Open-source technologies FAQs for Web Apps in Azure

This article has answers to frequently asked questions (FAQs) about issues with open-source technologies for the Web Apps feature of Azure App Service.

If your Azure issue is not addressed in this article, visit the Azure forums on MSDN and the Stack Overflow. You can post your issue in these forums, or post to @AzureSupport on Twitter. You also can submit an Azure support request. To submit a support request, on the Azure support page, select Get support.

My ClearDB database is down. How do I resolve this?

For database-related issues, contact ClearDB support.

For answers to common questions about ClearDB, see ClearDB FAQs.

Why isn't my ClearDB database listed in the portal?

If you create a ClearDB database in the Azure portal, the database doesn't appear in the Azure classic portal. To work around this, you can manually link your database to the web app.

Similarly, if you create a ClearDB database in the Azure classic portal, you won't see your database in the Azure portal. In this case, no workaround is available.

For more information, see FAQs for ClearDB MySQL databases with Azure App Service.

Why wasn't my ClearDB database migrated during my subscription migration?

When you perform resource migration across subscriptions, some limitations apply. A ClearDB MySQL database is a third-party service and is not migrated during an Azure subscription migration.

If you don't manage the migration of your MySQL database before you migrate your Azure resources, your ClearDB MySQL database might be unavailable. To avoid this, first, manually migrate your ClearDB database, and then migrate the Azure subscription for your web app.

For more information, see FAQs for ClearDB MySQL databases with Azure App Service.

How do I turn on PHP logging to troubleshoot PHP issues?

To turn on PHP logging:

  1. Sign in to your Kudu website.
  2. In the top menu, select Debug Console > CMD.
  3. Select the Site folder.
  4. Select the wwwroot folder.
  5. Select the + icon, and then select New File.
  6. Set the file name to .user.ini.
  7. Select the pencil icon next to .user.ini.
  8. In the file, add this code: log_errors=on
  9. Select Save.
  10. Select the pencil icon next to wp-config.php.
  11. Change the text to the following code: //Enable WP_DEBUG modedefine('WP_DEBUG', true);//Enable debug logging to /wp-content/debug.logdefine('WP_DEBUG_LOG', true); //Supress errors and warnings to screendefine('WP_DEBUG_DISPLAY', false);//Supress PHP errors to screenini_set('display_errors', 0);
  12. In the Azure portal, in the web app menu, restart your web app.

For more information, see Enable WordPress error logs.

How do I log Python application errors in apps that are hosted in App Service?

To capture Python application errors:

  1. In the Azure portal, in your web app, select Settings.
  2. On the Settings tab, select Application settings.
  3. Under App settings, enter the following key/value pair:
    • Key : WSGI_LOG
    • Value : D:\home\site\wwwroot\logs.txt (enter your choice of file name)

You should now see errors in the logs.txt file in the wwwroot folder.

How do I change the version of the Node.js application that is hosted in App Service?

To change the version of the Node.js application, you can use one of the following options:

  • In the Azure portal, use App settings.
    1. In the Azure portal, go to your web app.
    2. On the Settings blade, select Application settings.
    3. In App settings, you can include WEBSITE_NODE_DEFAULT_VERSION as the key, and the version of Node.js you want as the value.
    4. Go to your Kudu console.
    5. To check the Node.js version, enter the following command:
      node -v
  • Modify the iisnode.yml file. Changing the Node.js version in the iisnode.yml file only sets the runtime environment that iisnode uses. Your Kudu cmd and others still use the Node.js version that is set in App settings in the Azure portal.

    To set the iisnode.yml manually, create an iisnode.yml file in your app root folder. In the file, include the following line:

    nodeProcessCommandLine: "D:\Program Files (x86)\nodejs\5.9.1\node.exe"
    
  • Set the iisnode.yml file by using package.json during source control deployment. The Azure source control deployment process involves the following steps:

    1. Moves content to the Azure web app.
    2. Creates a default deployment script, if there isn’t one (deploy.cmd, .deployment files) in the web app root folder.
    3. Runs a deployment script in which it creates an iisnode.yml file if you mention the Node.js version in the package.json file > engine "engines": {"node": "5.9.1","npm": "3.7.3"}
    4. The iisnode.yml file has the following line of code: nodeProcessCommandLine: "D:\Program Files (x86)\nodejs\5.9.1\node.exe"

I see the message "Error establishing a database connection" in my WordPress app that's hosted in App Service. How do I troubleshoot this?

If you see this error in your Azure WordPress app, to enable php_errors.log and debug.log, complete the steps detailed in Enable WordPress error logs.

When the logs are enabled, reproduce the error, and then check the logs to see if you are running out of connections:

[09-Oct-2015 00:03:13 UTC] PHP Warning: mysqli_real_connect(): (HY000/1226): User ‘abcdefghijk79' has exceeded the ‘max_user_connections’ resource (current value: 4) in D:\home\site\wwwroot\wp-includes\wp-db.php on line 1454

If you see this error in your debug.log or php_errors.log files, your app is exceeding the number of connections. If you’re hosting on ClearDB, verify the number of connections that are available in your service plan.

How do I debug a Node.js app that's hosted in App Service?

  1. Go to your Kudu console.
  2. Go to your application logs folder (D:\home\LogFiles\Application).
  3. In the logging_errors.txt file, check for content.

How do I install native Python modules in an App Service web app or API app?

