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Openstack Neutron Security Groups

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OpenStack Neutron Security Groups

OpenStack, an open-source cloud computing platform, offers a wide range of features and functionalities. Among these, Neutron Security Groups play a vital role in ensuring the security and integrity of the cloud environment. In this blog post, we will delve into the world of OpenStack Neutron Security Groups, exploring their significance, key features, and best practices.

Neutron Security Groups serve as virtual firewalls for instances within an OpenStack environment. They control inbound and outbound traffic, allowing administrators to define and enforce security rules. By grouping instances and applying specific rules, Neutron Security Groups provide a granular level of security to the cloud infrastructure.

Neutron Security Groups offer a variety of features to enhance the security of your OpenStack environment. These include:

1. Rule-Based Filtering: Administrators can define rules based on protocols, ports, and IP addresses to allow or deny traffic flow.

2. Port-Level Security: Each instance can be assigned to one or more security groups, ensuring that only authorized traffic reaches the desired ports.

3. Dynamic Firewalling: Neutron Security Groups support the dynamic addition or removal of rules, allowing for flexibility and adaptability.

1. Default Deny: Start with a default deny rule and only allow necessary traffic to minimize potential security risks.

2. Granular Rule Management: Avoid creating overly permissive rules and instead define specific rules that align with your security requirements.

3. Regular Auditing: Periodically review and audit your Neutron Security Group rules to ensure they are up to date and aligned with your organization's security policies.

Neutron Security Groups can be seamlessly integrated with other OpenStack components to enhance overall security. Integration with Identity and Access Management (Keystone) allows for fine-grained access control, while integration with the OpenStack Networking service (Neutron) ensures efficient traffic management.

OpenStack Neutron Security Groups are a crucial component of any OpenStack deployment, providing a robust security framework for cloud environments. By understanding their significance, leveraging key features, and implementing best practices, organizations can strengthen their overall security posture and protect their valuable assets.

Matt Conran

Highlights: OpenStack Neutron Security Groups

What is OpenStack Neutron?

OpenStack Neutron is a networking service that provides on-demand network connectivity for cloud-based applications and services. It acts as a virtual network infrastructure-as-a-service (IaaS) platform, allowing users to create and manage networks, routers, subnets, and more. By abstracting the underlying network infrastructure, Neutron provides flexibility and agility in managing network resources within an OpenStack cloud environment.

OpenStack Neutron offers a wide range of features that empower users to build and manage complex network topologies. Some of the key features include:

1. Network Abstraction: Neutron allows users to create and manage virtual networks, enabling multi-tenancy and isolation between different projects or tenants.

2. Routing and Load Balancing: Neutron provides routing functionalities, allowing traffic to flow between different networks. It also supports load balancing services, distributing traffic across multiple instances for improved performance and reliability.

3. Security Groups: With Neutron, users can define security groups that act as virtual firewalls, controlling inbound and outbound traffic for instances. This enhances the security posture of cloud-based applications.

Neutron Security Groups

Neutron Security Groups serve as virtual firewalls, controlling inbound and outbound traffic to instances within an OpenStack cloud environment. They allow administrators to define and manage firewall rules, thereby enhancing the overall security posture of the network. By grouping instances with similar security requirements, Neutron Security Groups simplify the management of network access policies.

To configure Neutron Security Groups, start by creating a security group and defining its rules. These rules can specify protocols, ports, and IP ranges for both inbound and outbound traffic. By carefully crafting these rules, administrators can enforce granular security policies and restrict access to specific resources or services.

Once Neutron Security Groups are configured, they can be easily applied to instances within the OpenStack cloud. By associating instances with specific security groups, administrators can ensure that only authorized traffic is allowed to reach them. This provides an additional layer of protection against potential threats and unauthorized access attempts.

Neutron Security Groups offer advanced features that further enhance network security. These include the ability to define security group rules based on source and destination IP addresses, as well as the option to apply security groups at the port level. Additionally, Neutron Security Groups support the use of security group logging and can integrate with other OpenStack networking services for seamless security management.

