OpenStack Vskills 3 — Questions and Answers
Question 1: What does the 'nova evacuate' command do?
- Migrates a running VM to another host with zero downtime
- Moves instances off a failed compute host to another host (Correct answer)
- Deletes all instances on a host before maintenance
- Suspends all VMs on a compute node
Correct answer: Moves instances off a failed compute host to another host
nova evacuate rebuilds instances from a failed compute host onto another available host, recovering them after a node failure.
Question 2: Which Ceph storage pool type is recommended for OpenStack Cinder volumes in production?
- Erasure-coded pool with k=2, m=1
- Replicated pool with size=3 (Correct answer)
- Replicated pool with size=1
- Erasure-coded pool with k=8, m=3
Correct answer: Replicated pool with size=3
A replicated pool with size=3 (three copies) provides balanced performance and fault tolerance for block storage workloads.
Question 3: In OpenStack Neutron, what is the function of a 'security group'?
- Encrypting network traffic between instances
- Defining firewall rules controlling ingress and egress traffic to instances (Correct answer)
- Grouping projects for billing purposes
- Managing admin privileges for network operators
Correct answer: Defining firewall rules controlling ingress and egress traffic to instances
Security groups act as virtual firewalls, defining allowed inbound and outbound traffic rules applied to instance network ports.
Question 4: Which token format does modern Keystone (v3) use by default?
- UUID tokens
- PKI tokens
- Fernet tokens (Correct answer)
- SAML tokens
Correct answer: Fernet tokens
Fernet tokens are the default in modern Keystone as they are lightweight, encrypted, and do not require database persistence.
Question 5: What is the purpose of Heat's 'stack update' operation?
- Deleting and recreating a full stack from scratch
- Applying changes to an existing stack based on an updated template (Correct answer)
- Scaling out the number of compute nodes
- Validating a Heat template without deploying
Correct answer: Applying changes to an existing stack based on an updated template
stack update applies changes defined in a revised HOT template to an already-deployed stack, modifying only the affected resources.
Question 6: Which OpenStack service provides shared file systems (NFS/CIFS) to instances?
- Cinder
- Swift
- Manila (Correct answer)
- Barbican
Correct answer: Manila
Manila is the OpenStack Shared File Systems service, providing NFS, CIFS, and other protocol-based shared storage.
Question 7: What is the default scheduling algorithm used by Nova's filter scheduler?
- Round-robin across all compute hosts
- Weighted random selection after applying filters (Correct answer)
- Least-loaded host first without filtering
- Dedicated pinning based on flavor affinity
Correct answer: Weighted random selection after applying filters
The filter scheduler first applies a series of filters to eliminate ineligible hosts, then uses weighers to select the best candidate.
OpenStack Vskills 3
What does the 'nova evacuate' command do?