Docker
Docker containers wrap a piece of software in a complete filesystem that contains everything needed to run: code, runtime, system tools, system libraries – anything that can be installed on a server. This guarantees that the software will always run the same, regardless of its environment.
You will create containers by line commands.
Getting Started
Official documentation : https://www.docker.com/products/docker#/mac
Docker By Examples
Official documentation : https://docs.docker.com/engine/tutorials/dockerizing/
What is a container ?
A container is the space where we isolate the execution of a process.
Commands
# connect
$ docker exec -i -t [container name] bash# take id
$ docker ps# remove
$docker rm [id]
# remove more than one container
$docker rm $(docker ps -qa)
# remove images
$docker rmi [image name]
# initialize a container
$docker start [container name]
# stop a container
docker stop [container name]
How to connecting the containers ?
Example :
# new ubuntu container
$ docker run ubuntu bash# take the container id
$docker ps -a
# run bash process inside of contaner
$ docker exec -it d98d5602dc26 bashHow to run a process within the container and make the process output is displayed in the terminal?
$ docker exec -it [id container] [process name]Example:
$ docker exec -it d98d5602dc26 ps auxHow to kill a container ?
$ docker kill [id container]
Obs.:
To check : $ docker ps -a
Status of the finished container will find the number: 137 ( stopped by kill )
How to create a temp containers ?
$ docker run -it –rm ubuntu bash
How to install apache in a container ?
$ apt-get update && apt-get install -y apache2
How to define local ports ?
$ docker run -it -p [local]:[container] ubuntu/apache bashHow to automating the creation of images?
You need create a Dockerfile file. This file is used to define the commands to be executed.
# Example :
FROM mysql //imagem base
RUN apt-get update && apt-get install -y apache2 //executa a instrução de instalação do Apache
EXPOSE 80
CMD ["/usr/sbin/apache2clt", "-D", "FOREGROUND"]How to add a directory in a container ?
FROM ubuntu //imagem base
RUN apt-get update && apt-get install -y apache2 //install apache
ADD app /var/www/html
EXPOSE 80
CMD ["/usr/sbin/apache2clt", "-D", "FOREGROUND"]Hot to copy files to inside of a container ?
FROM ubuntu //imagem base
RUN apt-get update && apt-get install -y apache2 //install apache
COPY app /var/www/html
EXPOSE 80
CMD ["/usr/sbin/apache2ctl", "-D", "FOREGROUND"]How to create a bundle to save the keys ?
You need create a file-based key / value that serves as a flock to we store key values .
# Example :
Name : docker-compose.yml
db:
image: mysql
environment:
- MYSQL_ROOT_PASSWORD=test123
site:
image: wordpress
environment:
- WORDPRESS_DB_PASSWORD=test123
links:
- db:mysql
ports:
- 80:80How to keep saved data created in the container?
You must create a new file “docker-compose.yml” like as :
db:
image: mysql
volumes:
- ~/site/database/:/var/lib/mysql/In this scenario: The database data is saved in the folder / var / lib / mysql within the container.
What is the difference and how it works ?
www.Dev4Devs.com 