Docker from basics to advanced. Seamless infrastructure, CI, CD, deployment automation

1. LET’S DOCKERIZE

2. DOCKER IN ACTION
AGENDA
▸ Overview
▸ Concepts
▸ Architecture
▸ Installation
▸ Daily Operations
▸ References

3. DOCKER IN ACTION - OVERVIEW
WHAT IS DOCKER?
‣ Docker provides the ability to package and run an application in a
loosely isolated environment called a container.
‣ The isolation and security allow you to run many containers
simultaneously on a given host.
‣ Containers are lightweight because they don’t need the extra load of a
hypervisor, but run directly within the host machine’s kernel.
‣ This means you can run more containers on a given hardware
combination than if you were using virtual machines.
‣ You can even run Docker containers within host machines that are
actually virtual machines!

4. DOCKER IN ACTION - OVERVIEW
WHY DOCKER?
‣ Fast, consistent delivery of your applications
‣ Eliminates hacky deployments, mis-configuration, horrible cycles between the two
milestones “code passed testing” and “trying to deploy on production”.
‣ Responsive deployment and scaling
‣ Docker containers can run on a developer’s local laptop, on physical or virtual
machines in a data center, on cloud providers, or in a mixture of environments.
‣ Running more workloads on the same hardware
‣ Docker is lightweight and fast. It provides a viable, cost-effective alternative to
hypervisor-based virtual machines, so you can use more of your compute capacity to
achieve your business goals. Docker is perfect for high density environments and for
small and medium deployments where you need to do more with fewer resources.

5. DOCKER IN ACTION - CONCEPTS

6. DOCKER IN ACTION - CONCEPTS
IMAGES VS. CONTAINERS
‣ A container is launched by running an image. An image is
an executable package that includes everything needed to
run an application–the code, a runtime, libraries,
environment variables, and configuration files.
‣ A container is a runtime instance of an image–what the
image becomes in memory when executed (that is, an
image with state, or a user process). You can see a list of
your running containers with the command, docker ps,
just as you would in Linux.

7. DOCKER IN ACTION - CONCEPTS
CONTAINERS VS. VIRTUAL MACHINES
‣ A container runs natively on Linux and shares the kernel of
the host machine with other containers. It runs a discrete
process, taking no more memory than any other
executable, making it lightweight.
‣ By contrast, a virtual machine (VM) runs a full-blown
“guest” operating system with virtual access to host
resources through a hypervisor. In general, VMs provide an
environment with more resources than most applications
need.

8. DOCKER IN ACTION - CONCEPTS
CONTAINERS VS. VIRTUAL MACHINES

9. DOCKER IN ACTION - ARCHITECTURE
‣ Docker uses a client-server architecture.
‣ Docker client talks to the Docker daemon, which does the
heavy lifting of building, running, and distributing your
Docker containers.
‣ Docker client and daemon can run on the same system, or
you can connect a Docker client to a remote Docker daemon.
‣ Docker client and daemon communicate using a REST API,
over UNIX sockets or a network interface.
DOCKER ARCHITECTTURE

10. DOCKER IN ACTION - ARCHITECTURE
‣ The Docker daemon
The Docker daemon dockerd listens for Docker API requests and manages Docker objects such as
images, containers, networks, and volumes. A daemon can also communicate with other daemons to
manage Docker services.
‣ The Docker client
The Docker client (docker) is the primary way that many Docker users interact with Docker. When you
use commands such as docker run, the client sends these commands to dockerd, which carries them
out. The docker command uses the Docker API. The Docker client can communicate with more than one
daemon.
‣ Docker registries
A Docker registry stores Docker images. Docker Hub and Docker Cloud are public registries that anyone
can use, and Docker is configured to look for images on Docker Hub by default. You can even run your
own private registry. If you use Docker Datacenter (DDC), it includes Docker Trusted Registry (DTR).
DOCKER ARCHITECTTURE

11. DOCKER IN ACTION - ARCHITECTURE
DOCKER ARCHITECTTURE

12. DOCKER IN ACTION - ARCHITECTURE
When you use Docker, you are creating and using images, containers, networks, volumes,
plugins, and other objects. This section is a brief overview of some of those objects.
‣ IMAGES
An image is a read-only template with instructions for creating a Docker container. Often, an
image is based onanother image, with some additional customization. For example, you may
build an image which is based on the ubuntu image, but installs the Apache web server and
your application, as well as the configuration details needed to make your application run.
You might create your own images or you might only use those created by others and
published in a registry. To build your own image, you create a Dockerfile with a simple syntax
for defining the steps needed to create the image and run it. Each instruction in a Dockerfile
creates a layer in the image. When you change the Dockerfile and rebuild the image, only
those layers which have changed are rebuilt. This is part of what makes images so
lightweight, small, and fast, when compared to other virtualization technologies.
DOCKER OBJECTS

