Docker for Developers

Building web apps that run the same in multiple environments can be a time-consuming process. This work session we will learn how to use Docker and how you can efficiently build apps that run consistently across any machine. First, you'll learn about Docker, docker hub, Images, Container and commands. Next, you'll learn how to work with images, as well as Docker containers After that, you'll discover how to get a fully-functional development environment up and running. By the end of this session, you'll be able create lightweight apps that run the same no matter the environment.

##Installation on Linux

Prerequisites

• Install curl

sudo apt-get install curl

Install Docker

• Quick and easy docker Install by script:

curl -sSL https://get.docker.com/ | sh

• Add your user to docker group.

sudo usermod -aG docker $USER

• Start the docker daemon.

sudo service docker start

• Log out or restart your pc to ensures your user is running with the correct permissions.

• Verify your work by running docker without sudo.

docker run hello-world

#####Install Docker Composer

• docker compose install permission.

sudo chown -R $(whoami) /usr/local/bin

• Install docker compose

curl -L https://github.com/docker/compose/releases/download/1.8.0/docker-compose-`uname -s`-`uname -m` > /usr/local/bin/docker-compose

• docker compose executable permissions.

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

• Test the installation.

docker-compose --version

#####Optional

• Install Oh My Zsh with the Docker, git plugin for autocompletion of docker and git commands.

Docker commands

Pull, Run, Start, Stop and Restart

• docker pull pulls an image from docker registry to local machine.

  Usage:docker pull [OPTIONS] ImageName:TAG

  Example:docker pull nginx:1.11.9-alpine

• docker run creates and starts a container in one operation.

  Usage:docker run [OPTIONS] ImageName:TAG [COMMAND]

  Example:docker run -it --name nginx -p 80:80 -v /some/content:/usr/share/nginx/html:ro nginx:1.11.9-alpine

• docker start starts a container so it is running.

  Usage:docker start [OPTIONS] ContainerName or ContainerID [CONTAINER...]

• docker stopstops a running container.

  Usage:docker stop [OPTIONS] ContainerName or ContainerID [CONTAINER...]

• docker restart starts a container so it is running.

  Usage:docker restart [OPTIONS] ContainerName or ContainerID [CONTAINER...]

Build, Execute, Show, Rename, Remove

• docker buildcreates image from Dockerfile.

  Usage:docker build [OPTIONS] PATH | URL | -

  Example:Docker build -t YourImageName:tag . or Dockerfile location

• docker exec Run a command in a running container.

  Usage:docker exec [OPTIONS] CONTAINER COMMAND [ARG...]

  Example:Docker exec -it nginx bash or sh

• docker imagesshows all images.

• docker ps shows running containers.

• docker ps -a shows running and stopped containers.

• docker rename allows the container to be renamed.

  Usage:docker rename OldContainerName NewContainerName

• docker rm Remove one or more containers.

  Usage:docker rm [OPTIONS] ContainerName or ID [CONTAINER...]

  Example:Docker rm -f nginx Force the removal of a running container

• docker rmi Remove one or more images.

  Usage:docker rmi [OPTIONS] ImageName or ID [IMAGE...]

  Example:Docker rmi -f nginx Force removal of the image.

Debugging

• docker logs gets logs from container.

Usage:docker logs [OPTIONS] ContainerID or ContainerName

• docker inspectlooks at all the info on a container (including IP address)

  Usage:docker inspect [OPTIONS] ContainerID or ContainerName

• docker port shows public facing port of container.

Usage:docker port [OPTIONS] ContainerID or ContainerName

• docker top shows running processes in container.

Usage:docker top [OPTIONS] ContainerID or ContainerName

• docker statsshows containers' resource usage statistics.

Usage:docker stats [OPTIONS] ContainerID or ContainerName

• docker diff shows changed files in the container's FS.

Usage:docker diff [OPTIONS] ContainerID or ContainerName

Dockerfile

• FROM Sets the Base Image for subsequent instructions.

Usage: FROM <image>:<tag>

• MAINTAINER Set the Author field of the generated images.

Usage: MAINTAINER <name>

• RUN execute any commands in a new layer on top of the current image and commit the results.

Usage: RUN <command>

• CMD provide defaults for an executing container.

Usage: CMD ["executable","param1","param2"]

• EXPOSE informs Docker that the container listens on the specified network ports at runtime. NOTE: does not actually make ports accessible.

Usage: EXPOSE <port> [<port>...]

• ENV sets environment variable.

Usage: ENV <key> <value> or ENV <key>=<value>

• ADD copies new files, directories or remote file to container. Invalidates caches.

Usage: ADD <src>... <dest>

• COPY copies new files or directories to container.

Usage: COPY <src>... <dest>

• ENTRYPOINT configures a container that will run as an executable.

Usage: ENTRYPOINT ["executable", "param1", "param2"]

• VOLUME creates a mount point for externally mounted volumes or other containers.

Usage: VOLUME ["/data"]

• USER sets the user name for following RUN / CMD / ENTRYPOINT commands.

Usage: USER <userName>

• WORKDIR sets the working directory.

Usage: WORKDIR /path/to/workdir

• ARG defines a build-time variable.

Usage: ARG <name>[=<default value>]