OpenStack OpenStack Image Service (Glance) & Dashboard (Horizon) 1 — Questions and Answers
Question 1: Which OpenStack service stores and retrieves virtual machine disk images?
- Swift
- Cinder
- Glance (Correct answer)
- Nova
Correct answer: Glance
Glance is the OpenStack Image Service that stores, discovers, and retrieves VM disk images used to boot instances.
Question 2: What is OpenStack Horizon?
- A command-line interface for managing all OpenStack services
- A web-based dashboard providing a graphical interface to OpenStack services (Correct answer)
- A monitoring service for OpenStack infrastructure
- A configuration management tool for OpenStack deployments
Correct answer: A web-based dashboard providing a graphical interface to OpenStack services
Horizon is OpenStack's web-based dashboard that provides a GUI for users and administrators to interact with OpenStack services.
Question 3: Which disk image format is most commonly used for QEMU/KVM instances in OpenStack Glance?
- VMDK
- VHD
- QCOW2 (Correct answer)
- ISO
Correct answer: QCOW2
QCOW2 (QEMU Copy-On-Write version 2) is the standard disk image format for KVM-based OpenStack deployments.
Question 4: What is the 'visibility' property of a Glance image?
- Whether the image is stored in an encrypted format
- Controls who can see and use the image (public, private, shared, community) (Correct answer)
- The display resolution of the desktop image
- The network visibility zone where the image backend is accessible
Correct answer: Controls who can see and use the image (public, private, shared, community)
Glance image visibility controls access: 'public' images are available to all tenants, 'private' only to the owner.
Question 5: What is 'cloud-config' user data commonly used for when launching OpenStack instances?
- Configuring OpenStack service endpoints in the instance
- Providing declarative configuration instructions to cloud-init for automated instance setup (Correct answer)
- Setting up Nova placement constraints for the scheduler
- Defining Neutron network policies for the instance's interfaces
Correct answer: Providing declarative configuration instructions to cloud-init for automated instance setup
Cloud-config is a YAML format processed by cloud-init to perform automated instance configuration tasks at first boot.
Question 6: Where does Glance store image data by default in a basic OpenStack deployment?
- In the Nova ephemeral storage on compute nodes
- In the local filesystem of the Glance service node (Correct answer)
- In the Keystone database
- In a dedicated Neutron storage network
Correct answer: In the local filesystem of the Glance service node
By default, Glance stores image files in the local filesystem of the host running the Glance service, typically at /var/lib/glance/images/.
OpenStack OpenStack Image Service (Glance) & Dashboard (Horizon) 1
Which OpenStack service stores and retrieves virtual machine disk images?