Context
In most demos and tutorials about Azure (and not just that) you will find a variety of resources provisioned in "fast / light" mode, that is to say without being super strict on concepts such as naming artifacts. "WebApp1", "MyVM", "MyRG" are names commonly found in demonstrations or even the "Proof-of-Concepts" (which are supposed to be much more than basic demos).No particular concern at this point, we're supposed to be focused on the principles and concepts of the demo involved. But what about what about naming Azure artifacts when moving to a real project or an application to put into production? How do we ensure that the names we choose will be well in tune with the architectural complex context, environment, safety, operation of this application, project or system?
Naming in IT projects
First, the notion of strict naming is not specific to Azure; each IT project should follow a set of naming rules, rules that will help to properly structure the project, easily find the terms we already knew before, or even be able to identify resources exposed in lists not always structured. Naming rules are present in each programming language, in each infrastructure provisioning.That said, there are concepts specific to the cloud (even specific to Azure) which will complement the already existing concepts. We must first catalog the list of naming aspects that is applicable for our organization, our project and our cloud.
Key principles:
Today, who said cloud, said agile mind. The cloud itself (and the public cloud in particular) is agile by his speed provisioning, scaling elasticity, and especially its fast pace of updates and new features. To respect this spirit, rules must accept flexibility. One should not be blocked to deploy a prototyping environment because, for example, the project name has not been clearly defined, or the type of artifact or resource is fresh in the cloud; however, even in this case, we should be able to easily understand afterwards in what context the resource was provisioned (if only for environment deprovisioning to avoid Azure consumption). This article will not try, so, to impose a set of rules as universal, but rather guide you how to define your own set of rules and then apply. That said, we still try to exemplify concretely (and for those who will see the example very close to their cases, apply directly the model in its state). Finally, the last "disclaimer", the dynamic spirit of the Azure will make possible that certain rules or constraints no longer apply (or are different) at the time of reading. In this case, a feedback from you will be very useful for the update of the article.What’s a name of an Azure resource?
Let’s start from the base: the name of a resource Azure represents a string which allows unique identification of the Azure resource.The very general vision of this definition stops here:
- The name itself can be a simple "code" unique, or may correspond to a "namespace" (ex. Azure Service Bus), an "account name" (ex. Azure Storage), a "hostname" (ex. Azure VM) or other specific significance to the type of resource
- Unique identification, where? Names can have a context (scope) global public (eg. Based on an Azure subdomain, like the Azure Service Bus namespaces, Azure Storage accounts etc.), local to the subscription (eg. Azure VNET) or local to the parent resource (ex. the names of files or blobs in Azure Blob Storage container)
- To further complicate the task, some types of resources have naming rules different for different types within the same type (difficult to understand? example: the Azure VMs have stronger constraints - maximum 15 characters - for VMs based on Windows, than on Linux. Historical issue, of course, coming from on-premises infrastructure, but that is reflected in the cloud naming).
- The characters allowed in names also vary; but we can identify some sets of applicable characters - like below (but not limited to):
- Alphanumeric (numbers and letters)
- Alphanumeric plus underscore and dash
- Alphanumeric plus underscore, dash and dot
- Any character allowed in a URI
- Any character
- The majority of names cannot begin or end with a hyphen or underscore
- Also, a particular point is the variability of case sensitivity:
- Case sensitive names (ex. blob names in Azure Storage container)
- Case insensitive names (eg. resource groups)
- Mandatory lowercase names (eg. the Azure Storage accounts)
- Length constraints are widely varying – both on the lower limit and the upper one. Certain names require between 1-64 characters other between 1-80, 2-80, 1-1024 etc.. Very, very variable, therefore, no specific marker on this.
Hence once again the importance of this naming structuring task. It is not unusual that you start with the rules that you consider sufficient (for the types of resources you deal with at that time) and which fall blocking for the naming of the very new resource you need in your project).
