OpenStack Core Components 5 — Questions and Answers
Question 1: What is the role of the 'neutron-l3-agent' in an OpenStack deployment?
- Assigns MAC addresses to virtual ports
- Provides Layer 3 routing and floating IP NAT between networks (Correct answer)
- Monitors OVS bridge health
- Synchronizes Neutron DB with Nova
Correct answer: Provides Layer 3 routing and floating IP NAT between networks
The neutron-l3-agent manages virtual routers on network nodes, performing routing between tenant subnets and NAT for floating IPs.
Question 2: In OpenStack, what does 'live migration' allow an operator to do?
- Move a volume between storage backends without downtime
- Transfer a running VM from one compute host to another with minimal interruption (Correct answer)
- Promote a snapshot to a base image without stopping the instance
- Replicate a tenant network to a second region
Correct answer: Transfer a running VM from one compute host to another with minimal interruption
Live migration moves a running instance between compute hosts while it continues to serve traffic, useful for host maintenance.
Question 3: Which storage protocol is most commonly used when attaching a Cinder volume to a Nova instance in production?
- NFS
- iSCSI (Correct answer)
- SMB
- SFTP
Correct answer: iSCSI
iSCSI is the most widely used protocol for attaching Cinder block volumes to Nova instances, transporting SCSI commands over TCP/IP.
Question 4: What is the purpose of a Glance 'image property' (metadata)?
- Defining the network topology for instances launched from the image
- Storing key-value pairs that describe the image and influence scheduler behavior (Correct answer)
- Setting the RBAC policy on who can launch the image
- Specifying the Cinder backend to use for the root volume
Correct answer: Storing key-value pairs that describe the image and influence scheduler behavior
Glance image properties are arbitrary key-value metadata attached to images that can influence Nova scheduling, driver behavior, and filtering.
Question 5: Which OpenStack service provides auto-scaling and orchestration of application stacks?
- Senlin
- Mistral
- Heat (Correct answer)
- Congress
Correct answer: Heat
Heat provides stack orchestration and supports auto-scaling policies via integration with Ceilometer/Aodh to grow or shrink resource groups.
Question 6: In Keystone's RBAC model, what is a 'role assignment'?
- Granting a role to a user or group on a specific project or domain (Correct answer)
- Assigning an IP address role to a Neutron port
- Mapping a service to its endpoint in the catalog
- Configuring the token expiry duration for a role
Correct answer: Granting a role to a user or group on a specific project or domain
A role assignment links a Keystone role (e.g., 'admin', 'member') to a user or group scoped to a project or domain, determining what actions they can perform.
Question 7: What is the function of the OpenStack 'placement' service (originally part of Nova)?
- Placing floating IPs onto instances automatically
- Tracking resource provider inventories and allocations for scheduling decisions (Correct answer)
- Placing boot images onto compute host local disks
- Mapping tenant IDs to specific hardware zones
Correct answer: Tracking resource provider inventories and allocations for scheduling decisions
The Placement API tracks resource providers (compute nodes, shared storage) and their allocations, enabling the Nova scheduler to make accurate placement decisions.
OpenStack Core Components 5
What is the role of the 'neutron-l3-agent' in an OpenStack deployment?