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 OpenStack component is specifically responsible for event storage and querying (as opposed to metric/sample storage)? → Panko
2. Which component provides a web-based user interface for OpenStack? → Horizon
3. An instance is in 'ACTIVE' state but the user reports it is unreachable over SSH. The security group allows port 22. What should you check next? → Check iptables/nftables rules on the compute node for the instance's tap interface
4. Which OpenStack project provides a DNS-as-a-Service capability? → Designate
5. Which Nova mechanism allows an administrator to group compute hosts so that instances can be constrained or spread across physically isolated fault domains? → Availability zones
6. What does enabling 'port security' on a Neutron network enforce by default? → Prevents MAC and IP spoofing on all ports in the network
7. Which command lists all Cinder volume types available in an OpenStack deployment? → openstack volume type list
8. In the context of OpenStack Keystone federation, what does Identity Provider (IdP) federation allow? → Users from an external identity system to authenticate and receive OpenStack tokens
9. When should an issue be escalated to a higher support level? → When the issue exceeds your technical expertise or authorization level
10. What is required before launching a new instance in OpenStack? → Image, flavor, and network settings
11. Why is data validation important during integration? → It ensures data accuracy and consistency across connected systems
12. How does an admin list running instances across ALL projects using the OpenStack CLI? → openstack server list --all-projects
13. What is the recommended approach to prevent a 'noisy neighbor' issue where one tenant's workload monopolizes compute resources in OpenStack? → Using flavor extra specs with CPU pinning and NUMA topology policies
14. Which command would a cloud administrator use to create a new Keystone domain named 'engineering'? → openstack domain create engineering
15. In openstacksdk, which method is used to establish a connection to an OpenStack cloud using clouds.yaml? → openstack.connect()
16. Which Horizon dashboard panel provides administrators with visibility and control over all projects' resources? → Admin panel
17. Which Keystone feature allows an organization to use an external Identity Provider (IdP) such as Okta or Azure AD for OpenStack authentication? → Keystone federation with SAML2 or OIDC
18. What Neutron feature allows a single physical network interface to carry multiple tenant networks using 802.1Q tags? → VLAN provider network
19. What is the primary benefit of automating repetitive tasks? → Reduced human error and increased consistency of results
20. Which OpenStack service is responsible for providing a multi-tenant cloud messaging service? → Zaqar
21. What is capacity planning? → Predicting future resource needs based on growth trends and requirements
22. Which OpenStack project provides rating-as-a-service, calculating costs for resource usage? → Cloudkitty
23. What is the primary consideration when designing system architecture? → Scalability, reliability, and alignment with business requirements
24. Which Heat CLI command is used to create a new stack from a template file? → openstack stack create
25. What is the OpenStack service responsible for managing certificates and secrets as a dedicated key management service? → Barbican
26. In a typical OpenStack deployment, what is the purpose of the 'admin' endpoint type in the service catalog? → Used by services and administrators for privileged operations
27. What is a 'nested stack' in Heat orchestration? → A stack referenced as a resource within another template, enabling modular design
28. Which OpenStack service is responsible for managing virtual machine images? → Glance
29. An administrator wants to prevent a specific Keystone user from authenticating entirely without deleting their account. Which command should be used? → openstack user set --disable
30. Which Cinder feature allows administrators to set guaranteed IOPS or throughput limits on volumes? → Quality of Service (QoS) specs