How to Configure OpenStack Network to Enable Access to OpenStack Instances?

Introduction

OpenStack is an open-source cloud computing platform that enables the creation and management of public, private, and hybrid cloud environments. The platform provides a wide range of services including computing, storage, and networking. OpenStack Networking, also known as Neutron, is a service that offers software-defined networking capabilities for OpenStack environments.

Understanding OpenStack Networking Concepts

OpenStack is an open-source cloud computing platform that allows users to create, manage, and provision cloud computing resources. One of the most critical components of OpenStack is networking. Understanding OpenStack networking concepts requires knowledge of the overall architecture and types of networks in OpenStack.

Overview of OpenStack Networking Architecture

The architecture for OpenStack networking consists of two primary components: the data plane and the control plane. The data plane is responsible for handling the actual network traffic between instances, while the control plane manages routing tables, security policies, and other network-related functions.

Types of Networks in OpenStack

Openstack has three types of networks: Provider Network, Self-Service Network, and External Network.

Provider Network

A provider network connects instances to physical networks outside of the cloud environment. This type of network typically uses VLANs or VXLANs to encapsulate traffic between instances.

Self-Service Network

A self-service network connects instances within a tenant's virtual private cloud (VPC). This type of network can be provisioned on-demand by users within a tenant's VPC without requiring administrator-level access.

External Network

An external network is used to provide connectivity from instances running on self-service networks to servers outside the cloud environment or other resources such as public IP addresses or DNS servers. Typically this type of network uses NAT or VPN gateways to bridge between internal networks and external ones.

Understanding Subnets, Routers, and Ports in OpenStack

To enable communication between instances running on different virtual machines (VMs), we need a way to segment communication into separate subnets. Subnets are logical divisions of an IP network that allow for routing between different groups of machines. Routers in OpenStack provide the ability to connect different subnets together, allowing communication between instances running on separate VMs.

Configuring Provider Network

Setting up a Physical Network Interface for the Provider Network

To achieve this, we must configure the network interfaces of all OpenStack hosts to allow communication via our chosen provider network. This requires modifying specific files and configuring various parameters for your Linux distribution.

Creating a Provider Network in OpenStack Horizon Dashboard

Once the physical network interface is configured on each host, we can create the provider network in OpenStack Horizon Dashboard. The creation of a provider network involves defining its name, subnet, IP address range, and other related properties.

• Log in to your OpenStack dashboard.

• From the main menu on the left-hand side of your screen, click on “Network” then select “Networks”.

• Click on “Create Network” at the top right corner of your screen.

• Enter your preferred name for this new provider network.

• Choose an appropriate project from the dropdown list or leave it as default if you are not sure which project you want to use this for.

• Select "Provider Network" as a type of connectivity

• Under "Physical Network", enter details about physical connectivity information that was previously configured (for example 'physnet1')

• Define Subnet and IP Address Range for this new provider

• Click on "Create" to save configuration

Defining Subnet and IP Address Range for the Provider Network

When creating or editing a provider network configuration details like Subnet & IP address range must be defined so that we can associate it with our chosen physical interface that will communicate with other instances within our cloud environment. A subnet mask is used to define the range of IP addresses available for use within a network.

Configuring Router Interface for the Provider Network

Once we have created our Provider Network, we need to ensure that it is associated with a router interface so that instances using that network can communicate with other instances or access external networks. A router allows us to establish connectivity between multiple networks by forwarding packets between them. We can configure a router interface via OpenStack Horizon Dashboard −

• Navigate to Network > Routers in your Horizon dashboard.

• Click on “Create Router”.

• Enter a name for your new router.

• Choose an appropriate project from the dropdown list or leave it as default if you are not sure which project you want to use this for.

• Select "Gateway" as connection type

• Specify External Gateway (If required)

• Under "Interfaces", click "Add Interface"

• Select your provider network you created before

• Click "Submit" and then save it By completing these steps

We have now successfully configured a provider network in OpenStack and associated it with our physical interface, allowing access to instances within our cloud environment using this new network configuration!

Configuring Self-Service Networks

Creating a Self-Service network in Openstack Horizon Dashboard

In OpenStack, self-service networks are created to provide instances with an isolated environment within the cloud infrastructure. These networks are created by users who need to set up their virtual infrastructure with unique IP addresses and routing configuration. The process of creating a self-service network in the OpenStack dashboard is relatively simple.

To create a self-service network, log in to your OpenStack Horizon Dashboard and navigate to the Networks tab from the Project menu. Select ‘Create Network’ option and fill out the required fields such as name, subnet, and other details that define the characteristics of your new self-service network.

Defining Subnet and IP Address Range for the Self-Service network

After setting up a new self-service network in OpenStack Horizon Dashboard, it’s important to define its subnet configuration. Subnets define ranges of IP addresses that can be used by instances connected to this network. By defining these subnets and IP address ranges, users can allocate resources efficiently while also ensuring that instances within these networks remain isolated from each other.

When defining subnets for your new self-service network, you must specify its starting and ending IP address range along with its corresponding netmask value.

Configuring Router Interface for the Self-Service network

Once you have a defined subnet for your new self-service network, it’s time to configure its router interface. This step is necessary if you want communication between different networks within your cloud infrastructure or if you want access to external networks such as the internet.

To configure a router interface for the newly created self-service network, navigate back to Network tab on OpenStack Horizon Dashboard and select ‘Routers’ from the left-hand menu. Next, locate the router that connects to your self-service network and click ‘Add Interface’.

Select your new self-service network from the dropdown list and complete the configuration process.

Configuring External Networks

Creating an External Network in OpenStack Horizon Dashboard

An external network in OpenStack allows instances to communicate with networks outside of the OpenStack environment. To create an external network, navigate to the "Networks" tab in the Horizon dashboard and click on the "Create Network" button. Name the network, select "External" as the provider network type, and choose a subnet for this network.

Defining Subnet and IP Address Range for the External Network

After creating an external network for your OpenStack environment, you will need to define a subnet and IP address range for this network. To do so, navigate to the "Subnets" tab in Horizon dashboard and click on "Create Subnet". Fill out information about your desired subnet including its name, IP address range, gateway IP address, DNS nameservers (if applicable), and any other relevant details.

Conclusion

Configuring OpenStack networks can seem daunting at first but by following these steps, you can create a powerful environment capable of running complex applications with ease. By utilizing provider networks, self-service networks and external networks you have created a robust infrastructure that can handle any workload necessary.