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Storing custom rules#

PSRule for Azure covers common use cases that align to the Microsoft Azure Well-Architected Framework (WAF). In addition to WAF alignment you may have a requirement to enforce organization specific rules.

For example:

  • Required tags on a resource group.
  • Code ownership for sensitive resource types.

PSRule allows custom rules to be layered on. These custom rules work side-by-side with PSRule for Azure.

Using a standard file path#

Rules can be standalone or packaged within a module. Standalone rules are ideal for a single project such as an Infrastructure as Code (IaC) repository. To reuse rules across multiple projects consider packaging these as a module.

The instructions for packaging rules in a module can be found here:

To store standalone rules we recommend that you:

  • Use .ps-rule/ — Create a sub-directory called .ps-rule in the root of your repository. Use all lower-case in the sub-directory name. Put any custom rules within this sub-directory.
  • Use files ending with .Rule.ps1 — PSRule uses a file naming convention to discover rules. We recommend using a file name that ends in .Rule.ps1.

Note

Build pipelines are often case-sensitive or run on Linux-based systems. Using the casing rule above reduces confusion latter when you configure continuous integration (CI).

Naming rules#

When running PSRule, rule names must be unique. PSRule for Azure uses the name prefix of Azure. on all rules and resources included in the module.

Example

The following names are examples of rules included within PSRule for Azure:

  • Azure.AKS.Version
  • Azure.AKS.AuthorizedIPs
  • Azure.SQL.MinTLS

When naming custom rules we recommend that you:

  • Use a standard prefix — You can use the Local. or Org. prefix for standalone rules.
    • Alternatively choose a short prefix that identifies your organization.
  • Use dotted notation — Use dots to separate rule name.
  • Use a maximum length of 35 characters — The default view of Invoke-PSRule truncates longer names. PSRule supports longer rule names however if Invoke-PSRule is called directly consider using Format-List.

Last update: 2021-07-27