What should I do if docker does not exit when it starts?

Docker is an open source platform based on container technology, which can easily package applications into an independent portable container for deployment. However, when using Docker, sometimes the container may exit immediately after starting it. At this time, we need to find the cause and solve the problem.

1. Check the startup status of the Docker container

You can check the startup status of the Docker container by executing the following command:

docker container ls -a

This command Basic information of all containers will be displayed, including container ID, name, status, port, etc. We can determine whether the container is running by checking the status of the container.

If the status of the container is Exited, it means that the container has exited. We need to find out the problem that caused the container to exit.

2. Check the container log information

There are many reasons for the container to exit after starting, including configuration errors, service not starting, port conflicts, etc. We can find out the specific reason why the container failed to start by looking at the container's log information.

Execute the following command to view the log information of the container:

docker logs [container-name]

You can use this command to view the standard output (stdout) and standard error of the container Output (stderr) to quickly locate the problem.

3. Start the Docker container and keep it running

When using Docker, we can use parameters to prevent the container from exiting after starting. Commonly used parameters are as follows:

docker run -d [image-name] [command]

The -d parameter indicates starting the container in the background. Without this parameter, the container will run in the foreground. The command parameter indicates the command that needs to be executed after the container is started.

For example, when starting an Nginx container, you can use the following command:

docker run -d -p 80:80 nginx

This command starts an Nginx container, And map port 80 of the host to port 80 of the container so that we can access the Nginx service through the browser.

4. Use Docker Compose to manage containers

Docker Compose is a tool that can manage multiple containers and can easily complete tasks such as deploying, starting and stopping multi-container applications.

By writing the docker-compose.yml file, you can define a set of containers, including the container's running parameters, dependencies, network configuration, etc. We can then use the docker-compose command to start, stop and manage these containers.

For example, when starting a WordPress website, you can use the following docker-compose.yml file:

version: '3.3'

services:
db:

image: mysql:5.7
volumes:
  - db_data:/var/lib/mysql
restart: always
environment:
  MYSQL_ROOT_PASSWORD: somewordpress
  MYSQL_DATABASE: wordpress
  MYSQL_USER: wordpress
  MYSQL_PASSWORD: wordpress

wordpress:

depends_on:
  - db
image: wordpress:latest
ports:
  - "80:80"
restart: always
environment:
  WORDPRESS_DB_HOST: db:3306
  WORDPRESS_DB_USER: wordpress
  WORDPRESS_DB_PASSWORD: wordpress

volumes:

db_data:

This file defines a MySQL container and a WordPress container, where the WordPress container depends on the MySQL container. By using the docker-compose up command, you can start these two containers and create a WordPress website.

Summary

Docker can help us quickly deploy applications and achieve application independence and portability through container technology. However, when using Docker, we also need to pay attention to the startup status of the container, check the container log information in a timely manner, and take appropriate measures to solve the problem. In addition, by using Docker Compose, we can easily manage multiple containers, improving application deployment efficiency and reliability.

The above is the detailed content of What should I do if docker does not exit when it starts?. For more information, please follow other related articles on the PHP Chinese website!