To maximize the effectiveness of Neutron Security Groups, it is crucial to follow certain best practices. Firstly, adopting a least-privilege approach is recommended, ensuring that only necessary ports and protocols are allowed. Regularly reviewing and updating the security rules is also vital to maintain an up-to-date and secure environment. Additionally, leveraging security groups in conjunction with other OpenStack security features, such as firewalls and intrusion detection systems, can provide a multi-layered defense strategy.

Virtual Networks

A monolithic plugin configured the virtual network in the early days of OpenStack Neutron (formerly known as Quantum). As a result, virtual networks could not be created using gear from multiple vendors. Even when single network vendor devices were used, virtual switches or virtual network types could not be selected. Prior to the Havana release, the Linux bridge and OpenvSwitch plugins could not be used simultaneously. As a result of the creation of the ML2 plugin, this limitation has been addressed

**Open vSwitch & Linux Bridge**

Both OVS and Linux bridge-based virtual switch configurations are supported by ML2 plugins. For network segmentation, it also supports VLANs, VXLANs, and GRE tunnels. In addition to writing drivers, it allows you to implement new types of networks. ML2 drivers fall into two categories: type drivers and mechanism drivers. The type drivers implement the network isolation types VLAN, VXLAN, and GRE. Mechanism drivers implement mechanisms for orchestrating physical or virtual switches:

With OpenStack, virtual networks are protected by network security.A virtual network’s security policies can be self-serviced, just like other network services.Using security groups, firewalls provide security services at the network boundary or at the port level.

Incoming and outgoing traffic are subject to security rules based on match conditions, which include:

  • Source and destination addresses should be subject to security policies
  • Source and destination ports of network flows
  • Traffic direction, egress/ingress

Security groups

Network access rules can be configured at the port level with Neutron security groups. Tenants can set access policies for resources within the virtual network using security groups. IPtables uses security groups to filter traffic.

Network-as-a-Service

The power of open-source cloud environments is driven by Liberty OpenStack and the Neutron networks forming network-as-a-service. OpenStack can now be used with many advanced technologies – Kubernetes network namespace, Clustering, and Docker Container Networking. By default, Neutron handles all the networking aspects for OpenStack cloud deployments and allows the creation of network objects such as routers, subnets, and ports.

For example, Neutron creates three subnets and defines the conditions for tier interaction with a standard multi-tier application with a front, middle, and backend tier. The filtering is done centrally or distributed with tenant-level firewall OpenStack security groups.

OpenStack is Modular

OpenStack is very modular, which allows it to be enhanced by commercial and open-source network technologies. The plugin architecture allows different vendors to strengthen networking and security with advanced routers, switches, and SDN controllers. Every OpenStack component manages a resource made available and virtualized to the user as a consumable service, creating a network or permitting traffic with ingress/egress rule chains. Everything is done in software – a powerful abstraction for cloud environments.

For pre-information, you may find the following helpful

  1. OpenStack Architecture
  2. Application Aware Networking

OpenStack Neutron Security Groups

Security Groups

Security groups are essential for maintaining access to instances. They permit users to create inbound and outbound rules that restrict traffic to and from models based on specific addresses, ports, protocols, and even other security groups.

Neutron creates default security groups for every project, allowing all outbound communication and restricting inbound communication to instances in the same default security group. Following security groups are locked down even further, allowing only outbound communication and not allowing any inbound traffic at all unless modified by the user.

Benefits of OpenStack Neutron Security Groups:

1. Granular Control: With OpenStack Neutron Security Groups, administrators can define specific rules to control traffic flow at the instance level. This granular control enables the implementation of stricter security measures, ensuring that only authorized traffic is allowed.

2. Enhanced Security: By utilizing OpenStack Neutron Security Groups, organizations can strengthen the security posture of their cloud environments. Security Groups help mitigate risks by preventing unauthorized access, reducing the surface area for potential attacks, and minimizing the impact of security breaches.

3. Simplified Management: OpenStack Neutron Security Groups offer a centralized approach to managing network security. Administrators can define and manage security rules across multiple instances, making it easier to enforce consistent security policies throughout the cloud infrastructure.

4. Dynamic Adaptability: OpenStack Neutron Security Groups allow dynamic adaptation to changing network requirements. As instances are created or terminated, security rules can be automatically applied or removed, ensuring that security policies remain up-to-date and aligned with the evolving infrastructure.

