Service principals for applications in Azure - Step-by-Step Execution

Process Flow - Service principals for applications

Create Application Registration

↓

Generate Service Principal

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Assign Roles/Permissions

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Use Service Principal for Auth

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Access Azure Resources

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Done

This flow shows how an application gets a service principal, which is like its identity, then gets permissions to access Azure resources.

Execution Sample

Azure

az ad sp create-for-rbac --name MyAppSP --role Contributor --scopes /subscriptions/12345

This command creates a service principal named MyAppSP with Contributor role on a subscription.

Process Table

Step	Action	Input/Command	Result	Notes
1	Create Application Registration	az ad app create --display-name MyApp	App registered with appId	AppId is unique app identity
2	Create Service Principal	az ad sp create --id <appId>	Service principal created	SP links to appId
3	Assign Role	az role assignment create --assignee <spId> --role Contributor --scope /subscriptions/12345	Role assigned	SP can access resources
4	Use SP Credentials	Use clientId and secret to auth	Token received	Token used to call Azure APIs
5	Access Resources	Call Azure API with token	Access granted	SP acts as app identity
6	End		Process complete	Service principal ready for app use

💡 After step 5, the service principal can authenticate and access resources as assigned.

Status Tracker

Variable	Start	After Step 1	After Step 2	After Step 3	After Step 4	Final
appId	None	Generated appId	Same appId	Same appId	Same appId	Same appId
spId	None	None	Generated spId	Same spId	Same spId	Same spId
roleAssignment	None	None	None	Contributor role assigned	Contributor role assigned	Contributor role assigned
authToken	None	None	None	None	Token received	Token valid for API calls

Key Moments - 3 Insights

Why do we need both an application registration and a service principal?

The application registration defines the app's identity globally, while the service principal is the local identity in a tenant used to assign permissions. See execution_table rows 1 and 2.

What happens if we skip assigning a role to the service principal?

Without a role assignment (row 3), the service principal cannot access Azure resources even if it exists.

How does the service principal authenticate to Azure?

It uses its clientId and secret or certificate to get an auth token (row 4), which is then used to access resources.

Visual Quiz - 3 Questions

Look at the execution_table, at which step is the service principal created?

A Step 1

B Step 3

C Step 2

D Step 4

💡 Hint

Check the 'Action' column for 'Create Service Principal' in execution_table.

According to variable_tracker, when does the authToken variable get a value?

A After Step 2

B After Step 4

C After Step 3

D After Step 5

💡 Hint

Look at the 'authToken' row and see when it changes from None.

If the role assignment is missing, what will happen when the service principal tries to access resources?

A Access will be denied

B Access will be granted

C Authentication will fail

D Service principal will be deleted

💡 Hint

Refer to key_moments about role assignment importance and execution_table row 3.

Concept Snapshot

Service principals are identities for apps in Azure.
Create an app registration first.
Create a service principal linked to the app.
Assign roles to the service principal.
Use its credentials to authenticate and access resources.
This enables secure app access without user accounts.

Full Transcript

Service principals are like user accounts but for applications. First, you register your application in Azure Active Directory to get an app ID. Then, you create a service principal which acts as the app's identity in your tenant. Next, you assign roles to this service principal to give it permissions to Azure resources. The app uses the service principal's credentials to get an authentication token. This token lets the app access Azure resources securely. Without role assignments, the service principal cannot access resources even if it exists. This process ensures apps can authenticate and act securely without needing user credentials.