Use Pester to Test Azure Resource Manager Templates for Best Practices

Recently I came across the amazing Secure DevOps Kit for Azure (AzSK). This contains a really useful AzSK PowerShell Module that contains cmdlets for performing different types of security scanning on Azure Resources, Subscriptions and Resource Manager Templates.

The feature of this module that I was most interested in for my current project was being able to scan ARM templates for best practice violations. The module contains several

To install the module, open a PowerShell Window and run:

Important: At the time of writing this post, the AzSK module has dependencies on the AzureRM.Profile and other AzureRM.* PowerShell modules. As of December 2018, the AzureRM.* PowerShell Modules are going to be renamed to Az.* (see this post). The AzureRM and Az modules can not be installed side-by-side, so if you’ve installed the Az PowerShell modules on your system then the installation of AzSK will fail because the AzureRM modules will also be installed and a conflict will occur.

The cmdlet we’re most interested in is the Get-AzSKARMTemplateSecurityStatus. It can be used to scan one or more ARM templates or entire folders of ARM templates for best practice violations:

This will scan the ARM templates and produce a CSV report in a folder Microsoft\AzSKLogs\ARMChecker within your $ENV:LOCALAPPDATA folder and open the folder in Explorer. This isn’t ideal for automation scenarios or using during Continuous Integration or Continuous Delivery pipelines. I’ve raised an issue with the AzSK team on GitHub to see if this can be improved.

In my case, I wanted to be able to use the PowerShell Pester Module, a PowerShell testing framework, to execute tests on the output and then use the nUnit output Pester generates to publish into a Continuous Integration pipeline. To do that I needed to create a custom test script that would take the CSV report, count the failures of each level (High, Medium or Low) and fail if any are counted in the specific level.

This is what the script looks like:

You can download the script from GitHub Gist directly or get it from the PowerShell Gallery by running:

Install-Script -Name AzSKARMTemplateSecurityStatus.Test

To use it you will need to install Pester 4.3.0 and AzSK 3.6.1 modules:

Once that is done, you can use Invoke-Pester and pass in the TemplatePath and Severity parameters to the test script:

This will execute the Pester tests in the file above on the specified ARM template. The tests will fail when there are any best practice violations with the specified Severity or above. If you didn’t pass in a Severity then it will default to failing on Medium and High.

If you use the OutputFile and OutputFormat parameters to cause Pester to output an NUnit format file that most Continuous Integration tools will happily accept and use to display the output of the tests.

If you installed the script from the PowerShell Gallery, you can also run the tests like this:

AzSKARMTemplateSecurityStatus.Test -TemplatePath D:\101-webapp-basic-windows\azuredeploy.json

Finally, if you’re using Azure DevOps, you can also get this function as part Secure DevOps Kit (AzSK) CICD Extensions for Azure in the Azure DevOps Marketplace.

Which ever way you choose to consume AzSK, it is a great module and well worth including in your CI/CD pipelines to ensure your ARM templates meet best practices.

 

 

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Managing Users & Permissions in Cosmos DB with PowerShell

If you’re just getting started with Cosmos DB, you might not have come across users and permissions in a Cosmos DB database. However, there are certain use cases where managing users and permissions are necessary. For example, if you’re wanting to be able to limit access to a particular resource (e.g. a collection, document, stored procedure) by user.

The most common usage scenario for users and permissions is if you’re implementing a Resource Token Broker type pattern, allowing client applications to directly access the Cosmos DB database.

Side note: The Cosmos DB implementation of users and permissions only provides authorization – it does not provide authentication. It would be up to your own implementation to manage the authentication. In most cases you’d use something like Azure Active Directory to provide an authentication layer.

But if you go hunting through the Azure Management Portal Cosmos DB data explorer (or Azure Storage Explorer) you won’t find any way to configure or even view users and permissions.

To manage users and permissions you need to use the Cosmos DB API directly or one of the SDKs.

But to make Cosmos DB users and permissions easier to manage from PowerShell, I created the Cosmos DB PowerShell module. This is an open source project hosted on GitHub. The Cosmos DB module allows you to manage much more than just users and permissions, but for this post I just wanted to start with these.

Requirements

This module works on PowerShell 5.x and PowerShell Core 6.0.0. It probably works on PowerShell 3 and 4, but I don’t have any more machines running this version to test on.

The Cosmos DB module does not have any dependencies, except if you call the New-Cosmos DbContext function with the ResourceGroup parameter specified as this will use the AzureRM PowerShell modules to read the Master Key for the connection directly from your Cosmos DB account. So I’d recommend installing the Azure PowerShell modules or if you’re using PowerShell 6.0, install the AzureRM.NetCore modules.