Implementation Example:

To illustrate the practical implementation of OpenStack Neutron Security Groups, let’s consider a scenario where an organization wants to deploy a multi-tier web application in its OpenStack cloud. They can create separate security groups for each tier, such as web servers, application servers, and database servers, with specific access rules for each group. This segregation ensures that traffic is restricted to only the necessary ports and protocols, reducing the attack surface and enhancing overall security.

OpenStack Neutron Security Groups: The Components

Control, Network, and Compute

The OpenStack architecture for network-as-a-service Neutron-based clouds is divided into Control, Network, and Compute components. At a very high level, the control tier runs the Application Programming Interfaces (API), compute is the actual hypervisor with various agents, and the network component provides network service control.

All these components use a database and message bus. Examples of databases include MySQL, PostgreSQL, and MariaDB; for message buses, we have RabbitMQ and Qpid. The default plugins are Modular Layer 2 (ML2) and Open vSwitch. 

Openstack Neutron Security Groups

Ports, Networks, and Subnets

Neutrons’ network-as-a-service core and the base for the API are elementary. It consists of Ports, Networks, and Subnets. Ports hold the IP and MAC address and define how a VM connects to the network. They are an abstraction for VM connectivity.

A network is a Layer 2 broadcast domain represented as an external network (reachable from the Internet), provider network (mapped to an existing network), and tenant network, created by cloud users and isolated from other tenant networks. Layer 3 routers connect networks; subnets are the subnet spaces attached to networks. 

OpenStack Neutron: Components

OpenStack networking with Neutron provides an API to create various network objects. This powerful abstraction allows the creation of networks in software and the ability to attach multiple subnets to a single network. The Neutron Network is isolated or connected with Layer 3 routers for inter-network connectivity.

Neutron employs floating IP, best understood as a 1:1 NAT translation. The term “floating” comes from the fact that it can be modified on the fly between instances.

It may seem that floating IPs are assigned to instances, but they are actually assigned to ports. Everything gets assigned to ports—fixed IPs, Security Groups, and MAC addresses. SNAT (source NAT) or DNAT (destination NAT) enables inbound and outbound traffic to and from tenants. DNAT modifies the destination’s IP address in the IP packet header, and SNAT modifies the sender’s IP address in IP packets. 

Open vSwitch and the Linux bridge

Neutrons can be integrated for switching functionality with Open vSwitch and Linux bridge. By default, it integrates with the ML2 plugin and Open vSwitch. Open vSwitch and Linux bridges are virtual switches orchestrating the network infrastructure.

For enhanced networking, the virtual switch can be controlled outside Neutron by third-party network products and SDN controllers via plugins. The Open vSwitch may also be replaced or used in parallel. Recently, many enhancements have been made to classic forwarding with Open vSwitch and Linux Bridge.

We now have numerous high availability options with L3 High Availability & VRRP and Distributed Virtual Routing (DVR) feature. DVR essentially moves to route from the Layer 3 agent to compute nodes. However, it only works with tunnels and L2pop enabled, requiring the compute nodes to have external network connectivity.

For production environments, these HA features are a welcomed update. The following shows three bridges created in Open vSwitch – br-ex, br-ens3, and br-int. The br-int is the main integration bridge; all others connect via particular patch ports.

Openstack Neutron Security Groups

Network-as-a-service and agents

Neutron has several parts backed by a relationship database. The Neutron server is the API, and the RPC service talks to the agents (L2 agent, L3 agent, DHCP agent, etc.) via the message queue. The Layer 2 agent runs on the compute and communicates with the Neutron server with RPC. Some deployments don’t have an L2 agent, for example, if you are using an SDN controller.

Also, if you deploy the Linux bridge instead of the Open vSwitch, you don’t have the Open vSwitch agent; instead, use the standard Linux Bridge utilities. The Layer 3 agent runs on the Neutron network node and uses Linux namespaces to implement multiple copies of the IP stack. It also runs the metadata agent and supports static routing. 

Linux Namespaces

An integral part of Neutron networking is the Linux namespace for object isolation. Namespaces enable multi-tenancy and allow overlapping IP address assignment for tenants – an essential requirement for many cloud environments. Every network and network service a user creates is a namespace.

