How to run Java War file (Java Spring Boot) in App service plan as Windows Web App?

Question

How to run Java War file (Java Spring Boot) in App service plan as Windows Web App?

Wegscheider, Lukas 10

Hey,

previously I was running a Java WAR application in a linux web app on my App Service Plan but now I have to switch to a windows web app and I am facing some issues. With the linux web app I was able to define a startup command to launch my war file but it seems that windows webapp lack that functionality. Therefore I don't really know, how to manually/automatically start my application.

I deploy my infrastructure with Terraform and deploy my code with azure pipelines.

Thanks!

VenkateshDodda-MSFT 24,951 Reputation points Microsoft Employee Moderator

2023-03-23T09:10:31.32+00:00

@Wegscheider, Lukas Thank you for reaching out to Microsoft Q&A, apologize for any inconvenience caused on this.

As explained here Your .jar application must be named app.jar and keep it under site\wwwroot for App Service to identify and run your application. The platform will pick this up and deploy/run it for both Linux and Windows WebApps.

Alternatively, You can add a CLI Task in your devops pipeline to deploy the WAR/JAR/EAR packages by using the either az webapp deploy cmdlet pr through kudu publish api as mentioned here.

Feel free to reach back to me if you have any further questions on this.
Wegscheider, Lukas 10 Reputation points

2023-03-23T09:57:49.3266667+00:00

Hey, I am not working with jar files. I am using war files.
VenkateshDodda-MSFT 24,951 Reputation points Microsoft Employee Moderator

2023-03-23T10:10:00.49+00:00

@Wegscheider, Lukas Thanks for your response. As mentioned in my earlier response you can use the kudu publish api or through az deploy cmdlet you can deploy your .war file.
VenkateshDodda-MSFT 24,951 Reputation points Microsoft Employee Moderator

2023-03-28T04:02:36.83+00:00

@Wegscheider, Lukas Just following up to see if you have a chance to check my previous response and helped. Do let me know if you have any questions on this.
Wegscheider, Lukas 10 Reputation points

2023-03-28T11:34:59.3233333+00:00

I've tried everything now: Jar, War, Windows, Linux
I deployed it with a pipeline and with Visual Studio Extension. When using the Extension, Linux, Jar and appropriate Startup Command, I see correct application logs but still cannot access the website. Always getting 404
VenkateshDodda-MSFT 24,951 Reputation points Microsoft Employee Moderator

2023-03-28T12:11:26.3933333+00:00
@Wegscheider, Lukas Thanks for your response. As mentioned in your earlier response we have understood that your deployment is successful but when you are trying to request the root url you are landing with 404 error.
Could you please help us with more information on this to understand better

Have you run the webapp down detector under Diagnose and solve problems in your webapp from the portal to identify the issue.

What is the error message when you are trying to request the root URL of the website?

Share the webapp name and last four digits of your subscription id , issue start time (utc) to check and assist you further on this.

1 answer

Your answer

VenkateshDodda-MSFT 24,951 Reputation points Microsoft Employee Moderator

2023-03-23T09:10:31.32+00:00

@Wegscheider, Lukas Thank you for reaching out to Microsoft Q&A, apologize for any inconvenience caused on this.

As explained here Your .jar application must be named app.jar and keep it under site\wwwroot for App Service to identify and run your application. The platform will pick this up and deploy/run it for both Linux and Windows WebApps.

Alternatively, You can add a CLI Task in your devops pipeline to deploy the WAR/JAR/EAR packages by using the either az webapp deploy cmdlet pr through kudu publish api as mentioned here.

Feel free to reach back to me if you have any further questions on this.
Wegscheider, Lukas 10 Reputation points

2023-03-23T09:57:49.3266667+00:00

Hey, I am not working with jar files. I am using war files.
VenkateshDodda-MSFT 24,951 Reputation points Microsoft Employee Moderator

2023-03-23T10:10:00.49+00:00

@Wegscheider, Lukas Thanks for your response. As mentioned in my earlier response you can use the kudu publish api or through az deploy cmdlet you can deploy your .war file.
VenkateshDodda-MSFT 24,951 Reputation points Microsoft Employee Moderator

2023-03-28T04:02:36.83+00:00

@Wegscheider, Lukas Just following up to see if you have a chance to check my previous response and helped. Do let me know if you have any questions on this.
Wegscheider, Lukas 10 Reputation points

2023-03-28T11:34:59.3233333+00:00

I've tried everything now: Jar, War, Windows, Linux
I deployed it with a pipeline and with Visual Studio Extension. When using the Extension, Linux, Jar and appropriate Startup Command, I see correct application logs but still cannot access the website. Always getting 404
VenkateshDodda-MSFT 24,951 Reputation points Microsoft Employee Moderator

2023-03-28T12:11:26.3933333+00:00

@Wegscheider, Lukas Thanks for your response. As mentioned in your earlier response we have understood that your deployment is successful but when you are trying to request the root url you are landing with 404 error.
Could you please help us with more information on this to understand better

Have you run the webapp down detector under Diagnose and solve problems in your webapp from the portal to identify the issue.

