How docker constructs its own container

Docker is a very popular containerization platform. It has many advantages and can simplify the development, testing and deployment processes. To use Docker, you need to construct a Docker container. Let's talk about how to construct a Docker container yourself.

1. Install Docker

First you need to install Docker on your own machine. Docker supports multiple operating systems, such as Windows, Mac and Linux. After installing Docker, we can use Docker to construct containers.

2. Constructing a Docker container

The basic process of constructing a Docker container is as follows:

1. Prepare the Dockerfile file

The Dockerfile file is important for constructing the Docker container file, which contains the commands and configuration information we need to run in the container. You can use the command line or a text editor to create a Dockerfile file. It should be noted that the format of the Dockerfile file is fixed. If the format is incorrect, the Docker container cannot be constructed.

2. Construct a Docker image based on Dockerfile

Docker image is the basis of Docker container, and Docker image can be constructed through Dockerfile file. The command to construct an image is "docker build". This command needs to be executed in the directory where the Dockerfile is located. After executing this command, Docker will gradually construct the image according to the instructions in the Dockerfile.

3. Run the Docker container

After constructing the Docker image, we can construct the Docker container based on the image. The command to run a container is "docker run", which requires specifying parameters such as the image name and container name to be run. After executing this command, Docker will create and run a new Docker container.

The above is the basic process of constructing a Docker container. Let's introduce the specific details of each step separately.

3. Prepare the Dockerfile file

The Dockerfile file is used to specify the commands and configuration information required to construct a Docker image. It is an essential file for constructing a Docker container. The following is a simple Dockerfile example:

# 指定使用的基础镜像
FROM ubuntu:16.04

# 指定作者信息
MAINTAINER Your Name <your@email.com>

# 安装需要的软件包
RUN apt-get update && \
    apt-get install -y curl

# 复制文件到容器中
COPY ./index.html /var/www/html/

# 指定容器的工作目录
WORKDIR /var/www/html

# 暴露容器端口
EXPOSE 80

# 定义容器启动命令
CMD ["apache2ctl", "-DFOREGROUND"]

The above Dockerfile uses the "FROM" instruction to specify the base image as Ubuntu 16.04, and uses the "MAINTAINER" instruction to specify the author information. Then use the "RUN" command to install the "curl" software package, use the "COPY" command to copy the local "index.html" file to the container, use the "WORKDIR" command to specify the working directory of the container, and use "EXPOSE" The directive exposes the container's port.

Finally, use the "CMD" instruction to define the startup command of the container. The above instruction means to start the Apache server and make it run in the foreground. It should be noted that each instruction in the Dockerfile is executed sequentially. If the order of instructions is incorrect, the correct Docker container may not be constructed.

4. Construct a Docker image

After preparing the Dockerfile file, you can use the file to construct a Docker image. The command to construct the image is "docker build", which needs to be executed in the directory where the Dockerfile is located. The following is an example of a command to construct a Docker image:

docker build -t my-docker-image .

The above command uses the "-t" option to specify the name of the constructed image as "my-docker-image", and uses "." to indicate that the Dockerfile file is in the current in the directory. When this command is executed, Docker will construct the image according to the instructions in the Dockerfile file. After the construction is successful, the container can be run based on the image.

5. Run the Docker container

After constructing the Docker image, you can construct the Docker container based on the image. The command to run a container is "docker run", which requires specifying parameters such as the image name and container name to be run. The following is an example of a command to run a Docker container:

docker run -d -p 80:80 --name my-docker-container my-docker-image

The above command uses the "-d" option to specify that the container runs in the background, and the "-p" option specifies the port mapping of the container. The port is mapped to port 80 of the host. Use the "--name" option to specify the name of the container as "my-docker-container", and use "my-docker-image" to specify the name of the running image as "my-docker-image".

After executing this command, Docker will create and run a new Docker container. After successful operation, you can access the application in the container by accessing port 80 of the host.

Summary:

In the process of constructing a Docker container, you need to prepare the Dockerfile file, construct the image, and run the container in three steps. The Dockerfile file is used to specify the commands and configuration information required to construct a Docker image. Use the "docker build" command to construct a Docker image based on the Dockerfile file. Finally, use the "docker run" command to construct a Docker container based on the image.

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