Installing the Module

The best way to install the Cosmos DB PowerShell module is from the PowerShell Gallery. To install it for only your user account execute this PowerShell command:

Install-Module -Name CosmosDB -Scope CurrentUser

Or to install it for all users on the machine (requires administrator permissions):

Install-Module -Name CosmosDB

Context Variable

Update 2018-03-06

As of Cosmos DB module v2.0.1, the connection parameter has been renamed to context and the New-CosmosDbConnection function has been renamed New-CosmosDbContext. This was to be more inline with naming adopted by the Azure PowerShell project. The old connection parameters and New-CosmosDbConnection function is still available as an alias, so older scripts won’t break. But these should be changed to use the new naming if possible as I plan to deprecate the connection version at some point in the future.

This post was updated to specify the new naming, but screenshots still show the Connection aliases.

Before you get down to the process of working with Cosmos DB resources, you’ll need to create a context variable containing the information required to connect. This requires the following information:

1. The Cosmos DB Account name
2. The Cosmos DB Database name
3. The Master Key for the account (you can have the Cosmos DB PowerShell module get this directly from your Azure account if you wish).

To create the connection variable we just use the New-CosmosDbContext:

If you do not wish to specify your master key, you can have the New-CosmosDbContext function pull your master key from the Azure Management Portal directly:

Note: This requires the AzureRM.Profile and AzureRM.Resoures module on Windows PowerShell 5.x or AzureRM.Profile.NetCore and AzureRM.Resources.NetCore on PoweShell Core 6.0.0.

Managing Users

To add a user to the Cosmos DB Database use the New-CosmosDBUser function:

New-CosmosDbUser -Context $context -Id 'daniel'

To get a list of users in the database:

Get-CosmosDbUser -Context $context

To get a specific user:

Get-CosmosDbUser -Context $context -Id 'daniel'

To remove a user (this will also remove all permissions assigned to the user):

Remove-CosmosDbUser -Context $context -Id 'daniel'

Managing Permissions

Permissions in Cosmos DB are granted to a user for a specific resource. For example, you could grant a user access to just a single document, an entire collection or to a stored procedure.

To grant a permission you need to provide four pieces of information:

1. The Id of the user to grant the permission to.
2. An Id for the permission to create. This is just string to uniquely identify the permission.
3. The permission mode to the permission: All or Read.
4. The Id of the resource to grant access to. This can be generated from one of the Get-CosmosDb*ResourcePath functions in the CosmosDB PowerShell module.

In the following example, we’ll grant the user daniel all access to the TestCollection:

Once a permission has been granted, you can use the Get-CosmosDbPermission function to retrieve the permission and with it the Resource Token that can be used to access the resource for a limited amount of time (between 10 minutes and 5 hours).

Note: as you have the Master Key already, using the Resource Token isn’t required.

For example, to retrieve all permissions for the user with Id daniel and a resource token expiration of 600 seconds:

Get-CosmosDbPermission -Context $context -UserId 'daniel' -TokenExpiry '600' |
fl *

You can as expected delete a permission by using the Remove-CosmosDbPermission function:

Remove-CosmosDbPermission -Context $context -UserId 'daniel' -Id 'AccessTestCollection'

Final Thoughts

So this is pretty much all there is to managing users and permissions using the Cosmos DB PowerShell module. This module can also be used to manage the following Cosmos DB resources:

• Attachments
• Collections
• Databases
• Documents
• Offers
• Stored procedures
• Triggers
• User Defined Functions

You can find additional documentation and examples of how to manage these resources over in the Cosmos DB PowerShell module readme file on GitHub.

Hopefully this will help you in any Cosmos DB automation tasks you might need to implement.

 

Configure Azure SQL Server Automatic Tuning with PowerShell

One thing I’ve found with configuring Azure services using automation (e.g. Azure PowerShell Modules, Azure Resource Manager template) is that the automation features are a little bit behind the feature set. For example, the Azure PowerShell modules may not yet implement settings for new or preview features. This can be a an issue if you’re strictly deploying everything via code (e.g. infrastructure as code). But if you run into a problem like this, all is not lost. So read on for an example of how to solve this issue.

Azure REST APIs

One of the great things about Azure is that everything is configurable by making direct requests to the Azure REST APIs, even if it is not available in ARM templates or Azure PowerShell.

Depending on the feature/configuration you can sometimes use the Set-AzureRmResource cmdlets to make calls to the REST APIs. But this cmdlet is limited to using an HTTP method of POST. So if you need to use PATCH, you’ll need to find an alternate way to make the call.

So, what you need then is to use the Invoke-RestMethod cmdlet to create a custom call to the REST API. This is the process I needed to use to configure the Azure SQL Server Automatic Tuning settings and what I’ll show in my script below.

