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What is Container Networking?

Containers have grown in popularity as a means of packaging and delivering software. Despite the fact that the underlying technology had been accessible in the Linux kernel for many years, it was not widely used until Docker came along and made it simple to use. Despite the fact that runtime isolation is one of the key benefits, containers that operate in isolation are rarely useful. To deliver a variety of valuable services, several containers must interact with one another. End-users require a means of interacting with the services offered by these containers.

Container networking is a virtualization technique that divides applications into different machines. Containers are comparable to virtual machines, but they differ in a few fundamental ways.

The container ecosystem relies heavily on networking. Connecting containers running on the same host as well as on separate hosts maybe belonging to the same cluster or pool of hosts and exposing the services provided within containers to either end-users or other systems are just a few of the primary duties.

How Does a Container Networking Work?

Each virtual machine running on a hypervisor has its own operating system, applications, and libraries, and can encapsulate persistent data, install a new operating system, use a different filesystem than the host, and employ a different kernel.

In contrast, containers are a "running instance" of an image, virtualization of an ephemeral operating system that spins up to perform some tasks before being deleted and forgotten. Because containers are ephemeral, system users run many more instances of containers than virtual machines, which require a larger address space.

A container relies on two Linux kernel features to create isolation: namespace and Cgroups. To give the container its own view of the system and isolate it from other resources, a namespace is created and unshared for each resource. Then, control groups (Cgroups) are used to monitor and restrict system resources such as CPU, memory, disk I/O, and network, among others.

Who Uses Container Networking?

Network administrators can utilize container software systems like Docker to build massive platforms for cloud-based distributed applications.

Developers and system administrators are the primary users of Docker containers. They are a dream come true for developers since they allow them to concentrate solely on writing code rather than worrying about the environment in which it will be delivered. They can also employ a large number of programs that are designed to operate on Docker containers for their own projects, giving them a significant head start.

Dockers have a smaller footprint and lower overhead than virtual machines, so system administrators can frequently reduce the number of servers necessary for application deployment. Because of their portability and ease of installation, administrators can reclaim time spent deploying individual components and virtual machines.

What are the Advantages of Container Networking?

Containers have several significant advantages:

  • Containerized Apps Can Run with Regular VMs on the Same Infrastructure: Machines can run containerized apps alongside traditional VMs on the same infrastructure, providing flexibility and speed.
  • Combine portability with security, visibility, and management: Containers' fundamental design provides for enhanced security via sandboxing, resource transparency with the host, task management, and portability of the execution environment.
  • Make the Most of Your Existing Infrastructure and Scale-Up Quickly: Use your existing SDDC to avoid costly and time-consuming infrastructure re-architecture that leads to silos - silos develop when different departments within the same firm maintain their own IT infrastructure. Because of the disparities in technical configurations in each department, this "silo effect" causes challenges when implementing organization-wide IT policies and updates. Container networking eliminates the costly and time-consuming procedure of reintegrating silos.
  • Provide a Docker-Compatible Interface for Developers: Developers who are already familiar with Docker can use a Docker-compatible interface to construct apps in containers, which can then be provisioned using the self-service management portal or UI.

What are the Disadvantages of Container Networking?

The main disadvantages of container networking are as follows:

  • Containers aren't designed to operate at bare-metal rates. Virtual machines use resources more inefficiently than containers. However, due to overlay networking, the interaction between containers and the host system, and other factors, containers still have performance overhead. You must use bare metal rather than containers if you want 100 percent bare-metal performance.
  • Container ecosystems are splintered. Although the Docker platform as a whole is open source, some container products aren't compatible with others, mainly owing to competition among the companies who support them. Red Hat's container-as-a-service platform, OpenShift, for example, only works with the Kubernetes orchestrator.
  • Persistence data storage is difficult. Unless you save it somewhere else first, all of the data inside a container is lost forever when it goes down by design. Although there are solutions to keep data persistently in Docker, such as Docker Data Volumes, this is likely a difficulty that has yet to be fully addressed.
  • Graphical applications are ineffective. Docker was created to make it easier to deploy server applications that don't need a graphical user interface. While there are several innovative ways (such as X11 video forwarding) for running a GUI software inside a container, they are at best clumsy.
  • Containers aren't appropriate for all applications. Containers are particularly useful for programs that are meant to run as a collection of discrete microservices. The sole true advantage of Docker is that it can make application distribution easier by offering a simple packaging method.

What are the Types Of Container Networks?

There are various options for connecting containers to one another and containers to hosts. The following are the most commonly used forms of container networks:

1. None

This mode does not configure any IP for the container, as the name implies. That is, the container is isolated from other containers as well as the outside network. The following are some examples of container network mode applications:

  • Containers are being tested.
  • Getting a container ready to connect to the internet.
  • Containers that don't need to communicate with the outside world.

2. Bridge

This is the most basic network mode, which allows you to connect to the host machine's other interfaces and the containers it holds. All containers are included in the bridge network by default if they are ready for usage and no network parameters have been assigned. They allow containers to communicate with one another or with the rest of the network. If particular ports have been established while building containers across the network, this bridge will be open to the outside.

  • It is a host-created private default network.
  • Containers connected to this network have an internal IP address that allows them to easily communicate with one another.
  • The Docker server (daemon) builds docker0, a virtual ethernet bridge that delivers packets between various network ports automatically.
  • When apps are run in a standalone container, these are commonly employed.

3. Host

Features of the host mode container networking are listed below:

  • It's a public network, after all.
  • It displays the services operating inside the container using the host's IP address and TCP port space.
  • It effectively eliminates network isolation between the docker host and the docker containers, which implies that a user can't run many containers on the same host if they use this network driver.

