottom to show a green `SSH CONNECTION ESTABLISHED message. You can then run commands from within the container. Configuration changes made to your container aren't persisted across app restarts.

XI. Clean up resources

Azure CLI

The resources you created in this article might incur ongoing costs. To clean up the resources, you only need to delete the resource group that contains them:

Azure CLI

az group delete --name msdocs-custom-container-tutorial

Azure portal

XI.A. In the search bar at the top of the Azure portal:

1. Enter the resource group name.
2. Select the resource group.

XI.B. On the resource group page, select Delete resource group.

XI.C.

1. Enter the resource group name to confirm your deletion.
2. Select Delete.

Next steps

What you learned:

• Deploy a custom image to a private container registry.
• Deploy and the custom image in App Service.
• Update and redeploy the image.
• Access diagnostic logs.
• Connect to the container by using SSH.

• Push a custom Docker image to Azure Container Registry.
• Deploy the custom image to App Service.
• Configure environment variables.
• Pull the image into App Service by using a managed identity.
• Access diagnostic logs.
• Enable CI/CD from Azure Container Registry to App Service.
• Connect to the container by using SSH.

In the next tutorial, you learn how to provide security for your app with a custom domain and certificate.

 Provide security with custom domain and certificate

Or, check out other resources:

Configure a custom container

Tutorial: Configure a sidecar container for custom container in Azure App Service (preview)