OpenStack Compute (Nova) Flashcards

Which Nova scheduler filter ensures that a VM is placed on a host with enough RAM?

Answer: RamFilter

The RamFilter in the Nova scheduler eliminates compute hosts that do not have sufficient available RAM for the requested instance.

What is the purpose of Nova's 'resize' operation?

Answer: Changing a VM's flavor to one with different vCPU/RAM/disk specifications

Nova resize allows changing a VM's flavor (compute resources like vCPUs and RAM) by migrating it to a host that can accommodate the new flavor.

What does the Nova metadata service at 169.254.169.254 provide to instances?

Answer: Instance metadata like hostname, public keys, and user-data scripts

The Nova metadata service provides instance-specific data like SSH keys, user-data, and instance attributes accessible from within the VM.

What is 'nova-placement' (Placement API) responsible for in OpenStack?

Answer: Tracking resource inventories and allocations across compute nodes for scheduling decisions

The Placement API tracks resource inventories (CPU, RAM, disk, custom resources) and allocations to enable accurate Nova scheduling decisions.

What OpenStack command boots a new instance named 'web01' using a specific image and flavor?

Answer: openstack server create --image --flavor web01

The modern OpenStack CLI uses 'openstack server create' with --image and --flavor flags to boot a new VM instance.

What is 'NUMA topology' awareness in Nova compute scheduling?

Answer: Scheduling VM vCPUs and memory to align with physical NUMA nodes to improve performance

NUMA-aware scheduling in Nova pins VM vCPUs and RAM to specific physical NUMA nodes to minimize cross-NUMA memory access latency.