Naming constraints for Azure resources
To give you a more accurate and centralized reference for these constraints, here they are (compiled from the Azure documentation and following the requirements outlined in the resources creation process):| Resource or artifact | Context (Scope) | Min len | Max len | Case | Valid character set |
| Resource Group | Global | 1 | 64 | Insensitive | Alphanumeric, underscore and hyphen |
| Availability Set | Resource Group | 1 | 80 | Insensitive | Alphanumeric, underscore and hyphen |
| Virtual Machine (Windows) | Resource Group | 1 | 15 | Insensitive | Alphanumeric, underscore and hyphen |
| Virtual Machine (Linux) | Resource Group | 1 | 64 | Insensitive | Alphanumeric, underscore and hyphen |
| Storage account | Global | 3 | 24 | Lower cap | Alphanumeric |
| Azure Storage Container | Storage account | 3 | 63 | Lower cap | Alphanumeric and hyphen |
| Azure Storage Blob | Container | 1 | 1024 | Sensitive | URL characters |
| Azure Storage Queue | Storage account | 3 | 63 | Lower cap | Alphanumeric and hyphen |
| Azure Storage Table | Storage account | 3 | 63 | Insensitive | Alphanumeric |
| Azure Storage File | Storage account | 3 | 63 | Lower cap | Alphanumeric |
| Virtual Network (VNet) | Resource Group | 2 | 64 | Insensitive | Alphanumeric, underscore, hyphen and point |
| Network Subnet | Parent VNet | 2 | 64 | Insensitive | Alphanumeric, underscore, hyphen and point |
| Network Interface | Resource Group | 1 | 80 | Insensitive | Alphanumeric, underscore, hyphen and point |
| Network Security Group | Resource Group | 1 | 80 | Insensitive | Alphanumeric, underscore, hyphen and point |
| Network Security Group Rule | Resource Group | 1 | 80 | Insensitive | Alphanumeric, underscore, hyphen and point |
| Route table | Resource Group | 1 | 80 | Insensitive | Alphanumeric, underscore, hyphen and point |
| ExpressRoute Circuit | Resource Group | 1 | 80 | Insensitive | Alphanumeric, underscore, hyphen and point |
| Public IP Address | Resource Group | 1 | 80 | Insensitive | Alphanumeric, underscore, hyphen and point |
| Load Balancer | Resource Group | 1 | 80 | Insensitive | Alphanumeric, underscore, hyphen and point |
| Load Balanced Rules Config | Load Balancer | 1 | 80 | Insensitive | Alphanumeric, underscore, hyphen and point |
| App Service Plan | Subscription | 2 | 40 | Insensitive | Alphanumeric |
| Web App | Global | 2 | 60 | Insensitive | Alphanumeric and hyphen |
| Function | Global | 2 | 60 | Insensitive | Alphanumeric and hyphen |
| Mobile App | Global | 2 | 60 | Insensitive | Alphanumeric and hyphen |
| Logic App | Global | 2 | 60 | Insensitive | Alphanumeric and hyphen |
| API App | Global | 2 | 60 | Insensitive | Alphanumeric and hyphen |
| App Service Environment | Global | 2 | 60 | Insensitive | Alphanumeric and hyphen |
| App Service Certificate | Global | 3 | 15 | Insensitive | Alphanumeric |
| API Management | Global | 1 | 50 | Insensitive | Alphanumeric |
| Notification Hub | Subscription | 1 | 260 | Insensitive | Alphanumeric, underscore, hyphen and point |
| Notification Hub Namespace | Global | 2 | 50 | Insensitive | Alphanumeric and hyphen |
| SQL Database | Subscription | 1 | 28 | Insensitive | Alphanumeric, underscore and hyphen |
| SQL Server | Global | 1 | 63 | Lower cap | Alphanumeric and hyphen |