For example, the qdhcp namespace represents the DHCP services, qrouter namespace represents the router namespace and the qlbaas represents the load balance service based on HAProxy. The qrouter namespaces provide routing amongst networks – north-south and east-west traffic. It also performs SNAT and DNAT in classic non-DVR scenarios. For certain cases with DVR, the snat namespaces perform SNAT for north-south network traffic.

 OpenStack Neutron Security Groups

OpenStack has the concept of OpenStack Neutron Security Groups. They are a tenant-level firewall enabling Neutron to provide distributed security filtering. Due to the limitations of Open vSwitch and iptables, the Linux bridge controls the security groups. Neutron security groups are not directly added to the Integration bridge. Instead, they are implemented on the Linux bridge that connects to the integrated bridge.

The reliance on the Linux bridge stems from Neutron’s inability to place iptable rules on tap interfaces connected to the Open vSwitch. Once a Security Group has been applied to the Neutron port, the rules are translated into iptable rules, which are then applied to the node hosting the respective instance.

Neutron also can protect instances with perimeter firewalls, known as Firewall-as-a-service.

Firewall rules implemented with perimeter firewalls utilizing iptables within a Neutron routers namespace instead of configuring on every compute host. The following diagram displays ingress and egress rules for the default security group. Tenants that don’t have a security group are placed in the default security group.

Openstack Neutron Security Groups

OpenStack Neutron Security Groups offer a robust solution for managing network security in OpenStack-based cloud environments. By providing granular control, enhanced security, simplified management, and dynamic adaptability, they contribute significantly to safeguarding cloud deployments. As organizations continue to embrace the benefits of OpenStack, leveraging the power of Neutron Security Groups becomes paramount in building secure and resilient cloud infrastructures.

Summary: OpenStack Neutron Security Groups

OpenStack, a powerful cloud computing platform, offers a range of networking features to manage virtualized environments efficiently. One such feature is OpenStack Neutron, which enables the creation and management of virtual networks. In this blog post, we will delve into the realm of OpenStack Neutron security groups, understanding their significance, and exploring their configuration and best practices.

Understanding Neutron Security Groups

Neutron security groups act as virtual firewalls, allowing administrators to define and enforce network traffic rules for instances within a particular project. These security groups provide an added layer of protection by controlling inbound and outbound traffic, ensuring network security and isolation.

Configuring Neutron Security Groups

Configuring Neutron security groups requires a systematic approach. Firstly, you need to define the necessary security group rules, specifying protocols, ports, and IP ranges. Secondly, associate the security group rules with specific instances or ports to control the traffic flow. Finally, ensure that the security group is applied correctly to the virtual network or subnet to enforce the desired restrictions.

Best Practices for Neutron Security Groups

To maximize the effectiveness of Neutron security groups, consider the following best practices:

1. Implement the Principle of Least Privilege: Only allow necessary inbound and outbound traffic, minimizing potential attack vectors.

2. Regularly Review and Update Rules: As network requirements evolve, periodically review and update the security group rules to align with changing needs.

3. Combine with Other Security Measures: Neutron security groups should complement other security measures such as network access control lists (ACLs) and virtual private networks (VPNs) for a comprehensive defense strategy.

4. Logging and Monitoring: Enable logging and monitoring of security group activities to detect and respond to any suspicious network behavior effectively.

Conclusion:

OpenStack Neutron security groups are a vital component in ensuring the safety and integrity of your cloud network. By understanding their purpose, configuring them correctly, and following best practices, you can establish robust network security within your OpenStack environment.

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Neutron Networks

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Neutron Networks

In today's digital age, connectivity has become essential to our personal and professional lives. As the demand for seamless and reliable network connections grows, businesses seek innovative solutions to meet their networking needs. One such solution that has gained significant attention is Neutron Networks. In this blog post, we will delve into Neutron Networks, exploring its features, benefits, and how it is revolutionizing connectivity.

Neutron Networks is an open-source networking project within the OpenStack platform. It acts as a networking-as-a-service (NaaS) solution, providing a programmable interface for creating and managing network resources. Unlike traditional networking methods, Neutron Networks offers a flexible framework that allows users to define and control their network topology, enabling greater customization and scalability.

