Docker Compose

Docker Compose is used to run multiple containers as a single service. For example, suppose you had an application which required NGNIX and MySQL, you could create one file which would start both the containers as a service without the need to start each one separately

Docker compose reads configuration data from a YAML file .

The key difference between docker run versus docker-compose is that docker run is entirely command line based, while docker-compose reads configuration data from a YAML file.

The second major difference is that docker run can only start one container at a time, while docker-compose will configure and run multiple.

Docker Compose Installation

First step is to check if Docker is installed or Not . We can check by using the below command. If Docker is not installed, than you need to install it

InstallCompose
Step 1 − Download the necessary files from github using the following command 
sudo curl -L "https://github.com/docker/compose/releases/download/1.10.0-rc2/dockercompose-$(uname -s) -$(uname -m)" -o /home/demo/docker-compose

Then, Run the below Command.

sudo curl -L "https://github.com/docker/compose/releases/download/v2.1.1/docker-compose-$(uname -s)-$(uname -m)" -o /usr/local/bin/docker-compose

Now, we need to give permissions, for that run the below command

Next, we need to provide execute privileges to the downloaded Docker Compose file, using the following command

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

We can then use the following command to see the compose version.

docker-compose version 

YAML: Yet   Another/Ain't   Mark Up Language

It is basically a key value pair.

vi example1-docker-compose.yaml

version: '3'

services:

  web:

   image: nginx

   container_name: demo

Now let’s run our Docker Compose file using the following command 

docker-compose -f example1-docker-compose.yaml up -d