OpenStack OpenStack Storage (Cinder & Swift) 2 — Questions and Answers
Question 1: What is Ceph RBD commonly used for in OpenStack deployments?
- Providing DNS services to Neutron
- As a unified backend for Cinder block, Glance image, and Nova ephemeral storage (Correct answer)
- Running containerized OpenStack services
- Hosting the Keystone identity database
Correct answer: As a unified backend for Cinder block, Glance image, and Nova ephemeral storage
Ceph RBD (RADOS Block Device) is widely used as a unified storage backend for Cinder, Glance, and Nova in production OpenStack.
Question 2: What is the Swift 'ring' responsible for?
- Authenticating API requests to the object store
- Determining the placement of objects, containers, and accounts across storage nodes (Correct answer)
- Managing replication between Swift regions
- Routing HTTP requests to the correct proxy server
Correct answer: Determining the placement of objects, containers, and accounts across storage nodes
The Swift ring is a data structure that maps partition names to physical storage devices/nodes for data placement.
Question 3: Which Cinder feature allows a volume to be attached to multiple instances simultaneously (read/write)?
- Volume migration
- Multi-attach (Correct answer)
- Volume replication
- Volume transfer
Correct answer: Multi-attach
Cinder multi-attach allows a single volume to be attached to multiple VM instances at the same time for shared access.
Question 4: In Swift, what does the term 'consistency' refer to?
- All reads return the latest written data immediately (strong consistency)
- Swift uses eventual consistency where replicas sync asynchronously (Correct answer)
- All objects require a quorum write before acknowledging success
- Object checksums are verified on every read operation
Correct answer: Swift uses eventual consistency where replicas sync asynchronously
Swift uses an eventual consistency model where object replicas may temporarily be out of sync but converge over time.
Question 5: What is Cinder 'volume type' used for?
- Specifying the OS format (ext4, xfs) of the volume
- Defining storage characteristics (e.g., SSD, replicated, encrypted) for volume creation (Correct answer)
- Setting the maximum IOPS for all volumes globally
- Identifying volumes created by specific tenants
Correct answer: Defining storage characteristics (e.g., SSD, replicated, encrypted) for volume creation
Cinder volume types define storage quality-of-service characteristics like performance tier, replication level, or encryption.
Question 6: What protocol does Cinder most commonly use to present LVM-backed volumes to compute nodes?
- NFS
- Fibre Channel
- iSCSI (Correct answer)
- SMB
Correct answer: iSCSI
Cinder's LVM driver presents volumes to compute nodes via iSCSI (Internet Small Computer System Interface) by default.
OpenStack OpenStack Storage (Cinder & Swift) 2
What is Ceph RBD commonly used for in OpenStack deployments?