Neutron networks serve as the backbone of OpenStack's networking service, providing a way to create and manage virtual networks for cloud instances. By abstracting the complexities of network configuration and provisioning, neutron networks offer a flexible and scalable solution for cloud deployments.

The architecture of neutron networks consists of various components working together to enable network connectivity. These include the neutron server, neutron agents, and the neutron plugin. The server acts as the central control point, while agents handle network operations on compute nodes. The plugin interfaces with underlying networking technologies, such as VLAN, VXLAN, or SDN controllers, allowing for diverse network configurations.

Neutron networks comprise several key components that contribute to their functionality. These include subnets, routers, security groups, and ports. Subnets define IP address ranges, routers enable inter-subnet communication, security groups provide firewall rules, and ports connect instances to the networks.

Neutron networks bring numerous advantages to cloud computing environments. Firstly, they offer network isolation, allowing different projects or tenants to have their own virtual networks. Additionally, neutron networks enable dynamic scaling and seamless migration of instances between hosts. They also support advanced networking features like load balancing and virtual private networks (VPNs), enhancing the capabilities of cloud deployments.

Neutron networks are a vital component of OpenStack, providing a robust and flexible solution for network management in cloud environments. Understanding their architecture and key components empowers cloud administrators to create and manage virtual networks effectively. With their ability to abstract the complexities of networking, neutron networks contribute to the scalability, security, and overall performance of cloud computing.

Matt Conran

Highlights: Neutron Networks

Neutron Networking

A– As part of OpenStack, Neutron networking is a software-defined networking (SDN) solution that enables virtual networks and connectivity in cloud environments. It acts as a networking-as-a-service (NaaS) component, providing a flexible and scalable approach to network management.

B– Within the Neutron framework, several essential components facilitate network connectivity. These include the neutron server, agents, plugins, and drivers. Each component ensures seamless communication between virtual machines (VMs) and the physical network infrastructure.

C– Neutron is composed of several key components that work in tandem to deliver a comprehensive networking solution. The Neutron server, for instance, acts as the central hub that orchestrates all networking requests and communicates with various agents deployed across the cloud infrastructure.

D– These agents, like the L3 agent and DHCP agent, are responsible for routing and addressing, ensuring that each instance within the cloud has the necessary network configuration. Additionally, Neutron utilizes plugins to support different networking technologies, offering flexibility and adaptability to its users.

**Various Networking Models**

Neutron supports various networking models, including flat networking, VLAN segmentation, and overlay networks. Each model offers distinct advantages and caters to different use cases. Understanding these models and their benefits is essential for network administrators and architects.

**Neutron Advanced Features**

Neutron networking offers advanced features such as security groups, load balancing, and virtual private networks (VPNs). These features enhance network security, performance, and isolation, enabling efficient and reliable communication across virtual machines.

Key Features and Functionality

Neutron Network offers a wide range of features that empower users to have fine-grained control over their network infrastructure. Some of its notable features include:

1. Network Abstraction: Neutron Network provides a high-level abstraction layer that simplifies the management of complex network topologies. It enables users to create and manage networks, subnets, and ports effortlessly.

2. Virtual Router: With Neutron Network, users can create virtual routers that can connect multiple networks, providing seamless connectivity and routing capabilities.

3. Security Groups: Neutron Network allows the creation of security groups to enforce network traffic filtering and access control policies. This enhances the overall security posture of the network infrastructure.

OpenStack Networking

A – ) An OpenStack-based cloud can manage networks and IP addresses with OpenStack Networking, a pluggable, scalable, API-driven system. Administrators and users can use the OpenStack Networking component to maximize the value and utilization of existing data center resources.

B – ) In addition to Nova’s compute service and Glance’s image service, Keystone’s identity service, Cinder’s block storage, and Horizon’s dashboard, Neutron’s networking service can be installed independently of other OpenStack services. Multiple hosts can provide resiliency and redundancy, or a single host can be configured to provide the networking services.

C – ) In OpenStack Networking, users can access a programmable interface, or API, that passes requests to the configured network plugins for further processing. Cloud operators can leverage different networking technologies to enhance and power cloud connectivity.

