What is Docker?
Docker is an open platform that enables virtualization at the operating system level. This computer program is used for developing, shipping, and running applications. By using Docker, which allows you to keep your applications separate from your infrastructure, you can deliver your software quickly. In this way, you can manage your infrastructure in the same ways you manage your applications.
Most of the popular virtual machines like VirtualBox and VMware are quite different than Docker’s virtualization structure because they have a Hypervisor layer. Unlike these, Docker can access the host operating system via the Docker Engine and use system tools without such a layer. From this point of view, Docker consumes less system resources compared to other virtual machines.
How To Install Docker?
The installation of Docker varies according to the platform you are using. In this article, we will not go into Docker’s installation, as we are answering the frequently asked questions about Docker. But you can install Docker by choosing your own platform from the links below.
What is Docker Daemon or Docker Engine?
While answering the first question, we said that unlike other virtual machines, Docker does not have a Hypervisor layer. The equivalent of this layer in Docker is Docker Engine or Daemon. It replaces Linux Kernel’s LXC. Docker Engine is an open source containerization technology which you can use to build and containerize your applications.
Why and How To Use Docker?
Let's start by talking about a problem that almost all software developers face. The code written by the software developer runs smoothly on his own computer. When he gives the code to the tester to test it, he learns that it is not working on his computer. The reason for this is that while the developer’s computer has the necessary environment and configuration for the code to run, the tester’s machine does not have this environment. In other words, there are differences between the environments and conditions where the code is written and the one where the code is deployed.
And the solution to this problem is Docker. The code prepared and shared using Docker can thus be accessed both in the developer environment and in the standardized UAT (User Acceptance Test) and PROD (Production) environments where the code is deployed. In this way, Docker streamlines the development lifecycle. Containers are also well suited for continuous integration and continuous delivery (CI/CD) workflows.
In addition, this container-based platform of Docker permits highly portable workloads. Docker containers can run on a developer's personal laptop, physical or virtual machines in a data center, cloud providers, or in any standardized environment.