What is the error message when you are trying to request the root URL of the website?

Share the webapp name and last four digits of your subscription id , issue start time (utc) to check and assist you further on this.

Answer 1

Switching from a Linux web app to a Windows web app on Azure App Service can cause some differences in the way you deploy and start your Java WAR application. In a Windows web app, you can set up the Java version and container (like Tomcat) using the App Settings.

Here's a general outline of the steps to deploy and start your Java WAR application on a Windows web app:

Create a Windows web app with your desired App Service Plan using Terraform (which you've likely already done).
Configure the Java version and container for the web app using App Settings.
Deploy the WAR file to the web app's wwwroot/webapps folder using Azure Pipelines.

For step 2, you can set the Java version and container using the Azure Portal or via Terraform. Here's an example of how to set up the required App Settings using Terraform:


resource "azurerm_app_service" "example" {
  # ... other configuration ...

  app_settings = {
    # Configure the Java version, e.g., Java 11
    "WEBSITE_CONFIG_ALLOWED_APP_EXTENSIONS" = ".jar,.war"
    "WEBSITE_CONFIG_USE_CUSTOM_JAVA"        = "true"
    "WEBSITE_CONFIG_JAVA_VERSION"           = "11"
    "WEBSITE_CONFIG_JAVA_OPTS"              = "-Djava.net.preferIPv4Stack=true"

    # Configure the container, e.g., Tomcat 9.0
    "WEBSITE_CONFIG_JAVA_CONTAINER"         = "Tomcat"
    "WEBSITE_CONFIG_JAVA_CONTAINER_VERSION" = "9.0"
  }
}

For step 3, to deploy the WAR file using Azure Pipelines, update your pipeline definition to include a task for deploying the WAR file to the web app's wwwroot/webapps folder. Here's an example YAML snippet for an Azure Pipelines task that deploys a WAR file to an Azure Web App:


- task: AzureRmWebAppDeployment@4
  inputs:
    ConnectionType: 'AzureRM'
    azureSubscription: 'Your-Azure-Subscription-Name'
    appType: 'webApp'
    WebAppName: 'Your-Web-App-Name'
    packageForLinux: '$(Build.ArtifactStagingDirectory)/**/*.war'
    VirtualApplication: 'wwwroot/webapps'

Replace Your-Azure-Subscription-Name and Your-Web-App-Name with the appropriate values for your Azure subscription and web app.

After deploying the WAR file to the wwwroot/webapps folder, the configured Java container (e.g., Tomcat) should automatically deploy and start the application. You can monitor the application's logs using the Azure Portal or other monitoring tools to ensure that the deployment and startup were successful.

Wegscheider, Lukas 10 Reputation points

2023-03-22T17:11:47.14+00:00

Everything seems to be fine, deployment is successful but when opening the URL, it‘s just displaying the „start-your-deployment-guide“ html. Anything else I have to consider?

I am pretty sure it‘s something quite obvious I‘m missing.
Sedat SALMAN 14,180 Reputation points MVP

2023-03-23T12:13:27.3133333+00:00

If you are seeing the "start-your-deployment-guide" HTML page instead of your deployed application when you navigate to your web app's URL, it could be due to one of the following reasons:

The WAR file is not being deployed to the correct directory: Make sure that you are deploying the WAR file to the correct directory. For a Tomcat container, the WAR file should be deployed to the "webapps" directory. For other containers, the directory may be different. Double-check that the WAR file is being deployed to the correct directory in your web app.

The context path is not configured correctly: If your application has a context path defined, you may need to configure it correctly in your web app's configuration. For example, if your application has a context path of "/myapp", you will need to make sure that your web app is configured to serve the application at the correct URL (e.g., https://mywebapp.azurewebsites.net/myapp).

The deployment is not being picked up by the web app: It's possible that the deployment is not being picked up by the web app for some reason. Try restarting your web app and monitoring the logs to see if the deployment is detected and the application is started.

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How to run Java War file (Java Spring Boot) in App service plan as Windows Web App?

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