The Script

The following script can be executed in PowerShell (of course) and requires a number of parameters to be passed to it:

• SubscriptionId – the subscription Id of the Azure subscription that contains the Azure SQL Server.
• ResourceGroupName – The name of the resource group containing SQL Server or
  database.
• ServerName – The name of the Azure SQL Server to set the automatic tuning
  options on.
• DatabaseName – The name of the Azure SQL Database to set the automatic tuning options on. If you pass this parameter then the automatic tuning settings are applied to the Azure SQL Database, not the server.
• Mode – This defines where the settings for the automatic tuning are
  obtained from. Inherit is only valid if the DatabaseName is specified.
• CreateIndex – Enable automatic tuning for creating an index.
• DropIndex – Enable automatic tuning for dropping an index.
• ForceLastGoodPlan – Enable automatic tuning for forcing last good plan.

Requirements: You need to have the installed the AzureRM.Profile PowerShell module (part of the AzureRM PowerShell Modules) to use this script. The script also requires you to have logged into your Azure Subscription using Add-AzureRmAccount (as a user or Service Principal).

Example Usage

To apply custom automatic tuning to an Azure SQL Server:

.\Set-AzureRMSqlServerAutotuning.ps1 -SubscriptionId '<Subscription Id>' -ResourceGroupName '<Resource Group name>' -ServerName '<Azure SQL server name>' -Mode Custom -CreateIndex On -DropIndex On -ForceLastGoodPlan Off

To apply custom automatic tuning to an Azure SQL Database:

.\Set-AzureRMSqlServerAutotuning.ps1 -SubscriptionId '<Subscription Id>' -ResourceGroupName '<Resource Group name>' -ServerName '<Azure SQL server name>' -DatabaseName '<Azure SQL database name>' -Mode Custom -CreateIndex On -DropIndex On -ForceLastGoodPlan Off

Conclusion

I’ve not yet encountered something in Azure that I can’t configure via the Azure REST APIs. This is because the Azure Management Portal uses the same APIs – so if it is available in the portal then you can do it via the Azure REST APIs. The biggest challenge is determining the body, header and methods available if the APIs are not yet documented.

If the API you need is not documented then you can raise a question in the Microsoft Azure Forums or on Stack Overflow. Failing that you can use the developer tools in your browser of choice to watch the API calls being made to the portal – I’ve had to resort to this many times, but documenting that process is something I’ll save for another day.

 

Stop, Start or Restart all Web Apps in Azure using PowerShell

Here is a short (and sometimes handy) single line of PowerShell code that can be used to restart all the Azure Web Apps in a subscription:

Note: Use this with care if you’re working with production systems because this _will_ restart these Web Apps without confirming first.

This would be a handy snippet to be able to run in the Azure Cloud Shell. It could also be adjusted to perform different actions on other types of resources.

To stop all Web Apps in a subscription use:

To start them all again:

The key part of this command is the GetEnumerator() method because most Azure Cmdlets don’t return an array of individual objects into the pipeline like typical PowerShell cmdlets. Instead returning a System.Collections.Generic.List object, which requires a slight adjustment to the code. This procedure can be used for most Azure Cmdlets to allow the results to be iterated through.

Thanks for reading.

Install Nightly Build of Azure CLI 2.0 on Windows

The Azure PowerShell cmdlets are really first class if you’re wanting to manage Azure with PowerShell. However, they don’t always support the very latest Azure components and features. For example, at the time of writing this there is no Azure PowerShell module for managing Azure Container Instances.

The solution to this is to install the Nightly Build of Azure CLI 2.0. However, on Windows it is not entirely clear the easiest way to do this. So, in this post I’ll provide a PowerShell script that will:

1. Install Python 3.x using Chocolatey
2. Use PIP (Python package manager) to install the latest nightly build packages
3. Update the Environment Path variable so that you can use Azure CLI 2.0.

Note: If you have the stable build of Azure CLI 2.0 installed using the MSI then you’ll need to configure your Environment Path variable to find the Az command that you’d like to use by default. I personally removed the stable build of Azure CLI 2.0 to make it easier.

Performing the Install

Make sure you’ve got Chocolatey installed. If you aren’t sure what Chocolatey is, it is a package management system for Windows – not unlike Apt-Get or Yum for Linux. It is free and awesome. In this process we’ll use Chocolatey to install Python for us. If you haven’t got Chocolatey installed, see this page for instructions.

Next, download and run this PowerShell script in a PowerShell Administrator Console:

You could save the content of this script into a PS1 file and then execute it like this:

It will then download and install Python, then use PIP to install the current nightly build packages. After a few minutes the installation will complete:

You can then run:

Az Login

To get started.

If you’re a bit new to Azure CLI 2.0, then another great way is to use Azure CLI Interactive:

Az Interactive

If you need to update to a newer nightly build, just run the script again and it will update your packages.

Easy as that! Now you can experiment with all the latest automation features in Azure without needing to wait for a new version of Azure CLI 2.0 or for latest Azure PowerShell cmdlets.

Edge Builds

If you want to install even more “bleeding edge” builds (built straight off the master branch on every merge to master) then you can make a small adjustment to the script above:

On line 34 change the URL of the feed from:

https://azureclinightly.blob.core.windows.net/packages

To:

https://azurecliprod.blob.core.windows.net/edge

Thanks for reading!