Nova in OpenStack

What is nova?

Nova is the OpenStack project that provides a way to provision compute instances (aka virtual servers). Nova supports creating virtual machines, bare-metal servers (through the use of ironic), and has limited support for system containers. Nova runs as a set of daemons on top of existing Linux servers to provide that service.

Nova System Architecture

• DB: sql database for data storage.
• API: component that receives HTTP requests, converts commands and communicates with other components via the oslo.messaging queue or HTTP.
• Scheduler: decides which host gets each instance.
• Compute: manages communication with hypervisor and virtual machines.
• Conductor: handles requests that need coordination (build/resize), acts as a database proxy, or handles object conversions.
• Placement: tracks resource provider inventories and usages.

Lets implementing nova module

1- Create the Compute service credentials:

Create the nova user:

#openstack user create --domain default --project PROJECTNAME --password-prompt nova

Add the admin role to the nova user:

#openstack role add --project PROJECTNAME --user nova admin

Create the nova service entity:

#openstack service create --name nova \
  --description "OpenStack Compute" compute

2-Create the Compute API service endpoints:

#openstack endpoint create --region RegionOne \
  compute public http://controller:8774/v2.1
#openstack endpoint create --region RegionOne \
  compute internal http://controller:8774/v2.1
#openstack endpoint create --region RegionOne \
  compute admin http://controller:8774/v2.1

Create Database

you must create a database, service credentials, and API endpoints for nova,nova_api,nova_cell0,placement.

# mysql -u root -p
MariaDB [(none)]>create database nova;
MariaDB [(none)]>create database nova_api;
MariaDB [(none)]>create database nova_cell0;

MariaDB [(none)]>grant all privileges on nova.* to nova@'%' identified by 'NOVA_DBPASS';
MariaDB [(none)]>grant all privileges on nova.* to nova@'localhost' identified by 'NOVA_DBPASS';
MariaDB [(none)]>grant all privileges on nova_api.* to nova@'%' identified by 'NOVA_DBPASS';
MariaDB [(none)]>grant all privileges on nova_api.* to nova@'localhost' identified by 'NOVA_DBPASS';
MariaDB [(none)]>grant all privileges on nova_cell0.* to nova@'%' identified by 'NOVA_DBPASS';
MariaDB [(none)]>grant all privileges on nova_cell0.* to nova@'localhost' identified by 'NOVA_DBPASS';

Install and configure components

# yum --enablerepo=centos-openstack-train install openstack-nova-api openstack-nova-conductor openstack-nova-console openstack-nova-novncproxy openstack-nova-scheduler

Edit the /etc/nova/nova.conf file and complete the following actions:

In the [DEFAULT] section, configure the my_ip option to use the management interface IP address of the controller node:

my_ip = management ip(controller ip)

set management ip whether for controller or computer.

In production environments, we must have at least two of these IPs.

In the [DEFAULT] section, enable only the compute and metadata APIs:

[DEFAULT]
# ...
enabled_apis = osapi_compute,metadata

metadata works between nova and neutron.

The top-level directory for maintaining Nova’s state.

[DEFAULT]
# ...
state_path=/var/lib/nova

In the [oslo_concurrency] section, configure the lock path:

[oslo_concurrency]
# ...
lock_path = /var/lib/nova/tmp

In the [DEFAULT] section, configure RabbitMQ message queue access:

[DEFAULT]
# ...
transport_url = rabbit://openstack:RABBIT_PASS@controller:5672/

• Replace RABBIT_PASS with the password you chose for the openstack account in RabbitMQ.

In the [glance] section, configure the location of the Image service API:

[glance]
# ...
api_servers = http://controller:9292

In the [api] and [keystone_authtoken] sections, configure Identity service access:

[api]
# ...
auth_strategy = keystone

[keystone_authtoken]
# ...
www_authenticate_uri = http://controller:5000/
auth_url = http://controller:5000/
memcached_servers = controller:11211
auth_type = password
project_domain_name = Default
user_domain_name = Default
project_name = service
username = nova
password = NOVA_PASS

Replace NOVA_PASS with the password you chose for the nova user in the Identity service.

In the [placement] section, configure access to the Placement service:

[placement]
# ...
region_name = RegionOne
project_domain_name = Default
project_name = service
auth_type = password
user_domain_name = Default
auth_url = http://controller:5000/v3
username = placement
password = PLACEMENT_PASS

• Replace PLACEMENT_PASS with the password you choose for the placement service user created when installing Placement. Comment out or remove any other options in the [placement] section.

In the [api_database] and [database] sections, configure database access:

[api_database]
# ...
connection = mysql+pymysql://nova:NOVA_DBPASS@controller/nova_api

[database]
# ...
connection = mysql+pymysql://nova:NOVA_DBPASS@controller/nova

In the [vnc] section, configure the VNC proxy to use the management interface IP address of the controller node:

[vnc]
enabled = true
# ...
server_listen = $my_ip
server_proxyclient_address = $my_ip

Public address of noVNC VNC console proxy.

[vnc]
novncproxy_base_url=http://controller:6080/vnc_auto.html

Private, internal IP address or hostname of VNC console proxy.

[vnc]
server_proxyclient_address=controller

🌗This option represents a file name for the paste.deploy config for nova-api.

api_paste_config=api-paste.ini

Populate the nova-api database:

su -s /bin/sh -c "nova-manage api_db sync" nova

Ignore any deprecation messages in this output.

