An Azure Container Instance running a claims processing function requires a password at startup. The password must not be visible in the portal or container logs. What should be used?
Secure environment variables in Azure Container Instances (ACI) are designed to protect sensitive values by encrypting them at rest and masking them from standard display in the Azure portal, logs, and `az container show` output. When defined with the `secureValue` property, ACI ensures that the secret is injected into the container at runtime without being persistently exposed in plain text within the container's configuration. This mechanism significantly reduces the risk of accidental or malicious disclosure, making it the recommended approach for handling secrets directly within ACI.
Why this answer
Secure environment variables in Azure Container Instances are encrypted at rest and in transit, and are never exposed in the Azure portal, container logs, or to other users. This ensures the password remains confidential while being available to the container at startup, meeting the requirement of not being visible in the portal or logs.
Exam trap
The trap here is that candidates often confuse 'secure environment variables' with 'plain environment variables' or assume that command-line arguments are not logged, when in fact they are captured in container logs and visible in the portal.
How to eliminate wrong answers
Option A is wrong because plain environment variables are stored in plaintext and are visible in the Azure portal and container logs, violating the security requirement. Option C is wrong because a public blob containing the password would be accessible to anyone with the URL, completely compromising the password's confidentiality. Option D is wrong because container command-line arguments are logged in the container's startup logs and can be viewed in the portal, making them visible and insecure.