4. Underlay

Host interfaces are connected directly to containers running on the host computer using underlay networks. There are two major branches of this kind.

  • Multiple virtual network interfaces can be formed behind the host's single physical interface using MACvlan (media access control virtual local area network). Each container in MACvlan has its own IP and MAC address.
  • IPvlan (internet protocol VLAN) establishes new virtual network interfaces and assigns each one a distinct IP address. MACvlan is a related concept. The difference is that all containers on the host machine have the same MAC address.

5. Overlay

Network tunnels are used by overlays to communicate between hosts. In this approach, even if the containers are not on the same machine, they operate as if they are, allowing a network subnet to span numerous computers. Overlays are designed to address the issue of host-to-host communication. Containers on the same host that are connected to two separate container networks are unable to communicate with each other over the local bridge.

What Are the Best Container Networking?

Container platforms, in their broadest sense, are software solutions for managing containerized applications. They offer container architectures with automation, orchestration, governance, security, customization, and enterprise support.

There are several different types of container platforms:

  • Container runtime environments, such as Docker and Docker Enterprise Edition, allow you to create containers, manage container images, and execute basic operations.
  • Kubernetes and other container orchestrators allow you to manage, govern, and automate containers at scale.
  • Managed container platforms, such as Google Kubernetes Engine, provide additional services such as orchestrator management and underlying hardware resources in addition to the container engine and orchestrator.

The following is a list of common software platforms that can assist you with container deployment and management.

SolutionLicensing ModelDescription
Docker Community Edition (CE)Open Source LicenseOn the Docker Store, you can get a free open-source version of Docker. Docker CE is compatible with the following operating systems: Mac, CentOS, Debian, Fedora, Ubuntu, Windows, 10Cloud systems such as AWS and Azure. Docker CE comes with the entire Docker platform and is perfect for individuals who are just getting started with container development.
Docker Enterprise Edition (EE)Open Source LicenseThis Docker version is designed for mission-critical applications. There are three levels to it: - The Docker platform, as well as support and certification, are included at the base tier. - Advanced capabilities for image and container management, Docker Datacenter for role-based access control, and more are available in the basic tier. - All of the aforementioned are included in the advanced tier, as well as continuous vulnerability monitoring and Docker security screening.

Containers Orchestrators and Container-Based Platform as a Service

SolutionLicensing ModelDescription
KubernetesOpen sourceKubernetes (also known as K8s) is a free and open-source platform for deploying and managing containerized applications.
Red Hat OpenShiftSupport billed by Red Hat, infrastructure by partnersBased on Red Hat's open-source software, OpenShift offers a number of containerization software products. Built-in monitoring, consistent security, and centralized policy management are all features of OpenShift. It is also Kubernetes compatible.
VMware Tanzu Application ServiceLicenseVMware Tanzu has a number of solutions that help you build, run, and manage Kubernetes-based containerized applications. Turnkey microservices operations and security, native support for native Windows and.NET, and connection with CI/CD tools are just a few of Tanzu's notable solutions.
VMware Tanzu Kubernetes GridLicenseThe VMware Tanzu Kubernetes Grid Integrated Edition is built to help you deploy Kubernetes in multi-cloud scenarios.This approach makes use of Kubernetes without the need for any additional abstraction layers or proprietary modifications. This ensures that you can use Kubernetes CLI's native version.
SUSE CaaS PlatformLicenseSUSE CaaS Platform is an enterprise-grade container management solution that streamlines the entire process. It has a lot of capabilities, including lifecycle management that is automated.

Container as a Service

SolutionLicensing ModelDescription
Azure Container Service (ACS)Pay per useAzure Container Instances offers a quick and easy way to run containers on Azure. There's no need to worry about managing virtual machines or implementing higher-level services.
Amazon Elastic Container Service (ECS)Pay per useAmazon Elastic Container Service (ECS) is a cloud-based service that makes use of Amazon's elastic container technology. ECS handles containers and allows you to run apps in the AWS cloud without having to set up an environment for the code.
Amazon Elastic Kubernetes Services (EKS)Pay per useCloud-based container management is provided by Amazon Elastic Container Service for Kubernetes (EKS). Kubernetes and EKS are natively integrated.
Amazon FargatePay per useAmazon Fargate allows you to use Amazon Web Services (AWS) to run containers without having to worry about the underlying infrastructure.
Azure Kubernetes Service (AKS)Pay per useThe Azure Kubernetes Service (AKS) is a managed container orchestration service. It's built on Kubernetes and runs on Microsoft's Azure cloud.
Google Kubernetes Engine (GKE)Pay per useGKE (Google Kubernetes Engine) is an open source orchestration and management solution based on Kubernetes.
RancherPay per useRancher is a software stack that allows you to create containerized apps. Rancher is a set of tools that may be used to solve a variety of Kubernetes problems.

Are Container Networking and Docker Networking the Same?

Networking is about process-to-process communication, and Docker's networking is no different. The primary purpose of Docker networking is to establish communication between Docker containers and the outside world via the Docker daemon's host machine.

Container networking is an emerging application sandboxing mechanism used in home desktops and web-scale enterprise networking solutions. A full-featured Linux environment with its own users, file system, processes, and network stack is isolated from the host and all other containers within the container. All applications within the container may only access or modify files or resources that are contained within the container.

Docker enables the packaging and execution of an application in a container, a loosely isolated environment. The needs for applications and the networking infrastructure are two distinct and occasionally antagonistic forces. Docker networking, also known as the Container Network Model or CNM, lies between applications and the network. CNM is responsible for brokering connectivity for your Docker containers, as well as abstracting the diversity and complexity that come with networking.