Register the cell0 database:

# su -s /bin/sh -c "nova-manage cell_v2 map_cell0" nova

Create the cell1 cell:

# su -s /bin/sh -c "nova-manage cell_v2 create_cell --name=cell1 --verbose" nova

Populate the nova database:

su -s /bin/sh -c "nova-manage db sync" nova

Verify nova cell0 and cell1 are registered correctly:

# su -s /bin/sh -c "nova-manage cell_v2 list_cells" nova

Start the Compute services and configure them to start when the system boots:

# systemctl enable \
    openstack-nova-api.service \
    openstack-nova-scheduler.service \
    openstack-nova-conductor.service \
    openstack-nova-novncproxy.service
# systemctl start \
    openstack-nova-api.service \
    openstack-nova-scheduler.service \
    openstack-nova-conductor.service \
    openstack-nova-novncproxy.service

check your compute service list by:

# openstack compute service list

Install and configure Placement

• We also need to do the 1 and 2 items for the user placement.

#openstack user create --domain default --project PROJECTNAME --password-prompt placement
#openstack role add --project PROJECTNAME --user placement admin
#openstack service create --name placement \
  --description "Placement API" placement
#openstack endpoint create --region RegionOne \
  placement public http://controller:8778
#openstack endpoint create --region RegionOne \
  placement internal http://controller:8778
#openstack endpoint create --region RegionOne \
  placement admin http://controller:8778

Create Database

Use the database access client to connect to the database server as the root user:

$ mysql -u root -p
MariaDB [(none)]>create database placement;
MariaDB [(none)]>grant all privileges on placement.* to placement@'%' identified by 'PLACEMENT_DBPASS';
MariaDB [(none)]>grant all privileges on placement.* to placement@'localhost' identified by 'PLACEMENT_DBPASS';

Replace PLACEMENT_DBPASS with a suitable password.

Install and configure components

you just need config placement on the controller.

Edit the /etc/placement/placement.conf file and complete the following actions:

In the [placement_database] section, configure database access:

[placement_database]
# ...
connection = mysql+pymysql://placement:PLACEMENT_DBPASS@controller/placement

• Replace PLACEMENT_DBPASS with the password you chose for the placement database.

In the [api] and [keystone_authtoken] sections, configure Identity service access:

[api]
# ...
auth_strategy = keystone

[keystone_authtoken]
# ...
auth_url = http://controller:5000/v3
memcached_servers = controller:11211
auth_type = password
project_domain_name = Default
user_domain_name = Default
project_name = service
username = placement
password = PLACEMENT_PASS

Replace PLACEMENT_PASS with the password you chose for the placement user in the Identity service.

Comment out or remove any other options in the [keystone_authtoken] section.

The value of user_name, password, project_domain_name and user_domain_name need to be in sync with your keystone config.

Populate the placement database:

# su -s /bin/sh -c "placement-manage db sync" placement

Restart the httpd service:

# systemctl restart httpd

if you have any problem lets see placement.api.log

compute

OpenStack Compute supports many hypervisors, which might make it difficult for you to choose one.

KVM is configured as the default hypervisor for Compute.

To determine whether the svm or vmx CPU extensions are present, run this command:

grep -E 'svm|vmx' /proc/cpuinfo

To list the loaded kernel modules and verify that the kvm modules are loaded, run this command:

# lsmod | grep kvm

Install KVM

# yum install qemu-kvm libvirt virt-install

The KVM hypervisor supports the following virtual machine image formats:

• Raw
• QEMU Copy-on-write (qcow2)
• QED Qemu Enhanced Disk
• VMware virtual machine disk format (vmdk)

start kvm module in kernel by start libvirtd

# systemctl start libvirtd
# systemctl enable libvirtd

Install and configure a compute node

This section describes how to install and configure the Compute service on a compute node.The service supports several hypervisors to deploy instances or virtual machines (VMs). For simplicity, this configuration uses the Quick EMUlator (QEMU) hypervisor with the kernel-based VM (KVM) extension on compute nodes that support hardware acceleration for virtual machines.

Install and configure components

Install the packages:

# yum --enablerepo=centos-openstack-train install openstack-nova-compute

Edit the /etc/nova/nova.conf file and complete the following actions:

In the [DEFAULT] section, enable only the compute and metadata APIs:

[DEFAULT]
# ...
enabled_apis = osapi_compute,metadata

To enable KVM explicitly, add the following configuration options to the /etc/nova/nova.conf file:

compute_driver = libvirt.LibvirtDriver

[libvirt]
virt_type = kvm

vim /etc/httpd/conf.d/00-placement-api.conf

<Directory /usr/bin>
    Require all granted
  </Directory>
</VirtualHost>

restart compute node with httpd:

#systemctl restart httpd

you can see nova-compute in list

#openstack compute service list

Add the compute node to the cell database

Run the following commands on the controller node.

Discover compute hosts:

# sudo -u nova nova-manage cell_v2 list_hosts
# su -s /bin/sh -c "nova-manage cell_v2 discover_hosts --verbose" nova

Start the Compute service including its dependencies and configure them to start automatically when the system boots:

# systemctl enable libvirtd.service openstack-nova-compute.service
# systemctl start libvirtd.service openstack-nova-compute.service

— — — — — — — — — — — — — — — — — — — — — — — — — — — — — — -

The more customized your nova, the better the performance.

congratulation ! nova is ready.

next :

• we will learn about neutron

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