OpenStack Neutron is an open-source networking service that provides networking capabilities as a service for cloud computing platforms built on the OpenStack framework. It is a fundamental component of the OpenStack Networking project and plays a crucial role in creating and managing network resources within an OpenStack environment.
Neutron offers a flexible and scalable solution for managing network connectivity and addressing requirements of cloud deployments. It enables users to create and manage networks, subnets, routers, and other networking components through a set of APIs and user interfaces.
Key Features of OpenStack Neutron:
- Network Abstraction: Neutron abstracts the underlying physical network infrastructure, allowing users to define and manage virtual networks independently. This abstraction enables the creation of multiple networks with different topologies and configurations within the same physical infrastructure.
- Virtual Networking: Neutron provides virtual networking capabilities, allowing users to create virtual routers, switches, and firewalls within their OpenStack environment. These virtual networking components can be dynamically configured and connected to provide connectivity to instances and external networks.
- Network Plugins: Neutron supports a plugin architecture that allows for the integration of various networking technologies and services. Plugins provide drivers and agents to implement specific networking functionality, such as VLAN tagging, VXLAN overlays, software-defined networking (SDN), and more.
- Multi-Tenancy: Neutron provides multi-tenancy support, enabling the isolation of network resources and policies between different tenants or projects within an OpenStack deployment. Tenants can create and manage their own networks, subnets, and routers while maintaining logical separation from other tenants.
- Security Groups: Neutron incorporates security groups, which act as virtual firewalls to control inbound and outbound traffic to instances. Security groups define a set of rules that determine which network traffic is allowed or blocked, providing a basic level of security for instances.
- Load Balancing: Neutron includes support for load balancing as a service (LBaaS), allowing users to distribute incoming network traffic across multiple instances to improve performance and availability. Load balancers can be configured and managed through Neutron’s APIs and user interfaces.
- Floating IPs: Neutron enables the allocation and association of floating IPs with instances. Floating IPs provide a publicly accessible IP address that can be used to access instances from external networks. Neutron handles the routing and network address translation (NAT) required to make instances reachable from outside the cloud environment.
- Integration with other OpenStack Services: Neutron integrates with other OpenStack services, such as Nova (compute), Cinder (block storage), and Keystone (identity service). This integration allows for seamless communication and coordination between different components of an OpenStack deployment.
Key components of the Neutron service include:
- Neutron Server: The Neutron server is the core component responsible for handling API requests and coordinating network operations. It interacts with other services and plugins to perform network provisioning and configuration tasks.
- Plugins: Neutron supports a pluggable architecture that allows for the integration of various networking technologies and vendors. Plugins provide the implementation of network services, such as virtual LANs (VLANs), overlay networks (VXLAN, GRE), software-defined networking (SDN), and more. Different plugins can be used to meet specific networking requirements.
- Agents: Neutron agents run on compute nodes and network nodes to perform network-related tasks. For example, the L2 agent manages layer 2 networking features, such as bridging and switching, while the L3 agent handles layer 3 routing and NAT (Network Address Translation). Other agents include DHCP agent, metadata agent, VPN agent, etc.
- Networking Services: Neutron offers various networking services that can be enabled through plugins. Some of the common services include DHCP (Dynamic Host Configuration Protocol) for automatic IP address allocation, routing between virtual networks using a router service, load balancing as a service (LBaaS) for distributing traffic, firewall as a service (FWaaS) for network security, and virtual private network (VPN) services.
- Extensions: Neutron provides a mechanism for extending its functionality through extensions. Extensions allow for the addition of new features and services beyond the core Neutron functionality. Examples of extensions include quality of service (QoS) support, port security, and provider network extensions.
When a user requests network-related operations, such as creating a network or attaching a virtual interface to a network, they interact with the Neutron server API. The server then delegates the specific tasks to the appropriate plugin and agent, which work together to configure the networking infrastructure accordingly.
Overall, Neutron plays a crucial role in enabling network connectivity and managing the networking aspects of an OpenStack cloud. It provides a flexible and scalable solution for virtualized network management, allowing users to create, configure, and control virtual networks to meet their specific requirements.