OpenStack Core Components 3 — Questions and Answers
Question 1: In OpenStack, what is the role of the 'nova-scheduler' component?
- Allocating floating IPs to instances
- Selecting the compute host for a new instance (Correct answer)
- Scheduling image uploads to Glance
- Managing Cinder volume attachment timing
Correct answer: Selecting the compute host for a new instance
nova-scheduler evaluates compute hosts against configured filters and weights to determine the best host for a new VM.
Question 2: What is the purpose of a Keystone 'endpoint' in OpenStack?
- A DNS record for a service's hostname
- A URL registered in the service catalog for a specific service and region (Correct answer)
- A VIP managed by HAProxy
- A Neutron floating IP attached to a service
Correct answer: A URL registered in the service catalog for a specific service and region
Keystone endpoints are URLs stored in the service catalog that clients use to reach a specific OpenStack service in a given region.
Question 3: Which Neutron agent is responsible for applying security group rules on compute nodes?
- neutron-dhcp-agent
- neutron-metadata-agent
- neutron-l3-agent
- neutron-openvswitch-agent (Correct answer)
Correct answer: neutron-openvswitch-agent
The neutron-openvswitch-agent (or linuxbridge-agent) runs on compute nodes and enforces security group rules via iptables or OVS flows.
Question 4: What does 'Cinder' provide in an OpenStack deployment?
- Ephemeral instance storage
- Block storage volumes attachable to instances (Correct answer)
- Object storage with eventual consistency
- Shared file system access
Correct answer: Block storage volumes attachable to instances
Cinder is the OpenStack Block Storage service that provides persistent block volumes that can be attached to and detached from Nova instances.
Question 5: Which OpenStack service provides object storage with high durability through replication?
- Cinder
- Manila
- Swift (Correct answer)
- Glance
Correct answer: Swift
Swift is OpenStack's Object Storage service that stores unstructured data with configurable replication for high durability.
Question 6: In OpenStack Heat, what file format is used to define infrastructure templates?
- JSON only
- XML
- YAML (HOT format) (Correct answer)
- Terraform HCL
Correct answer: YAML (HOT format)
Heat Orchestration Templates (HOT) are written in YAML and describe stacks of OpenStack resources to be provisioned together.
Question 7: What is the function of the nova-conductor service?
- Routes API requests to appropriate compute nodes
- Mediates database access for compute nodes and prevents direct DB access (Correct answer)
- Generates SSL certificates for inter-service communication
- Manages the live migration of instances between hosts
Correct answer: Mediates database access for compute nodes and prevents direct DB access
nova-conductor acts as a database proxy so compute nodes never access the database directly, improving security and scalability.
OpenStack Core Components 3
In OpenStack, what is the role of the 'nova-scheduler' component?