Tutorial / Cram Notes
Extensions can help with:
- Configuration Management: Apply configuration settings like PowerShell DSC (Desired State Configuration), or CHEF/Puppet.
- Security and Identity: Implement features such as anti-malware or use Managed Service Identity for accessing Azure services without storing credentials in code.
- Developer Tools: Enable debugging and diagnostic tools.
- Application Installation: Use extensions like the Custom Script Extension to install applications.
- File manipulation: Modify files on VMs during run time.
Commonly Used Azure VM Extensions
- Custom Script Extension: Executes scripts on Azure VMs.
- VM Access Extension: Resets administrative credentials, fixes RDP/SSH network issues, etc.
- DSC Extension: Implements PowerShell DSC configurations.
- BGInfo Extension: Deploys BGInfo tool for desktop background with system info.
- Antimalware Extension: Provides real-time protection against malware.
- Diagnostics Extension: Enables, configures, and consumes diagnostics data.
Deploying VM Extensions
Using Azure Portal
To deploy VM extensions through the Azure Portal:
- Navigate to the Azure Portal and select the desired VM.
- Under Settings, find ‘Extensions’ and select ‘Add’.
- Choose the specific extension that you want to deploy.
- Configure the extension with the required settings, like script paths or version.
- Click ‘Create/OK’ to deploy the extension.
Using Azure PowerShell
For PowerShell, the cmdlet Set-AzVMExtension is used:
Set-AzVMExtension -ResourceGroupName “ResourceGroup” -VMName “VMName” -Name “ExtensionName” -Publisher “PublisherName” -ExtensionType “ExtensionType” -TypeHandlerVersion “Version” -Settings $SettingsObject
Using Azure CLI
For Azure CLI, the command az vm extension set is applied:
az vm extension set –resource-group ResourceGroup –vm-name VMName –name ExtensionName –publisher PublisherName –settings SettingsFile –version Version
Examples
– Custom Script Extension using Azure CLI:
az vm extension set \
–resource-group MyResourceGroup \
–vm-name MyVM \
–name CustomScript \
–publisher Microsoft.Azure.Extensions \
–settings ‘{ “fileUris”: [“http://example.com/script.sh”], “commandToExecute”: “./script.sh” }’
– DSC Extension with Azure PowerShell:
$ConfigurationArgument = @{
“nodeName” = “localhost”;
“MOFURL” = “<URL to the .mof file>”;
“ConfigurationData” = “<URL to the .pdt file>”;
}
Set-AzVmDscExtension -ResourceGroupName “MyResourceGroup” -VMName “MyVM” -ArchiveBlobName “MyDscConfiguration.zip” -AutoUpdate:$true -ConfigurationDataUri $ConfigurationArgument[“ConfigurationData”] -ConfigurationName “MyConfig” -ModuleVersion “2.76” -Name “Dsc” -Version “2.9”
Best Practices for VM Extensions
- Idempotency: Ensure that the extension’s action is idempotent, meaning that it can run multiple times without causing unintended effects.
- Secure Configuration Data: Protect sensitive data when passing to extensions (e.g., use Azure Key Vault for secrets).
- Monitoring: Utilize Azure Monitor to track the status and health of your extensions.
- Testing: Test extensions in a non-production environment before rolling out to production.
Troubleshooting VM Extensions
- View extension execution output: Check extension status and logs, typically found in the directory
/var/log/azure/(Linux) orC:\WindowsAzure\Logs(Windows). - Review extension statuses: In the Portal under VM settings, in PowerShell with
Get-AzVMExtension, or in CLI withaz vm extension list. - Remove extensions: In case of failure or conflicts, remove extensions via Azure portal or the CLI/PowerShell.
Conclusion
VM extensions provide a powerful way to manage, configure, and troubleshoot Azure VMs post-deployment. As an Azure Administrator, knowing how to deploy, manage, and diagnose these extensions forms an important part of the skill set needed for the AZ-104 certification. Remember to adhere to best practices and security measures when working with VM extensions to ensure your Azure environment’s optimal performance and security.
Practice Test with Explanation
True/False: VM extensions can only be installed at the time of VM creation.
- True
- False
Answer: False
Explanation: VM extensions can be added both during VM creation and after the VM has been provisioned.
Single Select: Which Azure service is primarily used for managing VM extensions?
- Azure Functions
- Azure Automation
- Azure Resource Manager
- Azure Service Fabric
Answer: Azure Resource Manager
Explanation: Azure Resource Manager is used to deploy and manage VM extensions as part of Azure resource templates.
True/False: You must always restart your VM in order to complete the installation of a new VM extension.
- True
- False
Answer: False
Explanation: While some extensions may require a restart, it is not always necessary to restart a VM to complete the installation of an extension.
Multiple Select: Which of the following items can be configured using VM extensions? (Select all that apply)
- Antivirus installation
- Custom Script Execution
- VM Size scaling
- Network configuration
- File backups
Answer: Antivirus installation, Custom Script Execution, File backups
Explanation: VM extensions can be used to configure antivirus installation, execute custom scripts, and process file backups. VM size scaling is done through VM size properties, and network configuration is managed separately.
True/False: Azure VM extensions can be deployed using Azure CLI.
- True
- False
Answer: True
Explanation: Azure VM extensions can be deployed using Azure CLI, PowerShell, ARM templates, and through the Azure portal.
Single Select: What is the purpose of the Azure Custom Script Extension?
