Docker Compose:

Docker Compose is used for creating a multicontainer architecture.

Docker Compose files are created using yaml or yml files and they are more re-usable.

Installing Docker Compose:

1. Open this site: https://docs.docker.com/compose/install/

2. click on linux tab and copy & paste the commands from 1 and 2.

3. After installation check whether in your linux/windows terminal is installed properly or not: docker-compose --version -> this command will display respective version what you have installed on your system it will display.

Steps to Write and perform actions over docker compose:

To Start the containers docker-compose up

To start the containers in detached mode docker-compose up -d

To stop the containers docker-compose stop

To stop and delete the containers docker-compose down

To see the list of processes in the containers docker-compose ps

To start the stopped container docker-compose start

To pause the excuting docker-compose pause

To unpause docker-compose unpause

1. To run the files which I uploaded here the format is :

   Syntax: docker-compose -f filename up -d

   • filename: you can give in which file you saved the docker-compose activity that file name should give over therr.

   • in my case i given like this compose1.yml

     eg: docker-compose -f compose1.yml up -d

2. To start the environment in detached mode:

   docker-compose -f compose1.yml up -d

3. To stop the environment:

   docker-compose -f compose1.yml stop -d

4. To delete the enviroment:

   docker-compose -f compose1.yml down -d

Usecase-1:

create a docker compose file for setting up a wordpress container and link with a mysql container

---

services: mydb: image: mysql:5 environment: MYSQL_ROOT_PASSWORD: chaithu

mywordpress: image: wordpress ports:

• 9999:80 links:
• mydb:mysql ...

Usecase-2: Create a docker compose file for setting up the CI-CD environment where a jenkins container is linked with 2 tomcat containers vim docker-compose.yml or nano docker-compose.yml

version: '3'

services: jenkinsserver: image: jenkins ports:

• 5050:8080

qaserver: image: tomcat ports:

• 6060:8080 links:
• jenkinsserver:jenkins

prodserver: image: tomcat ports:

• 7070:8080 links:
• jenkinsserver:jenkins ...

usecase-3: Create a Docker compose file to setup the LAMP Environment: vim docker-compose.yml

version: '3'

services: mydb: image: mysql:5 environment: MYSQL_ROOT_PASSWORD: chaithaya

apache: image: httpd ports:

• 9090:80 links:
• mydb:mysql

php: image: php:7.2-apache links:

• mydb:mysql
• apache:httpd

...

usecase-4: create a docker compose file to setup the selenium testing environment where a selenium hub container should be linked with chrome and firefox node containers.

---

version: '3'

services: hub: image: selenium/hub ports:

• 4444:4444

chrome: image: selenium/node-chrome-debug ports:

• 5901:5900 links:
• hub:selenium

firefox: image: selenium/node-firefox-debug ports:

• 5902:5900 links:
• hub:selenium

...