COA Cheat Sheet 2026

The 30 highest-yield COA facts, distilled from real exam questions. Print it, save it as a PDF, or study it here — free, no sign-up.

1. Which component provides a web-based user interface for OpenStack? → Horizon
2. When should an issue be escalated to a higher support level? → When the issue exceeds your technical expertise or authorization level
3. What is required before launching a new instance in OpenStack? → Image, flavor, and network settings
4. Why is data validation important during integration? → It ensures data accuracy and consistency across connected systems
5. How does an admin list running instances across ALL projects using the OpenStack CLI? → openstack server list --all-projects
6. Which Horizon dashboard panel provides administrators with visibility and control over all projects' resources? → Admin panel
7. What is the primary benefit of automating repetitive tasks? → Reduced human error and increased consistency of results
8. What is capacity planning? → Predicting future resource needs based on growth trends and requirements
9. What is the primary consideration when designing system architecture? → Scalability, reliability, and alignment with business requirements
10. Which Heat CLI command is used to create a new stack from a template file? → openstack stack create
11. What is a 'nested stack' in Heat orchestration? → A stack referenced as a resource within another template, enabling modular design
12. Which OpenStack service is responsible for managing virtual machine images? → Glance
13. Why is regular security training important for all staff? → Employees are often the weakest link in security and training reduces human error
14. What role does Neutron play in OpenStack? → Provides networking services
15. How do you add a custom metadata property to a Glance image using the unified OpenStack CLI? → openstack image set --property key=value
16. When should architectural decisions be reviewed and potentially revised? → When requirements change significantly or performance targets are not met
17. What does the 'openstack stack show' command display for a given stack? → Detailed information including status, creation time, parameters, and outputs
18. What is the 80/20 rule as applied to performance optimization? → 80% of performance gains come from optimizing 20% of the code or configuration
19. What is the primary function of Keystone in OpenStack? → Identity and access management
20. What is the benefit of using a layered architecture approach? → Separation of concerns enabling independent development and testing
21. What is the recommended approach for deploying system updates? → Incremental rollouts with rollback plans and monitoring
22. Which top-level section of a HOT template defines the version of the template format? → heat_template_version
23. Where in Horizon can you access both the console log output and the interactive VNC console for an instance? → Both the Actions menu and a dedicated Console tab
24. What is the function of Cinder in OpenStack? → Block storage service
25. How are users authenticated in OpenStack? → Using Keystone-issued tokens
26. What is the primary function of VRRP in Neutron's L3 HA router implementation? → Providing automatic failover from an active router to a standby router
27. What is the key difference between `nova evacuate` and `nova host-evacuate`? → host-evacuate moves all instances from a specified host at once
28. How do you authenticate the OpenStack CLI by loading environment variables from a credentials file? → source openrc.sh
29. What is a 'stack' in the context of OpenStack Heat? → A collection of resources instantiated from a Heat template
30. What is a project in OpenStack security context? → An isolated group for user access and resources