README.md

Web stack debugging #0

Docker:

What is Docker and why is it popular?

• Docker is a platform and set of tools designed to make it easier to create, deploy, and run applications in isolated environments called containers. Containers allow developers to package an application and its dependencies into a single unit that can run consistently across different computing environments.
  

  Let’s first pull a Docker image and run a container:

   	vagrant@ubuntu-xenial:~$ docker ps
   	CONTAINER ID        IMAGE               COMMAND             CREATED             STATUS              PORTS               NAMES
   	vagrant@ubuntu-xenial:~$ docker run -d -ti ubuntu:16.04
   	Unable to find image 'ubuntu:16.04' locally
   	16.04: Pulling from library/ubuntu
   	34667c7e4631: Pull complete
   	d18d76a881a4: Pull complete
   	119c7358fbfc: Pull complete
   	2aaf13f3eff0: Pull complete
   	Digest: sha256:58d0da8bc2f434983c6ca4713b08be00ff5586eb5cdff47bcde4b2e88fd40f88
   	Status: Downloaded newer image for ubuntu:16.04
   	e1fc0d4bbb5d3513b8f7666c91932812da7640346f6e05b7cfc3130ddbbb8278
   	vagrant@ubuntu-xenial:~$ docker ps
   	CONTAINER ID        IMAGE               COMMAND             CREATED              STATUS              PORTS               NAMES
   	e1fc0d4bbb5d        ubuntu:16.04        "/bin/bash"         About a minute ago   Up About a minute                       keen_blackwell
   	vagrant@ubuntu-xenial:~$
  

  Note that docker command will pull the Ubuntu docker container image from the Internet and run it. I let you look at the meaning of the flags using the comm and docker run --help, the main idea is that it keeps the container up and running.

  To execute a command on the Docker container, use docker exec:

   vagrant@ubuntu-xenial:~$ docker exec -i e1fc0d4bbb5d hostname
   e1fc0d4bbb5d
   vagrant@ubuntu-xenial:~$ hostname
   ubuntu-xenial
   vagrant@ubuntu-xenial:~$
  

  If you want to connect to your Docker container and use Bash, you need to use docker exec -ti:

   vagrant@ubuntu-xenial:~$ docker exec -ti e1fc0d4bbb5d /bin/bash
   root@e1fc0d4bbb5d:/# echo "I am in $(hostname) Docker container"
   I am in e1fc0d4bbb5d Docker container
   root@e1fc0d4bbb5d:/# exit
   exit
   vagrant@ubuntu-xenial:~$
  

  If you want to stop a container, use docker stop:

   vagrant@ubuntu-xenial:~$ docker ps
   CONTAINER ID        IMAGE               COMMAND             CREATED             STATUS              PORTS               NAMES
   e1fc0d4bbb5d        ubuntu:16.04        "/bin/bash"         5 minutes ago       Up 5 minutes                            keen_blackwell
   vagrant@ubuntu-xenial:~$ docker stop e1fc0d4bbb5d
   e1fc0d4bbb5d
   vagrant@ubuntu-xenial:~$ docker ps
   CONTAINER ID        IMAGE               COMMAND             CREATED             STATUS              PORTS               NAMES
   vagrant@ubuntu-xenial:~$
  

How to installing Docker

• For this project you will be given a container which you can use to solve the task. If you would like to have Docker so that you can experiment with it and/or solve this problem locally, you can install it on your machine, your Ubuntu 14.04 VM, or your Ubuntu 16.04 VM if you upgraded.
  • Mac OS
  • Windows
  • Ubuntu 14.04(Note that Docker for Ubuntu 14 is deprecated and you will have to make some adjustments to the instructions when installing)
  • Ubuntu 16.04
  • For Zorin use this command:

   	sudo apt update && sudo apt install -y docker-compose