azure

Four levels, and the two that matter operationally are the subscription, where quotas and billing live, and the resource group, which is the unit you delete. Getting the boundaries wrong is expensive to unpick later.

Service principal with a client secret is the answer people give and the one that leaves a credential in a config file. Managed identity is the same object with the secret handled by the platform.

One is layer 4 and regional, one is layer 7 and regional, one is layer 7 and global. Answer on those two axes and the choice makes itself, including when you need two of them together.

The private endpoint can be healthy while an office resolver still returns the public address. Trace the lookup from the failing client before changing access rules.

Moving a Kubernetes service account changes its token subject. Separate pod mutation, federation trust and Key Vault authorization before adding permissions.