OpenStack Networking

Through IP forwarding, iptables, and network namespaces, OpenStack Networking provides routing and NAT capabilities. Network namespaces contain sockets, bound ports, and interfaces. Iptables processes and routing tables are separate components of each network namespace responsible for filtering and translating network addresses.

Using network namespaces to separate networks eliminates the risk of overlapping subnets between tenants’ networks. By configuring a router in Neutron, instances can communicate with outside networks. As well as Firewall as a Service and Virtual Private Network as a Service, router namespaces are also used by advanced networking services.

Data Center Expansion

Data centers today have more devices than ever before. Virtual machines and virtual network appliances have replaced Servers, routers, storage systems, and security appliances that once occupied rows of data center space. These devices place a great deal of strain on traditional network management systems due to their scalability and automation requirements. Infrastructure provisioning will be faster and more flexible with OpenStack.

An OpenStack-based cloud can manage its networks with OpenStack Networking, which is pluggable, scaleable, and API-driven. As with other core OpenStack components, administrators and users can use OpenStack Networking to maximize data center utilization.

It combines Compute (Nova), Image (Glance), Identity (Keystone), Block (Cinder), Object (Swift), and Dashboard (Horizon) into a complete cloud solution.

Openstack services

OpenStack Networking API

– Users can access OpenStack Networking’s API by requesting additional processing from configured network plugins. By defining network connectivity, cloud operators can enhance and power their clouds.

– It is possible to deploy OpenStack Networking services across multiple hosts or on a single node to provide resiliency and redundancy. Like many other OpenStack services, Neutron requires access to a database to store network configurations.

– A database containing the logical network configuration is connected to the Neutron server. Neutron servers receive API requests from users and services, and agents respond via message queues. Most network agents are dispersed across controllers and compute nodes and perform their duties there.

Neutron Server

The Role of OpenStack Networking

OpenStack and neutron networks offer virtual networking services and connectivity to and from Instances. They play a significant role in the adoption of OpenFlow and SDN. The Neutron API manages the configuration of individual networks, subnets, and ports. It enhanced the original Nova network implementation and introduced support for third-party plugins, such as Open vSwitch (OVS) and Linux bridge.

OVS and LinuxBridge provide Layer 2 connectivity with VLANs or Overlay encapsulation technologies, such as GRE or VXLAN. Neutrons are pretty basic, but their capability is gaining momentum with each distribution release with the ability to include an OpenStack neutron load balancer.

Use Cases and Benefits:

Neutron Network finds applications in various scenarios, making it a versatile networking solution. Here are a few notable use cases:

1. Multi-Tenant Environments: Neutron Network enables service providers to offer segregated network environments to different tenants, ensuring isolation and security between them.

2. Software-Defined Networking (SDN): Neutron Network plays a crucial role in implementing SDN concepts by providing programmable and flexible network infrastructure.

3. Hybrid Cloud Deployments: With Neutron Network, organizations can seamlessly integrate public and private cloud environments, enabling hybrid cloud deployments with ease.

You may find the following helpful post for pre-information:

  1. OpenStack Neutron Security Groups
  2. Neutron Network
  3. OpenStack Architecture

Neutron Networks

OpenStack Networking

OpenStack Networking is a pluggable, API-driven approach to control networks in OpenStack. OpenStack Networking exposes a programmable application interface (API) to users and passes requests to the configured network plugins for additional processing. A virtual switch is a software application that connects virtual machines to virtual networks. The virtual switch operated at the data link layer of the OSI model, Layer 2. A considerable benefit to Neutron is that it supports multiple virtual switching platforms, including Linux bridges provided by the bridge kernel module and Open vSwitch.

  • A key point: Ansible and OpenStack

Ansible architecture offers excellent flexibility and can be used ways to leverage Ansible modules and playbook structures to automate frequent operations with OpenStack. With Ansible, you have a module to manage every layer of the OpenStack architecture. At the time of this writing, Ansible 2.2 includes modules to call the following APIs

  • Keystone: users, groups, roles, projects
  • Nova: servers, keypairs, security groups, flavors
  • Neutron: ports, network, subnets, routers, floating IPs
  • Ironic: nodes, introspection
  • Swift Objects
  • Cinder volumes
  • Glance images

Neutron Networks

Neutron networks support a wide range of networks. Including Flat, Local, VLAN, and VXLAN/GRE-based networks. Local networks are isolated and local to the Compute node. In a FLat network, there is no VLAN tagging. VLAN-capable networks implement 802.1Q tagging; segmentation is based on VLAN tags. Similar to the physical world, hosts in VLANs are considered to be in the same broadcast domain, and inter-VLAN communication must pass a Layer 3 device.

