Docker Compose practice and summary

Docker Compose can realize the orchestration of Docker container clusters. We can define our services and their required dependencies through the docker-compose.yml file, and easily run them in test, production and other environments.

document

Product manuals

Compose file version 3 reference

Docker from Getting Started to Practice [Chinese]

Install Compose

Compose relies on Docker Engine, so you need to ensure that Docker is installed in your environment. You can refer to the official tutorial, which is mainly divided into two steps:

# 1. Download Compose and execute only the file to the usr/local/bin/ directory. # If the download fails, refer to the next summary to provide the address for installation. sudo curl -L "https://github.com/docker/compose/releases/download/1.29.2/docker-compose-$(uname -s)-$(uname -m)" -o /usr/local/bin/docker-compose

# 2. Add execution permissions to the Compose executable file sudo chmod +x /usr/local/bin/docker-compose

# Enter the following command to view the help and test whether the installation is successful docker-compose -h

Compose is open source in Docker's official GitHub repository: docker/compose. All Compose will be published in the Releases of the repository. Step 1 is to use the curl command to download the executable file from Releases. uname -s and uname -m can read the system's kernel name and hardware architecture to match the required Compose version. The -L parameter of curl will make the HTTP request follow redirects (not followed by default), and -o (lowercase o) will save the server response as a file and download it directly to: usr/local/bin/. The file name is: docker-compose. Because this path is already in the environment variable, after completing step 2 and adding executable permissions, you can use it anywhere.

Downloading directly from GitHub is slow. You can download it from the following address:

# https://vuepress.mirror.docker-practice.com/compose/install/
sudo curl -L https://download.fastgit.org/docker/compose/releases/download/1.27.4/docker-compose-`uname -s`-`uname -m` -o /usr/local/bin/docker-compose

sudo chmod +x /usr/local/bin/docker-compose

getting Started

The template instructions of Compose are very similar to the parameters related to the run command of Docker. If you forget the docker command, you can refer to the previous blog: Docker practice and command summary

There are two important concepts in Compose:

• Service: A container for an application, which can actually include several container instances running the same image
• Project: A complete business unit consisting of a set of related application containers, defined in the docker-compose.yml file

The format of docker-compose.yml is as follows. Note: YAML files must have a space after the key value : Indentation indicates hierarchy. Note that volumes and networks used in indentation must be declared.

#Specify version: "3"
# Collection of services services:
  # One of the services, service name: webapp
  webapp:
    # Specify the image used by the service: examples/web
    # Port mapping ports:
      - "80:80"
    # Data volumes:
      - "/data"

Easy to use

Start Tomcat, MySQL, and redis in a Compose and create docker-compose.yml

version: "3.0"

services:
  tomcat:
    container_name: mytomcat # --name
    image: tomcat:8.0-jre8
    ports:
      - "8080:8080"
    volumes:
      - "tomcatwebapps:/usr/local/tomcat/webapps"
    networks:
      -some_network
    # The tomcat service depends on mysql and redis
    depends_on:
      -mysql
      - redis
  mysql:
    container_name: mysql
    image:mysql:5.7.32
    ports:
      - "3306:3306"
    volumes:
      - "mysqldata:/var/lib/mysql"
      - "mysqlconf:/etc/mysql"
    environment:
      -MYSQL_ROOT_PASSWORD=1234
    networks:
      some_network:
  redis:
    container_name: redis
    image: redis:5.0.10
    ports:
      - "6379:6379"
    volumes:
      - "redisdata:/data"
    command: "redis-server --appendonly yes"
    networks:
      some_network:

# The volumes and networks used must declare volumes:
  tomcatwebapps: 
  mysqldata:
  mysqlconf:
  redisdata: 

networks:
  # Declare a network named "some_network":

Run docker-compose up in the path where docker-compose.yml is located to start the Compose project. It will download the used images and run the log in the foreground. You can use Ctrl + C to terminate it.

If you need to run docker-compose up -d in the background, you can use docker ps to see that Compose has created related containers based on yaml. Use docker-compose down to stop Compose and remove the automatically created bridge.

Use docker network ls to view the network or docker volume ls to view the data volume. The name format of the network or data volume defined by Compose is: the name of the folder where docker-compose.yml is located plus an underscore plus the name defined in YAML. If you create a YAML file in the "dockerfile" folder and start it, the network name is: dockerfile_some_network

The tomcat service uses depends_on , indicating that it depends on the redis and mysql services. Compose will start its dependencies first and then start it.

Command Sorting

The commands of Docker Compose are similar to those of Docker. You can use the --help parameter to query the usage of the corresponding command.

docker-compose --help

The default startup template file is named docker-compose.yml. You can use -f to specify a custom template file. You can use the config command to check whether the template file syntax is correct.

docker-compse also includes many subcommands:
Start and stop related: up, down, restart, stop, pause, unpause

Resources related: ps, top, kill, run

Enter the container: exec

View logs: logs

Many subcommands can be followed by a specific service name for targeted operations. The following are not listed one by one.
You can use docker-compose help followed by the subcommand name to query its usage

# Start all containers defined in yaml in the background docker-compose up -d
#Starting only the mysql service will start its dependent services
docker-compose up mysql specifies the server name to start.
# Stop the container and remove the automatically created bridge docker-compose down 
# Restart all services and then specify a specific service
docker-compose restart

# Pause and resume docker-compose pause
docker-compose unpause

# Enter the redis service and exit docker-compose exec redis bash

# List the information of the container defined in the current yaml docker-compose ps

# Delete the container defined in the current yaml. You need to stop it first, and then specify a specific service
docker-compose rm

# View the processes running in each service container docker-compose top

# View logs by default. View all YAML files. You can follow the specific service.
# -f can keep tracking, new logs will be displayed on the screen immediately docker-compose logs

References

Curl Usage Guide [Programming Bad People] Docker Container Technology & Docker-Compose Practice

This is the end of this article about Docker Compose practice and summary. For more relevant Docker Compose practice content, please search 123WORDPRESS.COM’s previous articles or continue to browse the following related articles. I hope everyone will support 123WORDPRESS.COM in the future!