Architecture & System Design Flashcards
7 cards from real COA practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Architecture & System Design flashcards as text
Which OpenStack project provides a multi-region, geo-distributed block storage replication capability?
Answer: Cinder with Active-Active replication using a replicated backend
Cinder supports Active-Active volume replication when paired with a storage backend driver that implements the replication API, enabling cross-site data protection.
In an OpenStack deployment using OVN (Open Virtual Network), what replaces the traditional Neutron L3 agent?
Answer: Distributed routing implemented natively in OVN's logical router constructs
OVN implements distributed logical routers natively, eliminating the need for the traditional centralized Neutron L3 agent and enabling East-West routing on each hypervisor.
What is the role of the Glance image cache on compute nodes when configured with Nova?
Answer: It caches downloaded images locally to avoid repeated transfers from Glance on subsequent launches
The Nova image cache stores downloaded Glance images locally on compute nodes, speeding up subsequent instance launches by avoiding redundant network transfers.
Which design pattern does OpenStack use to allow services to discover endpoints for other services at runtime?
Answer: Keystone service catalog with endpoint URLs registered per service type and region
Each OpenStack service registers its API endpoints in the Keystone service catalog, which clients query at runtime to discover the correct URL for a given service and region.
In a large-scale OpenStack deployment, what is the primary reason for deploying the API services behind a load balancer (e.g., HAProxy)?
Answer: To distribute API request load across multiple API service instances for horizontal scalability and HA
A load balancer in front of API services enables horizontal scaling by distributing requests and provides failover if individual API service instances become unavailable.
When would you choose Octavia over the deprecated Neutron LBaaS v2 for load balancing in OpenStack?
Answer: For all production deployments, since Neutron LBaaS v2 has been removed and Octavia is the current load balancer service
Neutron LBaaS v2 was deprecated and removed; Octavia is now the official OpenStack Load Balancing service and should be used in all current deployments.
What architectural component allows OpenStack to support multiple hypervisor types (KVM, VMware, Hyper-V) simultaneously in the same deployment?
Answer: Nova's virt driver abstraction layer, with separate compute hosts running each hypervisor type
Nova uses a pluggable virt driver per compute host; each host runs one driver type, allowing a single Nova deployment to manage heterogeneous hypervisor environments.