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This article introduces the knowledge of "how to create a new container in Docker under Linux". In the operation of actual cases, many people will encounter such a dilemma, so let the editor lead you to learn how to deal with these situations. I hope you can read it carefully and be able to achieve something!

Hello, everyone. Today we will learn how to use a docker image to interactively create a Docker container. When we start a Docker process from a mirror, Docker takes the image and its parent image and repeats the process until the underlying image is reached. The federated file system (UFS) then adds a read-write layer at its top level. The read-write layer is called a container, which contains some information about the parent image and other information, such as unique ID, network configuration and resource restrictions. The container is stateful, and its state can be switched from the running state to the exit state. A container in the running state contains the process tree running on the CPU, isolated from other processes running on the host, while the exit state refers to the state of the file system and retains its exit value. You can use it to start, stop, and restart a container.

Docker technology has brought great changes to the IT world, it enables cloud services to share applications and workflow automation, enables applications to be quickly combined with components, and eliminates the friction between development, quality assurance and product environment. In this article, we will set up a CentOS environment and then use an Apache web server to provide a website service.

This is a quick and easy tutorial on how to use interactive shell to create a container interactively.

1. Run an instance of Docker

Docker will first try to get and run the required image locally, and if it is not found on the local host, it will pull it from the Docker public registry. Here, we will pull the image and create a fedora instance in the Docker container and connect to the bash shell on its tty.

The code is as follows:

# docker run-I-t fedora bash

two。 Install Apache network server

Now, after our basic Fedora image instance is ready, we will begin to interactively install the Apache network server instead of creating a Dockerfile for it. To do this, we need to run the following command on the terminal or shell.

The code is as follows:

# yum update

The code is as follows:

# yum install httpd

Exit the tty of the container.

The code is as follows:

# exit

3. Save Mirror

Now, we are going to save the changes made in the Fedora instance. To do this, we first need to know the container ID of the instance. In order to get the ID, we need to run the following command (LCTT: execute the command outside the container).

The code is as follows:

# docker ps-a

Then, we will save these changes to a new image, please run the following command.

The code is as follows:

# docker commit c16378f943fe fedora-httpd

Here, the changes have been saved by using the container ID, and the image name is fedora-httpd. To confirm that the new image is running, we will run the following command.

The code is as follows:

# docker images

4. Add content to a new mirror

Our own new Fedora Apache image is running successfully, and now we want to add some web content from our website to the Apache web server so that the website can be used right out of the box. To do this, we need to create a new Dockerfile that handles everything from copying web content to enabling port 80. To do this, we need to create a Dockerfile file using our favorite text editor, as demonstrated below.

The code is as follows:

# nano Dockerfile

Now, we need to add the following command line to the file.

The code is as follows:

FROM fedora-httpd

ADD mysite.tar / tmp/

RUN mv / tmp/mysite/* / var/www/html

EXPOSE 80

ENTRYPOINT ["/ usr/sbin/httpd"]

CMD ["- D", "FOREGROUND"]

Here, in the above Dockerfile, the web page content placed in the mysite.tar will be automatically extracted into the / tmp/ folder. The entire site will then be moved to the root of the Apache page / the var/www/html/, command expose 80 will open port 80 so that the site can be accessed properly. Second, the entry point is placed in / usr/sbin/https to ensure that the Apache server can execute.

5. Build and run a container

Now we are going to create our container with the Dockerfile we just created so that we can add our website to it. To do this, we need to run the following command.

The code is as follows:

# docker build-rm-t mysite

After setting up our new container, we need to run the container with the following command.

The code is as follows:

# docker run-d-P mysite

This is the end of the content of "how to create a new container in Docker under Linux". Thank you for reading. If you want to know more about the industry, you can follow the website, the editor will output more high-quality practical articles for you!

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