GRE and VXLAN encapsulation technologies create the concept known as overlay networking. Network Overlays interconnect layer 2 segments over an Underlay network, commonly an IP fabric but could also be represented as a Layer 2 fabric. Their use case derives from multi-tenancy requirements and the scale limitations of VLAN-based networks.

The virtual switches

Open vSwitch and Linux Bridge

Open vSwitch and Linux Bridge plugins are monolithic and cannot be used simultaneously. A new plugin, introduced in Havana, called Modular Layer 2 ( ML2 ), allows the use of multiple Layer 2 plugins simultaneously. It works with existing OVS and LinuxBridge agents and is intended to replace the associated plugins.

OpenStack foundations are pretty flexible. OVS and other vendor appliances could be used parallel to manage virtual networks in an OpenStack Neutron deployment. Plugins can replace OVS with a physically managed switch to handle the virtual networks. 

Open vSwitch

The OVS bridge is a popular software-based switch orchestrating the underlying virtualized networking infrastructure. It comprises a kernel module, a vSwitch daemon, and a database server. The kernel module is the data plane, similar to an ASIC on a physical switch. The vSwitch daemon is a Linux process creating controls so the kernel can forward traffic.

The database server is the Open vSwitch Database Server ( OVSDB) and is local on every host. OVS consists of 4 distinct elements, – Tap devices, Linux bridges, Virtual Ethernet cables, OVS bridges, and OVS patch ports. Virtual Ethernet cables, known as veth mimic network patch cords.

They connect to other bridges and namespaces (namespaces discussed later). An OVS bridge is a virtualized switch. It behaves similarly to a physical switch and maintains MAC addresses.

openstack networking

**OpenStack networking deployment details**

A few OpenStack deployment methods exist, such as Maas, Mirantis Fuel, Kickstack, and Packstack. They all have their advantages and disadvantages. Packstack suits small deployments, Proof of Concepts, and other test environments. It’s a simple Puppet-based installer. It uses SSH to connect to the nodes and invokes a puppet run to install OpenStack.

Additional configurations can be passed to Packstack via an answer file. As part of the Packstack run, a file called keystonerc_admin is created. Keystone is the identity management component of OpenStack. Each element in OpenStack registers with Keystone. It’s easier to source the file than those values in the source file, which are automatically placed in the shell environment.

Cat this file to see its content and get the login credentials. You will need this information to authenticate and interact with OpenStack.

openstack neutron load balancer

OpenStack lbaas Architecture

Neutron networks 

OpenStack is a multi-tenant platform; each tenant can have multiple private networks and network services isolated through network namespaces. Network namespaces allow tenants to have overlapping networks with other tenants. Consider a namespace for an enhanced VRF instance connected to one or more virtual switches. Neutron uses a “qrouter,” “glbaas,” and “qdhcp” namespaces.

Regardless of the network plugins installed, you need to install the neutron-server service at minimum. This service will expose the Neutron API for external administration. By default, it is configured to listen to API calls on ALL addresses. You can change this in the Neutron.conf file by editing the bind_host—0.0.0.0.

  • “Neutron configuration file is found at /etc/neutron/neutron.conf”

OpenStack networking provides extensions that allow the creation of virtual routers and virtual load balancers with an OpenStack neutron load balancer. Virtual routers are created with the neutron-l3-agent. They perform Layer 3 forwarding and NAT.

A router default performs Source NAT on traffic from an instance destined to an external service. Source NAT modifies the packet source appearing to upstream devices as if it came from the router’s external interface. When users want direct inbound access to an instance, Neutron uses what is known as a Floating IP address. It is similar to the analogy of Static NAT; one-to-one mapping of an external to an internal address. 

  • “Neutron stores its L3 configuration in the l3_agent.ini files.”