13. DOCKER IN ACTION - ARCHITECTURE
‣ CONTAINERS
A container is a runnable instance of an image. You can create, start, stop, move,
or delete a container using the Docker API or CLI. You can connect a container to
one or more networks, attach storage to it, or even create a new image based on
its current state.
By default, a container is relatively well isolated from other containers and its
host machine. You can control how isolated a container’s network, storage, or
other underlying subsystems are from other containers or from the host machine.
A container is defined by its image as well as any configuration options you
provide to it when you create or start it. When a container is removed, any
changes to its state that are not stored in persistent storage disappear.
DOCKER OBJECTS

14. DOCKER IN ACTION - INSTALLATION
INSTALLATION
▸ Windows 10 with Hyper-V supported HW:
▸ https://docs.docker.com/docker-for-windows/install/
▸ Windows 8.1, 8 and 7 or no Hyper-V supported HW:
▸ https://docs.docker.com/toolbox/toolbox_install_windows/
▸ Ubuntu:
▸ https://docs.docker.com/install/linux/docker-ce/ubuntu/#install-using-the-
repository
▸ macOS:
▸ https://docs.docker.com/docker-for-mac/install/

15. DOCKER IN ACTION - INSTALLATION
INSTALLATION PACKAGE
▸ Docker installation contains two main components:
▸ Docker Engine (core)
▸ Docker Compose

16. DOCKER IN ACTION - INSTALLATION
DOCKER ENGINE
Docker Engine is a client-server application with these major components:
‣ 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).

17. DOCKER IN ACTION - INSTALLATION
DOCKER ENGINE

18. DOCKER IN ACTION - INSTALLATION
DOCKER COMPOSE
‣ Compose is a tool for defining and running multi-container Docker applications.
‣ With Compose, you use a YAML file to configure your application’s services. Then,
with a single command, you create and start all the services from your
configuration.
‣ Compose works in all environments: production, staging, development, testing, as
well as CI workflows.
‣ Using Compose is basically a three-step process:
‣ Define your app’s environment with a Dockerfile so it can be reproduced anywhere.
‣ Define the services that make up your app in docker-compose.yml so they can be run together
in an isolated environment.
‣ Run docker-compose up and Compose starts and runs your entire app.

19. DOCKER IN ACTION - DAILY OPERATIONS
DAILY OPERATIONS
▸ Build new image for code updates:
▸ If this is the first time to build a docker image for this
code repo, you need to create an initial tag on source
code using this naming strategy master-0.0.0
▸ git checkout master
▸ git tag master-0.0.0
▸ If not, we can just run build.sh script to build a newer
version of the image.

20. DOCKER IN ACTION - DAILY OPERATIONS
DAILY OPERATIONS
▸ Build new docker image for code changes:
▸ If this is the first time to build a docker image for this code repo, you need to create an initial tag on
source code using this naming strategy master-0.0.0
▸ git checkout master
▸ git tag master-0.0.0
▸ Otherwise, you can just run build.sh script to build a newer version of the image.
▸ Script will do the following steps automatically for you:
▸ Check if there is any modifications done after the latest version of image.
▸ If any code modifications found; it will create a new tag on source code repo incremented by
1 (i.e. master-0.0.1).
▸ Push the new tag to source code repo.
▸ Build a new docker image as described in your Dockerfile
▸ Tag you new docker image with the already incremented tag version master-0.0.1
▸ Push your new docker image to your docker registry.
▸ Tag this image version as latest image.

21. DOCKER IN ACTION - DAILY OPERATIONS
DAILY OPERATIONS
▸ Deploy latest code to any docker environment (i.e.
laptop, testing, staging, production)
▸ Run docker-compose pull from the directory having
docker-compose.yml file to download newer image
version.
▸ Run docker-compose up -d to recreate only those
containers using updated images while other remain
uninterrupted.

22. DOCKER IN ACTION - DAILY OPERATIONS
DAILY OPERATIONS
▸ View running service(s) logs
▸ Run docker-compose logs -tf —tail=all to display
and follow all logs for all of your configured services in
docker-compose.yml file.
▸ To display logs for specific container(s) use this
command docker-compose logs -tf <service_name>
to recreate only those containers using updated images
while other remain uninterrupted.

23. DOCKER IN ACTION - REFERENCES
READ MORE ON
▸ https://docs.docker.com/
▸ https://docs.docker.com/install/
▸ https://docs.docker.com/get-started/part2/
▸ https://docs.docker.com/config/daemon/
▸ https://docs.docker.com/registry/
▸ https://docs.docker.com/registry/recipes/mirror/
▸ https://docs.docker.com/docker-hub/
▸ https://docs.docker.com/docker-store/
▸ https://docs.docker.com/machine/overview/
▸ https://docs.docker.com/docker-cloud/