- To monitor VM performance
- To automate software installations
- To execute scripts to configure VMs
- To resize VM disks
Answer: To execute scripts to configure VMs
Explanation: Azure Custom Script Extension is used to automatically execute scripts on Azure VMs to configure the VM after deployment.
True/False: VM extensions can be used to make configuration changes to the OS and the applications on an Azure VM.
- True
- False
Answer: True
Explanation: VM extensions are designed to enable post-deployment configuration and automation tasks inside Azure VMs.
Single Select: Which of the following VM extensions can be used for configuration management?
- Microsoft Antimalware
- Azure Backup
- SQL Server IaaS Extension
- Desired State Configuration (DSC)
Answer: Desired State Configuration (DSC)
Explanation: Desired State Configuration (DSC) is an extension that facilitates configuration management for VMs running on Azure.
True/False: VM extensions are platform-independent and can be used on any operating system.
- True
- False
Answer: False
Explanation: Some VM extensions are specific to Windows or Linux and cannot be used interchangeably.
Multiple Select: Which PowerShell cmdlet can be used to add or update a VM extension? (Select all that apply)
- Add-AzVMExtension
- Update-AzVMExtension
- Set-AzVMExtension
- Get-AzVMExtension
Answer: Add-AzVMExtension, Set-AzVMExtension
Explanation: ‘Add-AzVMExtension’ is used to add a new extension to a VM, and ‘Set-AzVMExtension’ is used to update an existing extension or add a new one if it does not exist. ‘Get-AzVMExtension’ is used to retrieve extension details, and there’s no ‘Update-AzVMExtension’ cmdlet.
True/False: You can use VM extensions to install specific versions of software packages on Azure VMs.
- True
- False
Answer: True
Explanation: Some VM extensions support installing specific versions of software packages on Azure VMs, offering granular control over the software deployment.
Single Select: Azure VM extensions are managed and updated through which kind of model?
- Infrastructure-as-a-Service (IaaS)
- Extension-as-a-Service (EaaS)
- Platform-as-a-Service (PaaS)
- Software-as-a-Service (SaaS)
Answer: Infrastructure-as-a-Service (IaaS)
Explanation: Azure VM extensions are part of the Infrastructure-as-a-Service (IaaS) offering, as they directly interact with the virtual machine infrastructure.
Interview Questions
What are VM extensions in Azure?
VM extensions in Azure are software packages that can be installed on Azure VMs to add additional functionality.
What can VM extensions be used for?
VM extensions can be used to install and configure software, perform maintenance tasks, and enable advanced monitoring and diagnostics.
What is the Custom Script extension?
The Custom Script extension is a powerful tool that allows you to execute custom scripts on your Azure VMs.
How do I deploy the Custom Script extension on a Windows VM?
To deploy the Custom Script extension on a Windows VM, open the Azure Portal, navigate to your VM, and click on the “Extensions” option in the left-hand menu. Then, click on the “Add” button and select the “Custom Script Extension” option from the list of available extensions.
How do I deploy the Custom Script extension on a Linux VM?
To deploy the Custom Script extension on a Linux VM, open the Azure Portal, navigate to your Linux VM, and click on the “Extensions” option in the left-hand menu. Then, click on the “Add” button and select the “Custom Script Extension” option from the list of available extensions.
What kind of scripts can I execute with the Custom Script extension?
You can execute any type of script with the Custom Script extension, including PowerShell, Bash, and Python scripts.
Can I pass command-line arguments to my script when using the Custom Script extension?
Yes, you can pass command-line arguments to your script when using the Custom Script extension.
How do I specify the script file to execute with the Custom Script extension?
You specify the script file to execute with the Custom Script extension by providing the file path in the extension configuration.
Can I execute multiple scripts with the Custom Script extension?
Yes, you can execute multiple scripts with the Custom Script extension by specifying the file paths and command-line arguments for each script.
How do I check the status of the Custom Script extension after deploying it?
You can check the status of the Custom Script extension by navigating to the “Extensions” page for your VM and reviewing the status of the extension.
Can I automate the deployment of the Custom Script extension?
Yes, you can automate the deployment of the Custom Script extension by using Azure Resource Manager templates or the Azure CLI.
What other types of extensions are available for Azure VMs?
Other types of extensions available for Azure VMs include monitoring extensions, security extensions, and diagnostic extensions.
Can I develop my own custom VM extension?
Yes, you can develop your own custom VM extension using Azure PowerShell or the Azure CLI.
Can I update or remove a VM extension after it has been deployed?
Yes, you can update or remove a VM extension after it has been deployed by navigating to the “Extensions” page for your VM and making the necessary changes.
How do I troubleshoot issues with a VM extension?
You can troubleshoot issues with a VM extension by reviewing the extension logs, which are available in the Azure Portal or by using Azure PowerShell or the Azure CLI.
I am preparing for the AZ-104 exam and struggling with understanding how to deploy virtual machine extensions. Can anyone provide some insights?
I have successfully deployed virtual machine extensions using ARM templates. It was a smooth process for me.
What are some common virtual machine extensions that are used in Azure deployments?
I faced some challenges while configuring the VM Access Extension. Has anyone else experienced the same?
Azure VM extensions offer additional capabilities beyond the base VM configuration. It’s important to understand how to leverage them for your specific requirements.
I find the Azure CLI to be more efficient for deploying VM extensions compared to other methods. Anyone else prefer using the CLI?
Can someone share their experience with troubleshooting VM extensions in Azure? I encountered an error message that I couldn’t resolve.
I appreciate the detailed explanation on how to deploy VM extensions. This information will definitely help me in my exam preparation.