The following screenshot displays that the L3 agent must first be associated with an interface driver before you can start it. The interface driver must correspond to the chosen network plugin, for example, LinuxBridge or OVS. The “crudini“ commands set this.openstack lbaas architecture

OpenStack neutron load balancer

The OpenStack LBaaS architecture consists of the neutron-lbaas-agent and leverages the open-source HAProxy to load balance traffic destined to VIPs. HAProxy is a free, open-source load balancer. LBaaS supports third-party drivers, which will be discussed in later posts.

Load Balancing as a service enables tenants to scale their applications programmatically through Neutron API. It supports basic load-balancing algorithms and monitoring capabilities.

The OpenStack lbaas architecture load balancing algorithms are restricted to round-robin, least connections, and source IP. It can do basic TCP connect tests for monitoring and complete Layer 7 tests that support HTTP status codes.

HAProxy installation

As far as I’m aware, it doesn’t support SSL offloading. The HAProxy driver is installed in one ARM mode, which uses the same interface for ingress and egress traffic. It is not the default gateway for instances, so it relies on Source NAT for proper return traffic forwarding. Neutron stores its configuration in the lbaas_agent.ini files.

Like the l3 agent, it must associate with an interface driver before starting it – “crudini –set /etc/neutron/lbaas_agent.ini DEFAULT interface_driver neutron.agent.linux.interface.OVSInterfaceDriver”. Both agents use network namespaces for isolated forwarding and load-balancing contexts.

Neutron Networks has emerged as a game-changer in the networking world, offering organizations the flexibility, scalability, and security they need in today’s digital landscape. With its innovative features and benefits, Neutron Networks is paving the way for a new era of connectivity, empowering businesses to unlock the full potential of their network infrastructure. As the demand for reliable and efficient networking solutions continues to grow, Neutron Networks is well-positioned to shape the future of connectivity.

Summary: Neutron Networks

In today’s interconnected world, seamless and reliable network connectivity is necessary. Behind the scenes, a fascinating technology known as neutron networks forms the backbone of this connectivity. In this blog post, we delved into the intricacies of neutron networks, uncovering their inner workings and understanding their critical role in modern communication systems.

Understanding Neutron Networks

Neutron networks, a core component of OpenStack, manage and orchestrate network connectivity within cloud infrastructures. They provide a virtual networking service, allowing users to create and manage networks, routers, subnets, and more. By abstracting the complexity of physical network infrastructure, neutron networks offer flexibility and scalability, enabling efficient communication between virtual machines and external networks.

Components of Neutron Networks

To grasp the functioning of neutron networks, we must familiarize ourselves with their key components. These include:

1. Network: The fundamental building block of neutron networks, a network represents a virtual isolated layer 2 broadcast domain. It provides connectivity between instances and allows traffic flow within a defined scope.

2. Subnet: A subnet defines a network’s IP address range and associated configuration parameters. It plays a crucial role in assigning addresses to instances and facilitating communication.

3. Router: Routers connect different networks, enabling traffic flow. They serve as gateways, directing packets to their destinations while enforcing security policies.

Neutron Networking Models

Neutron networks offer various networking models to accommodate diverse requirements. Two popular models include:

1. Provider Network: In this model, neutron networks leverage existing physical network infrastructure. It allows users to connect virtual machines to external networks and integrate with external services seamlessly.

2. Self-Service Network: This model empowers users to create and manage their own networks within the cloud infrastructure. It provides isolation and control, making it ideal for multi-tenant environments.

Advanced Features and Capabilities

Beyond the basics, neutron networks offer a range of advanced features and capabilities that enhance network management. Some notable examples include:

1. Load Balancing: Neutron networks provide load balancing services, distributing traffic across multiple instances to optimize performance and availability.

2. Virtual Private Network (VPN): By leveraging VPN services, neutron networks enable secure and encrypted communication between networks or remote users.

Conclusion:

In conclusion, neutron networks are the invisible force behind modern connectivity, enabling seamless communication within cloud infrastructures. By abstracting the complexities of network management, they empower users to create, manage, and scale networks effortlessly. Whether connecting virtual machines or integrating with external services, neutron networks are pivotal in shaping the digital landscape. So, next time you enjoy uninterrupted online experiences, remember the underlying power of neutron networks.