While there are many easy-to-understand articles on Qiita, I will write about Docker briefly. This is my first post, so please take a look.
What is Docker It is a platform for creating, executing, and managing container-type virtual environments.
→ What is a container-type virtual environment? First of all, the container has the same image as the box that everyone imagines to carry on a ship. As the name implies, a virtual environment is a virtual environment. To put it more simply, the software that created the environment is floating in the air on the server in the personal computer. Is it an image like that? It has several boxes like containers, and it can be operated and executed for each of multiple containers with one hardware. That is a container-type virtual environment.
What is convenient is that by using a container type virtual environment (Docker this time), the environment created in the container can be started quickly and multiple applications can be executed. thing. The biggest advantage is that since we are creating a virtual environment, we can move the contents from PCs with different OS such as Windows and Mac under the same conditions. Isn't it a nice point that there are no problems with the execution environment due to differences in OS?
Here are some of the benefits.
-Since the execution environment is built, the program starts quickly. ・ Eliminate the difference between the development environment and the production environment ・ The same environment can be set up by sharing files. ・ Since you do not build the contents of your own PC, you do not have to install software.
and so on.
The Docker image is generally called the "foundation" required to create a container. A matryoshka-like image of a container that contains all the settings and libraries needed to run an application. If you pass this to another server, you can reproduce it as it is.
When you create a Dockre image, it becomes a container. When you run this container, you can recall the functions set in the Docker image inside. The Docker image is just an image, and when it comes to actually doing it, it becomes a container. (suitable)
DockerHub I think it's easy to understand if you can imagine GitHub. First of all, register as a Docker Hub user on some site. I didn't really understand at first because I entered from a place like this, but I remember registering for the time being. (Easy to be deceived) Dockrer images can be saved and handed over freely, so a service that saves them and distributes them to everyone. Images created by various users can be downloaded and saved, so the container can be started just by executing it, which is the same as a library. You can also clone GitHub and save it in your repository, right? something like that.
It seems that a service or location with such a storage function is called a registry. Let's remember.
The role for actually virtualizing the container. I think it's like a car, even if you only have a box, you can't move without power. I think it's okay to recognize that the Docker engine can use functions such as container creation, start, stop, and deletion.
looks strong. What is called a resident program. Operations and instructions such as creating a container and creating a Docker image are received and processed by the Docker daemon. Someone in virtualized software, like the last person in a phone game. He won't do anything unless this person is well prepared.
If it is stopped, it needs to be started.
Client software. A person who gives instructions using Docker commands. That's right.
For the time being, I only explained the word with the word Docker, It's a shallow knowledge that I just learned, so I think there are some mistakes. In that case, I would like you to say it carefully.
At a later date, I would like to summarize the details such as the explanation of Docker commands and the differences between Docker files and hosted virtualization. Thank you very much.
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