| SQL Data Warehouse Database | Subscription | 1 | 28 | Insensitive | Alphanumeric, underscore and hyphen |
| Document DB | Global | 3 | 50 | Lower cap | Alphanumeric and hyphen |
| Redis Cache | Global | 1 | 63 | Insensitive | Alphanumeric and hyphen |
| Search Service | Global | 2 | 60 | Lower cap | Alphanumeric and hyphen |
| Power BI Workspace Collection | Subscription | 3 | 64 | Insensitive | Alphanumeric and hyphen |
| Cognitive Services Account | Subscription | 2 | 64 | Insensitive | Alphanumeric, underscore and hyphen |
| Data Catalog | Subscription | 2 | 26 | Insensitive | Alphanumeric |
| HDInsight Cluster | Global | 1 | 59 | Insensitive | Alphanumeric and hyphen |
| Machine Learning Workspace | Subscription | 3 | 24 | Insensitive | Alphanumeric and hyphen |
| Data Factory | Subscription | 3 | 64 | Insensitive | Alphanumeric and hyphen |
| Event Hub | Subscription | 1 | 50 | Insensitive | Alphanumeric, underscore and hyphen |
| Service Bus Namespace | Global | 6 | 50 | Insensitive | Alphanumeric and hyphen |
| Service Bus Queue | Subscription | 1 | 50 | Insensitive | Alphanumeric, underscore and hyphen |
| Service Bus Topic | Subscription | 1 | 50 | Insensitive | Alphanumeric, underscore and hyphen |
| Stream Analytics Job | Subscription | 3 | 63 | Insensitive | Alphanumeric and hyphen |
| IoT Hub | Subscription | 3 | 50 | Insensitive | Alphanumeric and hyphen |
| Traffic Manager | Global | 1 | 63 | Insensitive | URL characters |
| Media Service Account | Global | 3 | 24 | Lower cap | Alphanumeric |
| CDN Profile | Global | 1 | ? | Insensitive | Alphanumeric and hyphen |
| Azure AD Domain | Global | 1 | 27 | Insensitive | Alphanumeric |
| Azure AD | Subscription | 1 | 256 | Insensitive | Any character |
| Team Services Account | Global | 1 | 50 | Insensitive | Alphanumeric and hyphen |
| Team Project | Account | 1 | 65 | Insensitive | Alphanumeric and hyphen |
| DevTest Labs | Subscription | 1 | 27 | Insensitive | Alphanumeric, underscore, hyphen and parenthesis |
| Application Insights | Subscription | 1 | 255 | Insensitive | Any except 3 characters |
| Automation Account | Subscription | 6 | 50 | Insensitive | Alphanumeric and hyphen |
| Recovery Services Vault | Subscription | 2 | 50 | Insensitive | Alphanumeric and hyphen |
| Scheduler Job | Subscription | 1 | 260 | Insensitive | Alphanumeric, underscore and hyphen |
| Scheduler Job Collection | Subscription | 1 | 100 | Insensitive | Alphanumeric, underscore and hyphen |
| Cloud Service | Global | 1 | 63 | Insensitive | Alphanumeric and hyphen |
| Batch Account | Global | 3 | 24 | Lower cap | Alphanumeric |
| BizTalk Service | Global | 6 | 20 | Lower cap | Alphanumeric |
| Mobile Engagement Collection | Global | 2 | 50 | Insensitive | Alphanumeric and hyphen |
| Mobile Engagement App Resource | Global | 1 | 50 | Insensitive | Alphanumeric, underscore and hyphen |
| Mobile Engagement Application | Subscription | 1 | ? | Insensitive | Any character |
| RemoteApp Collection | Subscription | 3 | 13 | Insensitive | Alphanumeric |
| Key Vault | Global | ? | ? | Insensitive | Alphanumeric and hyphen |
| Operations Mgmt Suite Namespace | Global | 4 | 24 | Insensitive | Alphanumeric and hyphen |
| Tag Name | Resource | 1 | 512 | Insensitive | Alphanumeric |
| Tag Value | Resource | 1 | 256 | Insensitive | Alphanumeric |
