This document provides an introduction to Docker, including its components, installation, basic workflow, usage scenarios and examples. Docker is presented as an alternative to virtual machines that provides OS-level virtualization through containers. It consists of a daemon, REST API and CLI client. Examples shown how to run basic services like Postgres and Wordpress in isolated containers on the local host. The document recommends Docker Hub for images and links to official documentation for further learning.

1. Campaign
proposal
Docker.
First steps.
Hack‘n’Tell

2. Docker against VM’s
- Docker container isn’t a VM
- Docker provides an additional
layer of abstraction of
operating-system-level
virtualization.
- Avoiding the overhead of starting
and maintaining virtual machines
(VMs).
- Provides resource isolation and
allocation benefits, but functions
differently because containers
virtualize the operating system
instead of hardware.
Hack‘n’Tell

3. Docker components
Docker consists of:
- A server which is a type of
long-running program called a
daemon process (the dockerd
command).
- A REST API which specifies
interfaces that programs can use
to talk to the daemon and instruct
it what to do.
- A command line interface (CLI)
client (the docker command).
Hack‘n’Tell

4. Docker installation
Your best choice:
https://www.docker.com/community-edition#/download
If you are on Linux (not prod):
https://get.docker.com/
Windows 10 Pro - your best friend.
Mac OS also supported.
Docker CE, Docker EE, Clouds, etc.
Hack‘n’Tell

5. Docker basic workflow Hack‘n’Tell
- Docker host - bare-metal or
virtual machine where Docker is
installed
- Client - command line interface to
communicate Docker daemon
(may or may not be installed on
the same machine as Docker
daemon).
- Registry - docker image storage
(docker hub, or private storage).
- Image - immutable file, snapshot
of a container.

6. Docker usage scenarios Hack‘n’Tell
- Setup local service - DB, queue,
portal, etc.
- Test your code - check how your
code works on different versions
of language without installing it on
host machine.
- Delivery - prepare and ship image
with preinstalled something (local
system, clouds).

7. Docker usage example 1 Hack‘n’Tell
- Setup local postgres service
docker run --name local-postgres -e POSTGRES_PASSWORD=mysecretpassword -d postgres

8. Docker usage example 2 Hack‘n’Tell
- Setup local wordpres & DB
1) docker run -e MYSQL_ROOT_PASSWORD=XXX -e MYSQL_USER=wpuser -e MYSQL_PASSWORD=XXX -e
MYSQL_DATABASE=wordpress_db -v wpdatabase:/var/lib/mysql --name wordpressdb -d mysql
2) docker run -e WORDPRESS_DB_USER=wpuser -e WORDPRESS_DB_PASSWORD=XXX -e WORDPRESS_DB_NAME=wordpress_db
-p 8081:80 -v wordpress:/var/www/html --link wordpressdb:mysql --name wpcontainer -d wordpress

9. Docker usage example 2 Hack‘n’Tell
- Check your node js script in different versions
docker run -it --rm --name continer-script -p 8080:8080 -v
/path/to/your/code/folder/on/host:/usr/src/app -w /usr/src/app node:4 node
your-daemon-or-script.js

10. Docker container not persistent Hack‘n’Tell
- All container images consist of
layers.
- Layers are created via image build
process and they are immutable.
- Container is a new read-write not
persistent layer on top of the
image.
- After container stopped - all
changes inside it will be reset to
the base image state.
- Container state can be saved to
image via command commit
(better not to do this)

11. Docker usage
Command line Purpose Example
docker pull <image name> Pull image from registry to host docker pull node:latest
docker run <image name> Run container from image docker run ngnix
docker ps
Show all running containers (look here for
container id)
docker ps
docker stop <container id> Stop running container docker stop 4e2802901fd7
docker rm <container id> Remove container docker rm 4e2802901fd7
docker images
Show all images present on host (look here
for image id)
docker images
docker rmi <image id> Remove image from the host docker rmi 3f44455b8f57
docker logs <container id> Logs from container stdout docker logs 4e2802901fd7
docker exec -it <container id>
<command>
Execute command inside container and show
stdout
docker exec -it 4e2802901fd7 ls -l /tmp
Hack‘n’Tell

12. Docker useful links Hack‘n’Tell
- https://hub.docker.com/ - image
storage
- https://docs.docker.com/ -
documentation, tutorials, api,
etc.
- https://labs.play-with-docker.co
m/ - playground, tutorials
(docker hub registration
required)
- https://docs.docker.com/develo
p/ - good place to continue from
this point

13. THANK YOU
avasyliev@intersog.com