Introduction to Docker Compose

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Docker Compose is a tool for creating and launching Docker applications by using a single command. We can use it to configure the application's services.

It is a powerful tool for development, testing and upgrading environments.

It provides the following commands to manage the entire lifecycle of an application:

Start, stop and rebuild services
View the status of running services
Stream the log output of the running service
Run a one-time command on the service

To implement docker compose, you need to include the following steps:

Put application environment variables in a Docker file for public access.
Provide and configure service names in the docker-compose.ymlfile so that they can run together in an isolated environment.
Run docker-composewill start and run the entire application.

Docker Compose installation

Here are the instructions to install Docker Compose in Ubuntu systems:

curl -L https://github.com/docker/compose/releases/download/1.21.2/docker-compose-`uname -s`-`uname -m` -o /usr/local/bin/docker-compose

Here is the download progress:

% Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
100   617    0   617    0     0    168      0 --:--:--  0:00:03 --:--:--   168
100 8649k  100 8649k    0     0  15651      0  0:09:25  0:09:25 --:--:-- 10383

Give permission to docker-composeadd execute:

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

View docker-composethe version of

docker-compose version

Docker Compose use

Create a docker-compose.ymlconfiguration file:

version: '3'
services:
  tomcat:
    restart: always
    image: tomcat
    container_name: tomcat
    ports:
      - 8000:8000

Parameter Description:

version: Specifies the script interpreter version
services: list of services to start
- webapp: service name, you can name it casually without repetition
  - restart: startup mode, here alwaysmeans always start, even if the server restarts, the service will be started immediately
  - image: The name of the image, downloaded from Docker Hub by default
  - container_name: The name of the container, you can name it arbitrarily without repetition
  - ports: Port mapping column list, the left is the host port, the right is the container port

Running in the foreground:

lusifer@UbuntuBase:/usr/local/docker/python$ docker-compose up
Creating network "python_default" with the default driver
Creating webapp ... 
Creating webapp ... done
Attaching to webapp
webapp    |  * Running on http://0.0.0.0:5000/ (Press CTRL+C to quit)

Background process:

lusifer@UbuntuBase:/usr/local/docker/python$ docker-compose up -d
Creating webapp ... 
Creating webapp ... done
lusifer@UbuntuBase:/usr/local/docker/python$

running result:

Docker Compose Command

Running in the foreground

docker-compose up

Background process

docker-compose up -d

start up

docker-compose start

stop

docker-compose stop

stop and remove container

docker-compose down