Nova Compute and Controller Services

What is Nova compute & controller service?

•Nova Compute serves as the core of the Open Stack cloud

by providing virtual machines(instances) on demand.

•Nova controller node runs most of the nova services mainly

the Nova-scheduler which coordinates with other nova

services.

How it works?

• Nova supports the libvirt driver libvirtd that uses KVM as the

hypervisor. The hypervisor creates virtual machines and enables

live migration from node to node.

• It interacts with the Identity service to authenticate instance and

database access.

• It interacts with the Image service to access images and launch

instances.

• It interacts with the dashboard service to provide user and

administrative interface.

Compute components1. open stack-nova-api :- Handles requests and provides access to the Compute

services, such as booting an instance.

2. open stack-nova-cert:-Provides the certificate manager.

3. open stack-nova-compute:-Runs on each node to create and terminate virtual

instances. It interacts with the hypervisor to launch new instances, and ensures

that the instance state is maintained in the Compute database.

4. open stack-nova-conductor:-Provides database-access support for compute

nodes to reduce security risks.

5. open stack-nova-consoleauth:-Handles console authentication.

6. open stack-nova-network:-Network services that can serve as an alternative to

Neutron service and handle basic network traffic for private and public access.

7. open stack-nova-novncproxy:-Provides a VNC proxy for browsers to enable VNC

consoles to access virtual machines

8. open stack-nova-scheduler:-Dispatches requests for new virtual machines to

the correct node based on configured weights and filters.

COMPUTE RESOURCES

• Compute resources are the core of the Open Stack cloud. it is

recommended to consider physical and virtual resource

allocation, distribution, failover, and additional devices at the

time of open stack deployment.

• General considerations:-

1. Number of processors, memory, and storage in each hypervisor

2. Processor type

3. Resource nodes

4. Resource pools

5. Over-commit ratios

Number of processors, memory, and storage in each hypervisor

• The number of processor cores and threads directly affects the

number of worker threads that can run on a Compute node.

• Depending on the workload profile, additional Compute

resource pools can be added to the cloud later.

• you must determine the design based on the service and

based on a balanced infrastructure for all services.

Processor type

• Processor selection is an important consideration in

hardware design, especially when comparing the features

and performance characteristics of different processors.

• Processors can include features specifically for virtualized

compute hosts, such as hardware-assisted virtualization and

memory paging or EPT shadowing technology.

Resource nodes

• You must take into account Compute requirements of non-

hypervisor resource nodes in the cloud. Resource nodes

include the controller node and nodes that run Object

Storage, Block Storage and Networking services.

Resource pools

• Compute design should be chosen such that it will allocate

multiple pools of resources to be addressed on demand. It

maximizes application resource usage in the cloud.

• Hardware nodes selected for a Compute resource pool

should share a common processor, memory, and storage

layout. Choosing a common hardware design helps easier

deployment, support and node lifecycle maintenance.

Over-commit ratios• Open Stack enables users to over-commit CPU and RAM on

Compute nodes, which helps to increase the number of instances that run in the cloud. The over-commit ratio is the ratio of available virtual resources compared to the available physical resources.

1. The default CPU allocation ratio of 16:1 means that the scheduler allocates up to 16 virtual cores for every physical core.

2. The default RAM allocation ratio of 1.5:1 means that the scheduler allocates instances to a physical node if the total amount of RAM associated with the instances is less than 1.5 times the amount of RAM available on the physical node.

Things to remember

# Configuration file:-/etc/nova/nova.conf

# To check status of instance:- nova list

# To check list of images uploaded:- nova image-list

# To check available flavors:- nova flavor-list

# To check list of networks created:- nova net-list

# To check allocated floating IP to project:- nova floating –ip-list

#To check status of compute nodes:- nova service-list

Thank you...