Quick Answer
The answer is primary and secondary keys, along with Azure RBAC, as the two valid methods to secure access to Azure Cosmos DB. Primary and secondary keys function as master keys granting full administrative access to the account, while Azure RBAC enables fine-grained, role-based control over data plane operations without exposing the keys. On the Microsoft Azure Solutions Architect Expert AZ-305 exam, this topic tests your ability to distinguish Cosmos DB’s native authentication options from those of other Azure services, with a common trap being the confusion of Shared Access Signatures (SAS) or certificates—both of which apply to Azure Storage, not Cosmos DB. Remember that Cosmos DB relies on key-based or identity-based authentication (like managed identities and Microsoft Entra ID), not token-based SAS. A helpful memory tip: “Cosmos uses keys and roles, not SAS or scrolls.”
This AZ-305 practice question tests your understanding of design data storage solutions. Match the stated requirement to the specific cloud service, access model, or configuration option — many options are valid in isolation but not for this scenario. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
Which TWO options are valid methods to secure access to Azure Cosmos DB?
X.509 certificate-based authentication
Why wrong: Not natively supported.
Azure Storage account keys
Why wrong: Storage account keys are for Azure Storage, not Cosmos DB.
Azure RBAC roles
RBAC can control access to Cosmos DB accounts.
Primary and secondary keys
Keys can be used to authenticate requests.
Shared access signatures (SAS)
Why wrong: SAS is not supported for Cosmos DB.
Answer choices
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
Azure RBAC roles
Cosmos DB supports primary/secondary keys, Azure RBAC, managed identities, and Microsoft Entra ID authentication. Option A is correct because primary keys provide access. Option B is correct because RBAC can be used for fine-grained access control. Option C is wrong because SAS tokens are not used for Cosmos DB; they are for Azure Storage. Option D is wrong because certificates are not a native authentication method. Option E is wrong because shared access signatures are for storage, not Cosmos DB.
Key principle: NAT direction and interface roles matter as much as the IP address mapping. Inside/outside designation controls which traffic is translated.
Answer analysis
For each option: why learners choose it and why it is or isn't the right answer here.
X.509 certificate-based authentication
Why it's wrong here
Not natively supported.
Azure Storage account keys
Why it's wrong here
Storage account keys are for Azure Storage, not Cosmos DB.
Azure RBAC roles
Why this is correct
RBAC can control access to Cosmos DB accounts.
Related concept
Static NAT maps one inside address to one outside address.
Primary and secondary keys
Why this is correct
Keys can be used to authenticate requests.
Related concept
Static NAT maps one inside address to one outside address.
Shared access signatures (SAS)
Why it's wrong here
SAS is not supported for Cosmos DB.
Common exam traps
NAT is not only about the public address. The inside/outside interface roles and the ACL or rule that matches traffic are just as important.
Detailed technical explanation
NAT questions usually test address translation, overload/PAT behaviour, static mappings and whether the right traffic is being translated. Read the interface direction and address terms carefully.
Key takeaway
NAT direction and interface roles matter as much as the IP address mapping. Inside/outside designation controls which traffic is translated.
Real-world example
A media company stores terabytes of video archives that are accessed once a year for audit purposes. Moving these objects to a cold storage tier (Azure Archive, S3 Glacier, or Google Nearline) costs a fraction of hot storage. Questions like this test whether you understand storage tiers, access frequency tradeoffs, and retrieval latency requirements.
What to study next
Review the four NAT address types (inside local, inside global, outside local, outside global), PAT port overload, and static vs dynamic NAT use cases. Then practise related AZ-305 NAT questions on configuration and troubleshooting.
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FAQ
Design data storage solutions — This question tests Design data storage solutions — Static NAT maps one inside address to one outside address..
The correct answer is: Azure RBAC roles — Cosmos DB supports primary/secondary keys, Azure RBAC, managed identities, and Microsoft Entra ID authentication. Option A is correct because primary keys provide access. Option B is correct because RBAC can be used for fine-grained access control. Option C is wrong because SAS tokens are not used for Cosmos DB; they are for Azure Storage. Option D is wrong because certificates are not a native authentication method. Option E is wrong because shared access signatures are for storage, not Cosmos DB.
Review the four NAT address types (inside local, inside global, outside local, outside global), PAT port overload, and static vs dynamic NAT use cases. Then practise related AZ-305 NAT questions on configuration and troubleshooting.
Static NAT maps one inside address to one outside address.
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Last reviewed: Jun 21, 2026
This AZ-305 practice question is part of Courseiva's free Microsoft certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the AZ-305 exam.
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