Some packages might not install by using pip in Azure. The package might not be available on the Python Package Index, or a compiler might be required (a compiler is not available on the computer that is running the web app in App Service). For information about installing native modules in App Service web apps and API apps, see Install Python modules in App Service.

How do I deploy a Django app to App Service by using Git and the new version of Python?

For information about installing Django, see Deploying a Django app to App Service.

Where are the Tomcat log files located?

For Azure Marketplace and custom deployments:

  • Folder location: D:\home\site\wwwroot\bin\apache-tomcat-8.0.33\logs
  • Files of interest:
    • catalina.yyyy-mm-dd.log
    • host-manager.yyyy-mm-dd.log
    • localhost.yyyy-mm-dd.log
    • manager.yyyy-mm-dd.log
    • site_access_log.yyyy-mm-dd.log

For portal App settings deployments:

  • Folder location: D:\home\LogFiles
  • Files of interest:
    • catalina.yyyy-mm-dd.log
    • host-manager.yyyy-mm-dd.log
    • localhost.yyyy-mm-dd.log
    • manager.yyyy-mm-dd.log
    • site_access_log.yyyy-mm-dd.log

How do I troubleshoot JDBC driver connection errors?

You might see the following message in your Tomcat logs:

The web application[ROOT] registered the JDBC driver [com.mysql.jdbc.Driver] but failed to unregister it when the web application was stopped. To prevent a memory leak,the JDBC Driver has been forcibly unregistered

To resolve the error:

  1. Remove the sqljdbc*.jar file from your app/lib folder.
  2. If you are using the custom Tomcat or Azure Marketplace Tomcat web server, copy this .jar file to the Tomcat lib folder.
  3. If you are enabling Java from the Azure portal (select Java 1.8 > Tomcat server), copy the sqljdbc.* jar file in the folder that's parallel to your app. Then, add the following classpath setting to the web.config file:

    <httpPlatform>
    <environmentVariables>
    <environmentVariablename ="JAVA_OPTS" value=" -Djava.net.preferIPv4Stack=true
    -Xms128M -classpath %CLASSPATH%;[Path to the sqljdbc*.jarfile]" />
    </environmentVariables>
    </httpPlatform>
    

Why do I see errors when I attempt to copy live log files?

If you try to copy live log files for a Java app (for example, Tomcat), you might see this FTP error:

Error transferring file [filename] Copying files from remote side failed.

The process cannot access the file because it is being used by another process.

The error message might vary, depending on the FTP client.

All Java apps have this locking issue. Only Kudu supports downloading this file while the app is running.

Stopping the app allows FTP access to these files.

Another workaround is to write a WebJob that runs on a schedule and copies these files to a different directory. For a sample project, see the CopyLogsJob project.

Where do I find the log files for Jetty?

For Marketplace and custom deployments, the log file is in the D:\home\site\wwwroot\bin\jetty-distribution-9.1.2.v20140210\logs folder. Note that the folder location depends on the version of Jetty you are using. For example, the path provided here is for Jetty 9.1.2. Look for jetty_YYYY_MM_DD.stderrout.log.

For portal App Setting deployments, the log file is in D:\home\LogFiles. Look for jetty_YYYY_MM_DD.stderrout.log

Can I send email from my Azure web app?

App Service doesn't have a built-in email feature. For some good alternatives for sending email from your app, see this Stack Overflow discussion.

Why does my WordPress site redirect to another URL?

If you have recently migrated to Azure, WordPress might redirect to the old domain URL. This is caused by a setting in the MySQL database.

WordPress Buddy+ is an Azure Site Extension that you can use to update the redirection URL directly in the database. For more information about using WordPress Buddy+, see WordPress tools and MySQL migration with WordPress Buddy+.

Alternatively, if you prefer to manually update the redirection URL by using SQL queries or PHPMyAdmin, see WordPress: Redirecting to wrong URL.

How do I change my WordPress sign-in password?

If you have forgotten your WordPress sign-in password, you can use WordPress Buddy+ to update it. To reset your password, install the WordPress Buddy+ Azure Site Extension, and then complete the steps described in WordPress tools and MySQL migration with WordPress Buddy+.

I can't sign in to WordPress. How do I resolve this?

If you find yourself locked out of WordPress after recently installing a plugin, you might have a faulty plugin. WordPress Buddy+ is an Azure Site Extension that can help you disable plugins in WordPress. For more information, see WordPress tools and MySQL migration with WordPress Buddy+.

How do I migrate my WordPress database?

You have multiple options for migrating the MySQL database that's connected to your WordPress website:

How do I help make WordPress more secure?

To learn about security best practices for WordPress, see Best practices for WordPress security in Azure.

I am trying to use PHPMyAdmin, and I see the message “Access denied.” How do I resolve this?

You might experience this issue if the MySQL in-app feature isn't running yet in this App Service instance. To resolve the issue, try to access your website. This starts the required processes, including the MySQL in-app process. To verify that MySQL in-app is running, in Process Explorer, ensure that mysqld.exe is listed in the processes.

After you ensure that MySQL in-app is running, try to use PHPMyAdmin.

I get an HTTP 403 error when I try to import or export my MySQL in-app database by using PHPMyadmin. How do I resolve this?

If you are using an older version of Chrome, you might be experiencing a known bug. To resolve the issue, upgrade to a newer version of Chrome. Also try using a different browser, like Internet Explorer or Edge, where the issue does not occur.