How Docker Networking Works

Networking as we know it is the transportation of resources among different nodes of a network. Well, networking is not only about designing a network and connecting nodes with it and maintaining those nodes and the network. With the help of networking, we connect endpoint devices, through a network, the network is commonly called the internet.

As we know, the most basic use of networking is to share data and resources. But it also creates an environment where multiple users can work on a project, and they can store their data at a centralized location. It also helps us monitor the resources and keep track of everything. That too happens most securely as security is the biggest concern when it comes to networking.

We are living in the era of virtualization, where we do not need to move an inch, and all of our works take place digitally. As things are getting digitalized, networking is getting complicated, making it hard to administrate a network. We are now using complex networking components due to complex networking. And they are not just routers and LAN / WAN switches anymore. As we go ahead in the era of digitalization, we are getting familiar with the latest concepts of information technology. Containerization is one of those concepts of information technology, which is the latest and a complicated concept to understand, which demands hardcore networking skills as well. To implement this concept, we need software that can configure and run it. Here comes the Docker, a software that can do all of this.

What is Docker?

When it comes to containerization, there is always one name that comes up, that is Docker. As it is the software platform that introduced the concept of containerization in information technology. Well, if we talk about containerization, it is the process of packing an application with all the files it depends on like modules, libraries, and operating systems. By doing this, software becomes easily executable in any environment. It creates a complete package for an application, and we also call it a docker container that contains everything an application needs to execute and run. We can create Docker containers for specifically an environment as it is custom made. It can be a CakePHP container, a Ubuntu container, a CentOS container, or any other.

Let us take an example of a java application here. Suppose there is an application we developed to execute in an environment with the Tomcat server in it. After the development process, the application will be sent for testing the tester will have to set up a Tomcat server to run the application. After that, it will go to the production department, where we will need the same Tomcat server, which will take a lot of time and resources. What happens in a docker container is, it has the environment already in it, so there will be no need to install anything to run an application for any purpose. It will eventually save a lot of time and resources that will be very beneficial.

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Docker Networking Basics and Its Drivers

When we install the docket at first, we get three networks of docker that we configure. These are Host, None, and the bridge. The two networks that are a part of the docker stack are None and Host that are very valuable for the docker. There is a third one that is the bridge, and we can configure it as well. You can learn everything regarding the docker by taking docker training you can take it online or offline as there are options available.  A docker container can be connected to multiple networks at a time.

• Bridge

A bridge is a network that is created on the host of the docker. This network creates an IP subnet and gateway, and all the containers on this network are a part of the same subnet. All the containers here communicate through IP addressing. The bridge networks work well when we are executing an application in a standalone docker container.

• Host

When the host driver is used in a standalone container, it does not get a specific IP address. The isolation between the docker stack and docker host is removed when we use the host driver. We can run multiple web containers on a single host if we use a host driver.

• None

In the None network, a  docker-container has no link to any other network or container. It has no access or attachment to any of the external networks. When we use none, a network stack is disabled on that particular container. It only has a loopback interface with no other connections.

• Overlay

An overlay is a network driver in the docker that creates a private network that helps all the nodes communicate. It is mainly to communicate different docker containers from the same network or a different one.

• Macvlan

It is a network driver that helps to allocate a Mac address to all the containers, by which means all of the containers appear as a physical device over the network. All the traffic is then diverted towards these containers with those Mac addresses. If you want your docker-container to link with a physical network, it is the most suitable option.

How Docker Networking Works

When it comes to docker networking, there is no hard and fast rule for that. It all depends on the requirement and the application you are working for.

Let us suppose we have to store book names, and we need a web application, or we would say, we need a container for a web application, and a container for MySQL, and both of them will be linked.  There are some steps we need to follow to accomplish this goal.

• The first thing is to make sure you have Docker installed on your system. If not, install it before doing anything else.
• The next step is to initialize the Docker swarm on your system. There will be an IP of the manager node, make sure all other nodes can access the manager through that IP.
• There is an option of joining the manager node to the worker node, and if you want to do that, you need to copy the link you get when you initialize the docker swarm.
• In the next step, you need to create a docker overlay network where myoverlay is the name of the network that runs in the background.
• It is now the time to create a web app with any name and deploy it to the cluster using the network you just created. After that, make sure the application is there in the cluster.
• It is now the time to create a MySQL service and deploy it to the cluster using the network you have just created. After that, check if it’s there safely and in working condition.
• Now, check your master node for the network it is running on and get into the web app container. You can now see your web app on the master node.
• It is now the time to put in all the details about the database. After filling in the details, save this file index.php with the shortcut control + x on the keyboard.
• It is now the time to go into the MySQL container and make it the database for the web app data. After you enter the MySQL container, get access to use this container as the database for the web app. If there is no database, you need to create one and then use it as the official database for the app. It is recommended to create it in a tabular form to save data.
• After you have finished making the database available for the web app, exit the MySQL container.
• Now you can access your web application by using a browser. On the browser, you will have to enter localhost:8001/index.php, and after pressing enter your application will open. You will now enter all the details of books and enter submit queries. After pressing enter, go to the node where your MySQL container is, and you will find all the details about the books.

There you go with all the steps that are needed to work with a docker container. By following these steps, we can create a docker container for our applications and a MySQL container to use it as a database for our application.

Well, as we have discussed, how significant the docker technology is for the present and the future. As it does not only save our time but saves our resources as well, which can be an eye-catching feature for any organization. Keeping in mind the future perspective, a lot of organizations have already started providing docker training to their employees. It is still in the implementation process and will be there capturing the world very shortly. That was all from us about the docker containerization technology.