openstack Nova explained

1. Nova Compute and Controller Services

2. 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.

3. 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.

5. Compute components
1. 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.

6. 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

7. 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.

8. 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.

9. 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.

10. 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.

11. 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.

12. 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

13. Thank you...